melting history and magmatic evolution of basalts and ... · basalts and picrites from the...

Melting History and Magmatic Evolution ofBasalts and Picrites from the AccretedWrangelliaOceanic PlateauVancouver Island Canada

ANDREW R GREENE1 JAMES S SCOATES1 DOMINIQUE WEIS1GRAHAM T NIXON2 AND BRUNO KIEFFER1

1PACIFIC CENTRE FOR ISOTOPIC AND GEOCHEMICAL RESEARCH DEPARTMENT OF EARTH AND OCEAN SCIENCES

UNIVERSITY OF BRITISH COLUMBIA VANCOUVER BC V6T1Z4 CANADA2BRITISH COLUMBIA GEOLOGICAL SURVEY PO BOX 9320 STN PROV GOVT VICTORIA BC V8W9N3 CANADA

RECEIVED MARCH 18 2008 ACCEPTEDJANUARY 23 2009

The accretedWrangellia oceanic plateau in the Pacific Northwest of

North America provides important insights into the volcanic archi-

tecture of major oceanic plateaus as well as the nature of their

mantle source conditions of melting and subsequent magmatic evolu-

tion The 20 000 km2 Karmutsen Formation flood basalts

(Vancouver Island) were emplaced at c 225^230 Ma onto Middle

Triassic marine sediments and Late Devonian to Early Permian

island-arc volcanic and sedimentary sequences and are overlain by

LateTriassic platformal carbonatesThe basalts form an emergent

sequence consisting of a basal sediment^sill complex (600^900 m

thick) pillowed and massive submarine flows (425 km) pillow

breccia and hyaloclastite (515 km) and massive subaerial flows

(525 km) Although the Karmutsen Formation is predominantly

composed of tholeiitic basalt the submarine part of the stratigraphy

on northern Vancouver Island also contains picritic basalts These

high-MgO (9^20 wt ) lavas are depleted in light rare earth ele-

ments (LREE LaYbCNfrac14 05 02) whereas the tholeiitic lavas

(6^8 wt MgO) are LREE-enriched (LaYbCNfrac14 22 03)

Both lava groups have overlapping initial eHf(thorn103 21) and

eNd(thorn7713) indicating a common plume-type Pacific mantle

source with geochemical characteristics similar to the source of

basalts from the Ontong Java and Caribbean plateaus Major-ele-

ment modeling results indicate that the picrites formed by extensive

melting (23^27) of anomalously hot mantle (15008C) which isconsistent with a mantle plume initiation model for formation of the

Karmutsen flood basalts on Vancouver Island Trace element

constraints indicate that the picrites require melting of a depleted

spinel lherzolite source whereas the tholeiitic basalts involved melt-

ing of garnet and spinel lherzoliteThe tholeiitic basalts underwent

significant fractional crystallization (450) and the fractionated

residues may be represented by high-velocity rocks beneathVancouver

Island identified from seismic reflection studies

KEYWORDS Karmutsen Formation mantle plume large igneous prov-

ince picrite tholeiitic basalt

I NTRODUCTIONOceanic plateaus are transient large igneous provinces thattogether with continental flood basalts represent the pro-ducts of the largest magmatic events preserved on Earthfrom the Phanerozoic era There are some 10 oceanic pla-teaus that have formed in the last 145 Myr ranging in sizefrom 100 000 to 2106 km2 and collectively they cover anarea of about 10106 km2 (3) of the ocean basinsmostly in the Pacific and Indian oceans (eg Eldholm ampCoffin 2000) Oceanic plateaus form submarine or subaer-ial flood basalt sequences that can be 6 km thick withtotal crustal thicknesses (extrusive plus intrusive rocks) of8^33 km (eg Coffin amp Eldholm1994) Several key aspectsof most large igneous provinces are that they form as a

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JOURNALOFPETROLOGY VOLUME 00 NUMBER 0 PAGES1^39 2009 doi101093petrologyegp008

Journal of Petrology Advance Access published March 9 2009

result of unusually high melt production rates are predo-minantly basaltic in composition and their formation isnot directly attributable to seafloor spreading processes(eg Saunders 2005) The high melt production rates arebest explained by high mantle source temperatures in rap-idly upwelling mantle (ie mantle plumes) direct evidenceof high mantle temperatures is the eruption of primitivehigh-MgO lavas (Kerr amp Mahoney 2007) Studies of oce-anic plateaus can be used to constrain aspects of mantleplume-related magmatism including the composition ofthe mantle source involved the temperature and depth ofmelting the volume of magma and melt production ratesand the mechanisms of emplacement of voluminous lavasequences From a geochemical perspective the study ofoceanic plateaus is important because the chemistry of thelavas has generally been unaffected by continental crustalcontaminationAt present one of the great challenges in studying oce-

anic plateaus in the ocean basins is the difficulty in drillingto depths of more than a few hundred meters into thebasaltic basement rocks (eg Kerguelen Ontong Java)Accreted sections of oceanic plateaus (eg CaribbeanOntong Java) provide an opportunity to closely examinetheir volcanic stratigraphyWrangellia flood basalts in thePacific Northwest of North America are part of a majorlarge igneous province that erupted in a marine setting inthe Late Triassic (c 225^231 Ma) and accreted to westernNorth America in the Late Jurassic or Early Cretaceous(Richards et al 1991) Although their original areal distri-bution was probably considerably larger much of the orig-inal stratigraphic thickness (6 km on Vancouver Island35 km in Alaska) is intact Current exposures of theflood basalts are preserved in a narrow belt over 2300 kmin length resulting from transform fault motions afteraccretion which extends from southern British Columbiathrough the Yukon and into Alaska Richards et al (1991)proposed a plume initiation model for the Wrangelliaflood basalts based on the short duration and estimatedhigh eruption rate of the volcanism evidence of upliftprior to volcanism and lack of evidence of associated rift-ing (ie few dikes and abundant sills)TheWrangellia flood basalts are perhaps the most exten-

sive accreted remnants of an oceanic plateau in the worldwhere parts of the entire volcanic stratigraphy areexposed however they have been the focus of few inte-grated field geochemical and radiogenic isotopic studiesThe internal architecture of oceanic plateaus can provideconstraints on the sequence of melting events associatedwith mantle plumes that occur beneath the oceans in ananalogous way to the use of continental flood basalts toelucidate the sequential development of mantle plumesand rifting within continental lithosphere (eg Peate 1997Storey et al 1997) The internal stratigraphy of continentalflood basalts is far more complex than previously realized

(eg Jerram amp Widdowson 2005) and because of theirrelative inaccessibility the structure of flood basaltsequences in oceanic plateaus is not well known In thisstudy we examine the field relationships petrographymajor and trace elements and Sr^Nd^Hf^Pb isotopiccompositions of Wrangellia flood basalts from variousareas of Vancouver Island to assess the nature of themantle source conditions of melting and magmatic his-tory of the basalts in the context of the construction ofthis major oceanic plateau This study is part of a compre-hensive research project on the nature origin and evolu-tion of the Triassic Wrangellia flood basalt province inBritish Columbia Yukon and Alaska (Greene et al 20082009)

GEOLOGICAL SETT INGWrangellia on Vancouver IslandWrangellia flood basalts form the core of the Wrangelliaterrane orWrangellia one of the largest outboard terranesaccreted to western North America (Jones et al 1977)Middle to LateTriassic flood basalts extend in a discontin-uous belt from Vancouver and Queen Charlotte Islands(Karmutsen Formation) through SE Alaska and SWYukon and into the Wrangell Mountains Alaska Rangeand Talkeetna Mountains in east and central Alaska(Nikolai Formation Fig 1)Wrangellia covers 80 of Vancouver Island which is

460 km long by 130 km wide (Fig 1) Wrangellia is theuppermost sheet of a stack of SW-vergent thrust sheetsthat form the crust of Vancouver Island and has a cumula-tive thickness of410 km (Monger amp Journeay 1994) Pre-Karmutsen units of Wrangellia on Vancouver Islandinclude Devonian arc sequences of the Sicker Group andMississippian to Early Permian siliciclastic and carbonaterocks of the Buttle Lake Group (Muller 1980 Sutherland-Brown et al1986)These Paleozoic sequences have variableestimated thicknesses (2^5 km Muller 1980 Massey1995a) and are exposed only on central and southernVancouver Island (Fig 1) The Karmutsen Formation isoverlain by the shallow-water Quatsino limestone (30^750m) and shallow- to deeper-water Parson BayFormation (600m) which is intercalated with and over-lain by Bonanza arc volcanics (169^202 Ma Nixon et al2006b) Bonanza arc plutonic rocks (167^197 Ma) alsointrude the Karmutsen Formation and are some of theyoungest units of Wrangellia that formed prior to accretionwith North America (Nixon et al 2006b) Following accre-tionWrangellia units were intruded by the predominantlyCretaceous Coast Plutonic Complex (Wheeler amp McFeely1991)The Karmutsen Formation (19142 km2 calculation

based on digital geological compilations) is composed ofbasal sediment^sill complexes a lower unit of pillowed

JOURNAL OF PETROLOGY VOLUME 00 NUMBER 0 MONTH 2009

2

and massive submarine flows a middle unit of mostlypillow breccia and hyaloclastite and an upper unit of pre-dominantly massive subaerial flows (Carlisle amp Suzuki1974) The pillow basalts directly overlie Middle Triassicand late Paleozoic marine sedimentary sequences that areintruded by Karmutsen mafic sills The boundary betweenpillow breccia^hyaloclastite and massive lava flows repre-sents the transition from a submarine to a subaerial erup-tive environment The uppermost flows of the Karmutsenare intercalated with and overlain by shallow-water lime-stone and local occurrences of pillowed flows and hyalo-clastite deposits occur within the upper subaerial memberThe Karmutsen Formation and Wrangellia on Vancouver

Island have been the focus of detailed mapping and strati-graphic studies by Carlisle (Carlisle 1963 1972 Carlisle ampSuzuki 1974) and Muller (Muller et al 1974 Muller 1977)Recent descriptions of the Karmutsen Formation on north-ern Vancouver Island have been made during regionalmapping studies (150 000 scale) by Nixon and coworkers(Nixon et al 2006b 2008 Nixon amp Orr 2007)

Age of the Karmutsen FormationThe age and duration of Karmutsen volcanism are con-strained by fossils in the underlying and overlying sedi-mentary units and by three U^Pb isotopic age

Fig 1 Simplified map of Vancouver Island showing the distribution of the Karmutsen Formation and underlying Paleozoic formations (afterMassey et al 2005a 2005b) Areas in white are mostly younger units The main areas of field study are indicated with boxes or circles withcapital letters (see legend) Ocean is light blue The inset shows the extent of theWrangellia flood basalts (green) in British Columbia Yukonand Alaska

GREENE et al WRANGELLIA FLOOD BASALTS ON VANCOUVER ISLAND

3

determinations on intrusive rocks that are considered to berelated to the Karmutsen volcanics Daonella-bearing shale100^200m below the base of the pillow basalts on SchoenMountain and Halobia-rich shale interlayered with flows inthe upper part of the Karmutsen indicate eruption of mostof the flood basalts between the Middle Ladinian (c 232^235 Ma Middle Triassic) and latest Carnian or possiblyearliest Norian (c 216^227 Ma Late Triassic Carlisle ampSuzuki 1974) The only published U^Pb age is based on asingle concordant analysis of a multi-grain baddeleyitefraction from a gabbro on southernVancouver Island thatyielded a 206Pb238U age of 227326 Ma (Parrish ampMcNicoll 1992) Two unpublished 206Pb238U baddeleyiteages also from a gabbro on southern Vancouver Islandare 226805 Ma (five multi-grain fractions) and228425 Ma (two multi-grain fractions Sluggett 2003)

VOLCANIC STRAT IGRAPHY ANDPETROGRAPHYFieldwork undertaken onVancouver Island as part of thisstudy in 2004^2006 explored the volcanic stratigraphy ofthe Karmutsen flood basalts in three main areas theKarmutsen Range (between Alice and Nimpkish lakes)the area around Schoen Lake Provincial Park and atMount Arrowsmith (Greene et al 2005 2006) areasaround Holberg Inlet in northernmost Vancouver Islandand Buttle Lake in central Vancouver Island were alsoinvestigated (Fig 1) The character and thickness of theflood basalt sequences vary locally although the tripartitesuccession of the Karmutsen Formation appears to be pres-ent throughout Vancouver Island The stratigraphic thick-nesses for the pillow volcaniclastic and subaerial flowunits in the type area around Buttle Lake are estimated tobe 2600m 1100m and 2900m respectively (Surdam1967) estimated thicknesses on northernVancouver Islandare 43000m 400^1500m and 41500m respectively(Nixon et al 2008) in the vicinity of Mount Arrowsmithand nearby areas on southern Vancouver Island thick-nesses are 1100m 950m and 1200m respectively (Yorathet al 1999 Fig 1)Picritic pillow lavas west of the Karmutsen Range on

northernVancouver Island occur in a roughly triangular-shaped area (30 km across) bounded by KeoghMaynard and Sara lakes (Figs 2 and 3 Greene et al2006 Nixon et al 2008) Excellent exposures of picriticpillow lavas occur in roadcuts along the north shore ofKeogh Lake the type locality (Greene et al 2006) TheKeogh Lake picrites form pillowed and massive flow units(515m thick Fig 3) with pillows and tubes of varieddimensions (typically51m wide) Numerous thermal con-traction features in the pillows are filled with quartz^carbonate such as drain-back ledges and tortoise-shelljointing (Greene et al 2006) The picritic pillow basalts

are not readily distinguishable in the field from basaltexcept by their density non-magnetic character and com-paratively minor amounts of interpillow quartz^carbonateFieldwork and mapping indicates that the picrites occurnear the transition between the uppermost pillow lavasand the lowermost part of the volcaniclastic unit (Nixonet al 2008)In and around Schoen Lake Provincial Park where

the base of the Karmutsen Formation is exposed is asediment^sill complex consisting of Middle Triassic andPennsylvanian to Permian limestones and fine-grained sili-ciclastic sedimentary rocks intruded by mafic sills andoverlain by pillow basalt (Figs 2 and 4 Carlisle 1972) Thesediment^sill complex is 600^900m thick whichincludes 150^200m of pre-intrusive sedimentary rocks(Carlisle 1972) TheTriassic sedimentary rocks range fromthinly bedded siliceous and calcareous shales to bandedcherts and finely laminated Daonella-bearing shales(Carlisle 1972) Basal sills and pre-Karmutsen sedimentsare also exposed around Buttle Lake (Fig 1)Exposures with considerable vertical relief around

Mount Arrowsmith (see Electronic Appendix 1 availablefor downloading at httppetrologyoxfordjournalsorg)and Buttle Lake preserve thick successions of submarinepillow basalts and pillow breccias with rare intercalationsof sediment and subaerial flows Massive submarine flowsin the pillow unit are locally recognizable by their irregu-lar hackly columnar jointing The massive subaerial flowsform monotonous sequences marked mainly by amygdaloi-dal horizons brecciated flow tops are rarely observedA locality with well-preserved pahoehoe flow features iswell exposed north of Holberg Inlet (Fig 3 Nixon amp Orr2007 Nixon et al 2008) There is no evidence of significantdetrital material from a continental source in the sedi-ments associated with the flood basalts anywhere onVancouver Island The uppermost Karmutsen flows areinterbedded with thin (commonly 0^4m thick) lenses oflimestone and rarely siliciclastic sedimentary rocks(Nixon et al 2006b) Plagioclase-phyric lavas characterizethe upper part of the subaerial sequence and locallyinclude distinctive plagioclase-megacrystic (1^2 cm crys-tals) trachytoid-textured flows (Nixon et al 2006b)A total of 129 samples were collected from the

Karmutsen Formation on Vancouver Island from which63 samples were selected for geochemical analysis basedon the relative degree of alteration and geographical distri-bution of the samples Fifty-six of these samples weredivided into four main groups based on petrography(Table 1) and geochemistry tholeiitic basalt picrite high-MgO basalt and coarse-grained mafic rocks In additiontwo outlying samples and a mineralized sill are distin-guished in Table 1 The tholeiitic basalts are dominantlyglomeroporphyritic and less commonly aphanitic withan intersertal to intergranular groundmass (Table 1)


4

Fig 2 Geological map and stratigraphy of the Schoen Lake Provincial Park and Karmutsen Range areas (locations shown in Fig 1 northernVancouver Island) (a) Stratigraphic column depicts units exposed in the Schoen Lake area derived from Carlisle (1972) and fieldwork (b)Generalized geology for the Schoen Lake area with sample locations Map derived from Massey et al (2005a) The exposures in the SchoenLake area are the lower volcanic stratigraphy and base of the Karmutsen Formation (c) Stratigraphic column for geology in the Alice^Nimpkish Lake area derived from Nixon amp Orr (2007) (d) Geological map from mapping of Nixon et al (2006a 2008) Sample sites andlithologies are denoted in the legend The Keogh Lake picrites are exposed near Keogh Sara and Maynard lakes and areas to the east ofMaynard Lake (Nixon et al 2008)


5

Fig 3 Photographs of picritic and tholeiitic pillowed and massive basalt flows from the Karmutsen Range (Alice and Nimpkish Lake area)and Holberg Inlet (HI) areas northernVancouver Island (locations shown in Fig 1) (a) Massive submarine flow (marked with arrows) drapedover high-MgO pillow basalt of similar composition (b) Picritic pillow basalts in cross-section near Maynard Lake (Note vesicular uppermargin to pillows) (c) Close-up photograph of undulating contact of massive submarine flow draped over high-MgO pillow basalt (markedwith arrows) from photograph (a) (area of photograph indicated with a white box) (d) Photograph of margin of pahoehoe lobe (sledgehammerfor scale) (e) Cross-section of a large picritic pillow lobe with infilling of quartz^carbonate in cooling^contraction cracks (sledgehammer forscale) (f) High-MgO pillow breccia stratigraphically between submarine and subaerial flows (arrow points to lens cap 7 cm diameter forscale)


6

Plagioclase forms most of the phenocrysts and glomero-crysts and the groundmass is fine-grained comprising pla-gioclase microlites clinopyroxene granules small grains ofFe^Ti oxide devitrified glass and secondary minerals

there is no fresh glass preserved The picritic and high-MgO basaltic lavas are characterized by spherulitic plagi-oclase and clinopyroxene with abundant euhedral olivinephenocrysts (Fig 5 Table 1) Olivine is completely replaced

Fig 4 Photographs showing field relations from the Schoen Lake Provincial Park area northernVancouver Island (a) Sediment^sill complexat the base of the Karmutsen Formation on the north side of Mt Schoen 100m below the Daonella locality (see Fig 2 for location) (b)Interbedded mafic sills and deformed finely banded chert and shale with calcareous horizons from location between Mt Adam and MtSchoen

Fig 5 Photomicrographs of picritic pillow basalts Karmutsen Formation northernVancouver Island Scale bars represent 1mm (a) Picritewith abundant euhedral olivine pseudomorphs from Keogh Lake type locality (Fig 2) in cross-polarized light (XPL) (sample 4722A4 19^198wt MgO four analyses) Samples contain dense clusters (24^42 vol ) of olivine pseudomorphs (52mm) in a groundmass of curvedand branching sheaves of acicular plagioclase and intergrown with clinopyroxene and altered glass In many cases plagioclase nucleated on theedges of the olivine phenocrysts (b) Sheaves of intergrown plagioclase and clinopyroxene in aphyric picrite pillow lava from west of MaynardLake (Fig 2) in XPL (sample 4723A2108 wt MgO)


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Table 1 Summary of petrographic characteristics and phenocryst proportions of Karmutsen basalts on Vancouver Island

BC

Sample Area Flow Group Texture vol Ol Plag Cpx Ox Alteration Notes

4718A1 MA PIL THOL intersertal 20 5 3 few plag glcr52mm cpx51 mm

4718A2 MA PIL THOL intersertal glomero 15 1 plag glcr52mm very fresh

4718A5 MA FLO THOL intersertal glomero 10 2 mottled few plag glcr54 mm

4718A6 MA BRE THOL porphyritic 20 2 plag 5ndash6mm sericite alteration

4718A7 MA PIL THOL glomero 10 3 plag glcr53 mm

4719A2 MA PIL THOL porphyritic intersertal 5 3 plag glcr52 mm


4720A2 SL BRE THOL glomero 5 3 plag glcr52 mm

4720A3 SL FLO THOL glomero 3 3 plag glcr53 mm

4720A4 SL FLO THOL glomero 5 1 plag glcr55mm slightly cg very fresh

4720A5 SL PIL THOL seriate 20 3 plag glcr52mm plag needles and laths

4720A8 SL FLO THOL glomero 20 2 plag glcr52mm plag needles and laths


4721A1 SL PIL THOL glomero 15 3 plag glcr515mm plag needles aligned

4721A2 SL FLO THOL glomero 10 1 plag glcr53mm very fresh

4721A3 SL FLO THOL glomero 20 3 plag glcr52mm plag needles

4721A4 SL FLO THOL glomero ophimottled 20 5 1 plag glcr515mm cpx51mm (oik) very fresh

4721A5 SL FLO THOL glomero ophimottled 5 15 3 plag glcr515mm cpx51mm (oik)

4722A2 KR FLO THOL intergranular intersertal 1 1 few plag phenos52 mm

4723A10 KR FLO THOL intergranular 5 3 10 3 few plag glcr51mm ox 05ndash1 mm

4724A5 SL FLO THOL porphyritic 25 3 plag 7ndash8 mm

5614A10 KR FLO THOL intergranular intersertal 2 5 3 ox505 mm

5614A11 KR FLO THOL intergranular intersertal 5 7 3 ox 05ndash1 mm

5614A13 KR FLO THOL intergranular porphyritic 5 5 3 ox 05ndash1 mm

5615A1 KR PIL THOL aphyric intersertal 1 2 fg no phenos

5615A8 KR PIL THOL intergranular 3 1 fg abundant small ox very fresh

5615A10 KR PIL THOL intergranular 3 3 2 plag glcr54 mm


5618A1 QI FLO THOL intergranular 3 2 10 3 ox 05ndash2mm cg plag laths42 mm

4720A6 SL FLO CG subophitic 15 1 plag glcr53mm cpx53 mm

4720A7 SL FLO CG subophitic 25 1 plag chad515mm cpx oik52mm very fresh

4720A10 SL SIL CG subophitic intrafasciculate 5 3 plag chad52mm cpx oik53mm ox51mm cg

4724A3 SL FLO CG ophimottled subophitic 5 30 5 3 plag glcr 4ndash5mm cpx oik52mm ox51 mm

5614A14 KR SIL CG intergranular 10 5 3 plag51mm cpx52 mm

5614A15 KR SIL CG subophitic 25 3 1 plag51mm cpx oik53mm ox502 mm

5615A5 KR GAB CG intergranular plag-phyric 30 5 3 ox505mm plag laths54 mm

5615A6 KR GAB CG intergranular plag-phyric 15 10 3 plag53mm ox 05ndash15 mm

5616A3 KR GAB CG subophitic 25 5 1 plag laths51mm cpx oik52mm ox 05ndash1 mm

5617A1 SL SIL CG intergranular intergrowths 30 3 plag53mm cpx55mm cpxndashplag intergrowths

5617A5 SL SIL CG intergranular intersertal 1 1 plag51mm fg mottled

93G171 KR PIL PIC subophitic 23 ol523mm cpx515mm partially enc plag

4722A4 KR PIL PIC cumulus intergranular 35 10 3 ol515mm cpx52mm enc plag

4723A3 KR PIL PIC spherulitic 31 3 ol51mm swtl plag515 mm

4723A4 KR PIL PIC intergranular intersertal 0 3 swtl plag51mm no ol phenos

4723A13 KR PIL PIC spherulitic 24 3 swtl plag51 mm

(continued)


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by an assemblage of talc^tremolite^serpentineôpaqueoxides there is no fresh olivine present in the Karmutsenlavas onVancouver Island Plagioclase and clinopyroxenephenocrysts are absent in the high-MgO lavas Thecoarse-grained mafic rocks are characterized by sub-ophi-tic textures with an average grain size typically 41mmand are generally not glomeroporphyritic these rocks aremainly from the interiors of massive flows although somemay represent sillsSample preparation and analytical methods for major-

and trace-element and Sr^Nd^Hf^Pb isotopic composi-tions of the Karmutsen volcanic rocks are given in theAppendix

WHOLE -ROCK CHEMISTRYMajor- and trace-element compositionsThe most abundant type of volcanic rock in theKarmutsen Formation is tholeiitic basalt with a restrictedrange of major- and trace-element compositions The tho-leiitic basalts have similar compositions to the coarse-grained mafic rocks and both groups are distinct fromthe picrites and high-MgO basalts [Fig 6 picrites412wt MgO (LeBas 2000) high-MgO basalts8^12wt MgO] The tholeiitic basalts have lower MgO(57^77wt MgO) and higher TiO2 (14^22wt

TiO2) than the picrites (130^198wt MgO05^07wt TiO2) and high-MgO basalts (91^116wt MgO 05^08wt TiO2 Fig 6 Table 2) Almost allcompositions plot within the tholeiitic field in a total alka-lis vs silica plot although there has been substantial K lossin most samples from the Karmutsen Formation (seebelow) and the tholeiitic basalts generally have higherSiO2 Na2OthornK2O CaO and FeOT (total iron expressedas FeO) than the picrites The tholeiitic basalts also havenoticeably lower loss on ignition (LOI mean1713wt ) than the picrites (mean 54 08wt )and high-MgO basalts (mean 3815wt ) (Fig 6)reflecting the presence of abundant altered olivinephenocrysts in the latter groups Ni concentrations are sig-nificantly higher for the picrites (339^755 ppm) and high-MgO basalts (122^551ppm) than the tholeiitic basalts(58^125 ppm except for one anomalous sample) andcoarse-grained rocks (70^213 ppm) (Fig 6 Table 2) Ananomalous tholeiitic pillowed flow (two samples outlierin Tables 1 and 2) from near the picrite type locality atKeogh Lake and a mineralized sill (disseminated sulfide)from the basal sediment^sill complex at Schoen Lake aredistinguished by higher TiO2 and FeOT than the maingroup of tholeiitic basalts The tholeiitic basalts are similarin major-element composition to previously publishedresults for samples from the Karmutsen Formation how-ever the Keogh Lake picrites which encompass the

Table 1 Continued





5616A1 KR PIL PIC intergranular intersertal 25 1 ol52 mm

4723A2 KR PIL HI-MG spherulitic 0 3 swtl plag52mm no ol phenos

5614A3 KR PIL HI-MG spherulitic intrafasciculate 12 1 ol515mm swtl plag52 mm

5614A5 KR BRE HI-MG porphyritic ophimottled 13 2 ol52mm cpx52mm enc plag

5616A7 KR PIL HI-MG intersertal 2 2 ol52mm plag needles51 mm

4722A5 KR FLO OUTLIER intersertal 3 mottled very fg v small pl needles

5615A11 KR PIL OUTLIER intersertal 3 mottled very fg v small pl needles

5617A4 SL SIL MIN intersertal 5 3 fg

Sample number last digit of year month day initial sample station (except 93G171) MA Mount Arrowsmith SLSchoen Lake KR Karmutsen Range PIL pillow BRE breccia FLO flow SIL sill GAB gabbro THOL tholeiiticbasalt PIC picrite HI-MG high-MgO basalt CGcoarse-grained MIN mineralized sill glomero glomeroporphyriticOlivine modes for picrites are based on area calculations from scans (see lsquoOlivine accumulation in high-MgO and picriticlavasrsquo section and Fig 11) Visual alteration index is based primarily on degree of plagioclase alteration and presence ofsecondary minerals (1 least altered 3 most altered) Plagioclase phenocrysts are commonly altered to albite pumpellyiteand chlorite olivine is altered to talc tremolite and clinochlore (determined using the Rietveld method of X-ray powderdiffraction) clinopyroxene is unaltered FendashTi oxide is commonly replaced by sphene glcr glomerocrysts fg fine-grained cg coarse-grained oik oikocryst chad chadacryst enc enclosing swtl swallow-tail ol olivinepseudomorphs plag plagioclase cpx clinopyroxene ox oxides (includes ilmenite thorn titanomagnetite)


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+K2ONa2O TiO2

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Ni (ppm)

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CaO

alkalic

tholeiitic

Karmutsen Form

PicriteHigh-MgO basalt

Tholeiitic basaltCoarse-grained

(compiled data)

Pillowed flowMineralized sill

SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

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Fig 6 Whole-rock major-element Ni and LOI variation diagrams for the Karmutsen Formation New samples from this study (Table 2) areshown by symbols with black outlines (see legend) Previously published analyses are shown by small gray symbols without black outlines Theboundary of the alkaline and tholeiitic fields is that of MacDonald amp Katsura (1964) Total iron expressed as FeO LOI loss on ignition oxidesare plotted on an anhydrous normalized basis References for the 322 compiled analyses for the Karmutsen Formation are Surdam (1967)Kuniyoshi (1972) Muller et al (1974) Barker et al (1989) Lassiter et al (1995) Massey (1995a1995b)Yorath et al (1999) and G Nixon (unpublisheddata) It should be noted that the compiled dataset has not been filtered many of the samples with high SiO2 (452wt ) are probably notKarmutsen flood basalts but younger Bonanza basalts and andesites Three pillowed flow samples and a mineralized sill are distinguishedseparately because of their anomalous chemistry Coarse-grained samples are indicated separately Three tholeiitic basalt samples (4724A54718A5 4718A6) with416wt Al2O3 and4270 ppm Sr contain 10^25 modal of large plagioclase phenocrysts (7^8mm) or glomerocrysts(44mm)


10

Table 2 Major element (wt oxide) and trace element (ppm) abundances in whole-rock samples of Karmutsen basalts

Vancouver Island BC

Sample 4718A1 4718A2(1) 4718A2(2) 4718A5 4718A6 4718A7 4719A2 4719A3 4720A2 4720A3

Group THOL THOL THOL THOL THOL THOL THOL THOL THOL THOL

Area MA MA MA MA MA MA MA MA SL SL

Flow Pillow Pillow Pillow Flow Breccia Pillow Pillow Pillow Breccia Flow

UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890

Unnormalized major element oxides (wt )

SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911

Trace elements (ppm)

La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued

Sample 4720A4 4720A5 4720A8 4720A9 4721A1 4721A2 4721A3 4721A4 4721A5 4722A2(1)1


Area SL SL SL SL SL SL SL SL SL KR

Flow Flow Pillow Flow Flow Pillow Flow Flow Flow Flow Flow

UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued

Sample 4722A2(2)1 4722A2(3)1 4722A2(4)1 4723A10 4724A5 5614A10 5614A11 5614A13 5615A1 5615A8


Area KR KR KR KR SL KR KR KR KR KR

Flow Flow Flow Flow Flow Flow Flow Flow Flow Pillow Pillow

UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued

Sample 5615A10 5616A2 5618A1 5618A3 5618A4 4720A6 4720A7(1) 4720A7(2) 4720A10 4724A3

Group THOL THOL THOL THOL THOL CG CG CG CG CG

Area KR KR QI QI QI SL SL SL SL SL

Flow Pillow Flow Flow Pillow Breccia Flow Flow Flow Sill Flow

UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued

Sample 5614A14 5614A15 5615A5 5615A6 5616A3 5617A1 5617A5(1)1 5617A5(2)1 4722A4(1)1 4722A4(2)1

Group CG CG CG CG CG CG CG CG PIC PIC

Area KR KR KR KR KR SL SL SL KR KR

Flow Sill Flow Flow Sill Flow Sill Sill Sill Pillow Pillow

UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued

Sample 4722A4(3)1 4723A31 4723A41 4723A13(1)1 4723A13(2)1 5614A11 5615A71 5615A121 5616A11 93G171

Group PIC PIC PIC PIC PIC PIC PIC PIC PIC PIC

Area KR KR KR KR KR KR KR KR KR KR

Flow Pillow Pillow Pillow Pillow Pillow Pillow Pillow Pillow Pillow Pillow

UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4

Group HI-MG HI-MG HI-MG HI-MG OUTLIER OUTLIER OUTLIER MIN SIL

Area KR KR KR KR KR KR KR SL

Flow Pillow Pillow Breccia Pillow Flow Flow Pillow Sill

UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088

1Ni concentrations for these samples were determined by XRFTHOL tholeiitic basalt PIC picrite HI-MG high MgO basalt CG coarse-grained (sill or gabbro) MIN SIL mineralizedsill OUTLIER anomalous pillowed flow in plots MA Mount Arrowsmith SL Schoen Lake KR Karmutsen Range QIQuadra Island Sample locations are given using the Universal Transverse Mercator (UTM) coordinate system (NAD83zones 9 and 10) Analyses were performed at Activation Laboratory (ActLabs) Fe2O3

is total iron expressed as Fe2O3LOI loss on ignition All major elements Sr V and Y were measured by ICP quadrupole OES on solutions of fusedsamples Cu Ni Pb and Zn were measured by total dilution ICP Cs Ga Ge Hf Nb Rb Ta Th U Zr and REE weremeasured by magnetic-sector ICP on solutions of fused samples Co Cr and Sc were measured by INAA Blanks arebelow detection limit See Electronic Appendices 2 and 3 for complete XRF data and PCIGR trace element datarespectively Major elements for sample 93G17 are normalized anhydrous Sample 5615A7 was analyzed by XRFSamples from Quadra Island are not shown in figures


17

picritic and high-MgO basalt pillow lavas extend to20wt MgO (Fig 6 and references listed in thecaption)The tholeiitic basalts from the Karmutsen Range dis-

play a tight range of parallel light rare earth element(LREE)-enriched REE patterns (LaYbCNfrac14 21^24mean 2202) whereas the picrites and high-MgObasalts are characterized by sub-parallel LREE-depleted

patterns (LaYbCNfrac14 03^07 mean 06 02) with lowerREE abundances than the tholeiitic basalts (Fig 7)Tholeiitic basalts from the Schoen Lake and MountArrowsmith areas have similar REE patterns tosamples from the Karmutsen Range (Schoen Lake LaYbCNfrac14 21^26 mean 2303 Mount Arrowsmith LaYbCNfrac1419^25 mean 2204) and the coarse-grainedmafic rocks have similar REE patterns to the tholeiitic

Depleted MORB average(Salters amp Stracke 2004)

Schoen LakeSchoen Lake

Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e


Tholeiitic basaltCoarse-grained mafic rock


1

10

100

1

10

100

1

10

100

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu


01

1

10

100

1

10

100

1

10

100

Cs RbBa Th U K Nb Ta La Ce Pr Nd Sr Sm Zr Hf Ti Eu Gd Tb Dy Ho Y Er Yb Lu


La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Cs RbBa Th U K Nb Ta La Ce Pr Nd Sr Sm Zr Hf Ti Eu Gd Tb Dy Ho Y Er Yb Lu

Fig 7 Whole-rock REE and other incompatible-element concentrations for the Karmutsen Formation (a) (c) and (e) are chondrite-normal-ized REE patterns for samples from each of the three main field areas onVancouver Island (b) (d) and (f) are primitive mantle-normalizedtrace-element patterns for samples from each of the three main field areas All normalization values are from McDonough amp Sun (1995) Theclear distinction between LREE-enriched tholeiitic basalts and LREE-depleted picrites the effects of alteration on the LILE (especially loss ofK and Rb) and the different range for the vertical scale in (b) (extends down to 01) should be noted


18

basalts (LaYbCNfrac14 21^29 mean 2508) Two LREE-depleted coarse-grained mafic rocks from the SchoenLake area have similar REE patterns (LaYbCNfrac14 07) tothe picrites from the Keogh Lake area indicating that thisdistinctive suite of rocks is exposed as far south asSchoen Lake that is 75 km away (Fig 7) The anomalouspillowed flow from the Karmutsen Range has lower LaYbCN (13^18) than the main group of tholeiitic basaltsfrom the Karmutsen Range (Fig 7) The mineralized sillfrom the Schoen Lake area is distinctly LREE-enriched(LaYbCNfrac14 33) with the highest REE abundances(LaCNfrac14 940) of all Karmutsen samples this may reflectcontamination by adjacent sediment also evident in thin-section where sulfide blebs are cored by quartz (Greeneet al 2006)The primitive mantle-normalized trace-element pat-

terns (Fig 7) and trace-element variations and ratios(Fig 8) highlight the differences in trace-element

concentrations between the four main groups ofKarmutsen flood basalts onVancouver Island The tholeii-tic basalts from all three areas have relatively smooth par-allel trace-element patterns some samples have smallpositive Sr anomalies relative to Nd and Sm and manysamples have prominent negative K anomalies relative toU and Nb reflecting K loss during alteration (Fig 7) Thelarge ion lithophile elements (LILE) in the tholeiiticbasalts (mainly Rb and K not Cs) are depleted relativeto the high field strength elements (HFSE) and LREELILE segments especially for the Schoen Lake area(Fig 7d) are remarkably parallel The picrites andhigh-MgO basalts form a tight band of parallel trace-element patterns and are depleted in HFSE and LREEwith positive Sr anomalies and relatively low Rb Thecoarse-grained mafic rocks from the Karmutsen Rangehave identical trace-element patterns to the tholeiiticbasalts Samples from the Schoen Lake area have similar

000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)

Fig 8 Whole-rock trace-element concentrations and ratios for the Karmutsen Formation [except (b) which is vs wt MgO] (a) Nb vs Zr(b) NbLa vs MgO (c) Th vs Hf (d) Th vs U There is a clear distinction between the tholeiitic basalts and picrites in Nb and Zr both inconcentration and the slope of each trend


19

trace-element patterns to the Karmutsen Range except forthe two LREE-depleted coarse-grained mafic rocks andthe mineralized sill (Fig 7d)

Sr^Nd^Hf^Pb isotopic compositionsA total of 19 samples from the four main groups ofthe Karmutsen Formation were selected for radiogenicisotopic geochemistry on the basis of major- and trace-element variation stratigraphic position and geographicallocation The samples have overlapping age-correctedHf and Nd isotope ratios and distinct ranges of Sr isotopiccompositions (Fig 9) The tholeiitic basalts picriteshigh-MgO basalt and coarse-grained mafic rocks have

initial eHffrac14thorn87 to thorn126 and eNdfrac14thorn66 to thorn88 cor-rected for in situ radioactive decay since 230 Ma (Fig 9Tables 3 and 4) All the Karmutsen samples form a well-defined linear array in a Lu^Hf isochron diagram corre-sponding to an age of 24115 Ma (Fig 9) This is withinerror of the accepted age of the Karmutsen Formationand indicates that the Hf isotope systematics behaved as aclosed system since c 230 Ma The anomalous pillowedflow has similar initial eHf (thorn98) and slightly lower initialeNd (thorn62) compared with the other Karmutsen samplesThe picrites and high-MgO basalt have higher initial87Sr86Sr (070398^070518) than the tholeiitic basalts(initial 87Sr86Srfrac14 070306^070381) and the coarse-grained mafic rocks (initial 87Sr86Srfrac14 070265^070428)

05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf

Age=241 plusmn 15 Ma=+990 plusmn 064

176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)

Fig 9 Whole-rock Sr Nd and Hf isotopic compositions for the Karmutsen Formation (a) 143Nd144Nd vs 147Sm144Nd (b) 176Hf177Hf vs176Lu177Hf The slope of the best-fit line for all samples corresponds to an age of 24115 Ma (c) Initial eNd vs 87Sr86Sr Age-correction to230 Ma (d) LOI vs 87Sr86Sr (e) Initial eHf vs eNd Average 2 error bars are shown in a corner of each panel Complete chemical duplicatesshown inTables 3 and 4 (samples 4720A7 and 4722A4) are circled in each plot


20

overlap the ranges of the picrites and tholeiitic basalts(Fig 9 Table 3)The measured Pb isotopic compositions of the tholeiitic

basalts are more radiogenic than those of the picrites andthe most magnesian Keogh Lake picrites have the leastradiogenic Pb isotopic compositions The range ofinitial Pb isotope ratios for the picrites is206Pb204Pbfrac1417868^18580 207Pb204Pbfrac1415547^15562and 208Pb204Pbfrac14 37873^38257 and the range for thetholeiitic basalts is 206Pb204Pbfrac1418782^19098207Pb204Pbfrac1415570^15584 and 208Pb204Pbfrac14 37312^38587 (Fig 10 Table 5) The coarse-grained mafic rocksoverlap the range of initial Pb isotopic compositions forthe tholeiitic basalts with 206Pb204Pbfrac1418652^19155207Pb204Pbfrac1415568^15588 and 208Pb204Pbfrac14 38153^38735 One high-MgO basalt has the highest initial206Pb204Pb (19242) and 207Pb204Pb (15590) and thelowest initial 208Pb204Pb (37676) The Pb isotopic ratiosfor Karmutsen samples define broadly linearrelationships in Pb isotope plots The age-corrected Pb

isotopic compositions of several picrites have been affectedby U and Pb (andor Th) mobility during alteration(Fig 10)

ALTERAT IONThe Karmutsen basalts have retained most of their origi-nal igneous structures and textures however secondaryalteration and low-grade metamorphism have producedzeolitic- and prehnite^pumpellyite-bearing mineral assem-blages (Table 1 Cho et al 1987) Alteration and metamor-phism have primarily affected the distribution of the LILEand the Sr isotopic systematics The Keogh Lake picriteshave been affected more by alteration than the tholeiiticbasalts and have higher LOI (up to 55wt ) variableLILE and higher measured Sr Nd and Hf and lowermeasured Pb isotope ratios than the tholeiitic basalts Srand Pb isotope compositions for picrites and tholeiiticbasalts show a relationship with LOI (Figs 9 and 10)whereas Nd and Hf isotopic compositions do not correlate

Table 3 Sr and Nd isotopic compositions of Karmutsen basaltsVancouver Island BC

Sample Group Area Rb Sr 87Sr86Sr 2m87Rb86Sr 87Sr86Srt Sm Nd 143Nd144Nd 2m eNd

147Sm144Nd 143Nd144Ndt eNd(t)

(ppm) (ppm) 230 Ma (ppm) (ppm) 230 Ma

4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62

THOL tholeiitic basalt CG coarse-grained mafic rock PIC picrite HI-MG high-MgO basalt OUTLIER anomalouspillowed flow in plots KR Karmutsen Range SL Schoen Lake MA Mount Arrowsmith (dup) indicates completechemistry duplicate from the sample sample powder All isotopic and elemental analyses carried out at the PCIGR thecomplete trace element analyses are given in Electronic Appendix 3


21

with LOI (not shown) The relatively high apparent initialSr isotopic compositions for the high-MgO lavas (up to07052) probably resulted from post-magmatic loss of Rbor an increase in 87Sr86Sr through addition of seawater Sr(eg Hauff et al 2003) High-MgO lavas from theCaribbean plateau have similarly high 87Sr86Sr comparedwith basalts (Recurren villon et al 2002)The correction for in situdecay on initial Pb isotopic ratios has been affected bymobilization of U and Th (and Pb) in the whole-rockssince their formation A thorough acid leaching duringsample preparation was used that has been shown to effec-tively remove alteration phases (Weis et al 2006 NobreSilva et al in preparation) Whole-rock SmNd ratiosand age-correction of Nd isotopes may be affected bythe leaching procedure for submarine rocks older than50 Ma (Thompson et al 2008 Fig 9) there ishowever very little variation in Nd isotopic compositionsof the picrites or tholeiitic basalts and this system does notappear to be disturbed by alteration The HFSE abun-dances for tholeiitic and picritic basalts exhibit clear

linear correlations in binary diagrams (Fig 8) whereasplots of LILE vs HFSE are highly scattered (not shown)because of the mobility of some of the alkali and alkalineearth LILE (Cs Rb Ba K) and Sr for most samplesduring alterationThe degree of alteration in the Karmutsen samples does

not appear to be related to eruption environment or depthof burial Pillow rims are compositionally different frompillow cores (Surdam1967 Kuniyoshi1972) and aquagenetuffs are chemically different from isolated pillows withinpillow breccias however submarine and subaerial basaltsexhibit a similar degree of alterationThere is no clear cor-relation between the submarine and subaerial basalts andsome commonly used chemical alteration indices (eg BaRb vs K2OP2O5 Huang amp Frey 2005) There is also nodefinitive correlation between the petrographic alterationindex (Table 1) and chemical alteration indices although10 of 13 tholeiitic basalts with the highest K and LILEabundances have the highest petrographic alterationindex of three (seeTable 1)

Table 4 Hf isotopic compositions of Karmutsen basaltsVancouver Island BC

Sample Group Area Lu Hf 176Hf177Hf 2m eHf176Lu177Hf 176Hf177Hft eHf(t)

(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98

THOL tholeiitic basalt CG coarse-grained mafic rock PIC picrite HI-MG high-MgO basalt OUTLIER anomalouspillowed flow in plots KR Karmutsen Range SL Schoen Lake MA Mount Arrowsmith (dup) indicates completechemistry duplicate from the sample sample powder All isotopic and elemental analyses were carried out at the PCIGRthe complete trace element analyses are given in Electronic Appendix 3


22

OLIV INE ACCUMULAT ION INH IGH-MgO AND PICR IT IC LAVASGeochemical trends and petrographic characteristics indi-cate that accumulation of olivine played an important rolein the formation of the high-MgO basalts and picrites fromthe Keogh Lake area on northern Vancouver Island TheKeogh Lake samples show a strong linear correlation inplots of Al2O3 TiO2 ScYb and Ni vs MgO and many ofthe picrites have abundant clusters of olivine pseudomorphs(Table1 Fig11)There is a strong linear correlationbetween

modal per cent olivine and whole-rock magnesium contentmagnesium contents range between 10 and 19wt MgOand the proportion of olivine phenocrysts in these samplesvaries from 0 to 42 vol (Fig 11)With a few exceptionsboth the size range and median size of the olivine pheno-crysts in most samples are comparable The clear correla-tion between the proportion of olivine phenocrysts andwhole-rock magnesium contents indicates that accumula-tion of olivine was directly responsible for the high MgOcontents (410wt ) in most of the picritic lavas



Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2

Fig 10 Pb isotopic compositions of leached whole-rock samples measured by MC-ICP-MS for the Karmutsen Formation Error bars are smal-ler than symbols (a) Measured 207Pb204Pb vs 206Pb204Pb (b) Initial 207Pb204Pb vs 206Pb204Pb Age-correction to 230 Ma (c) Measured208Pb204Pb vs 206Pb204Pb (d) LOI vs 206Pb204Pb (e) Initial 208Pb204Pb vs 206Pb204Pb Complete chemical duplicates shown in Table 5(samples 4720A7 and 4722A4) are circled in each plot The dashed lines in (b) and (e) show the differences in age-corrections for two picrites(4723A4 4722A4) using the measured UTh and Pb concentrations for each sample and the age-corrections when concentrations are used fromthe two picrites (4723A3 4723A13) that appear to be least affected by alteration


23

DISCUSS IONThe compositional and spatial development of the eruptedlava sequences of the Wrangellia oceanic plateau onVancouver Island provide information about the evolutionof a mantle plume upwelling beneath oceanic lithospherein an analogous way to the interpretation of continentalflood basalts The Caribbean and Ontong Java plateausare the two primary examples of accreted parts of oceanicplateaus that have been studied to date and comparisonscan be made with the Wrangellia oceanic plateauHowever the Wrangellia oceanic plateau is a distinctiveoccurrence of an oceanic plateau because it formed on thecrust of a Devonian to Mississippian intra-oceanic islandarc overlain by Mississippian to Permian limestones andpelagic sediments The nature and thickness of oceaniclithospheric mantle are considered to play a fundamentalrole in the decompression and evolution of a mantleplume and thus the compositions of the erupted lavasequences (Greene et al 2008) The geochemical and

stratigraphic relationships observed in the KarmutsenFormation onVancouver Island and the focus of the subse-quent discussion sections provide constraints on (1) thetemperature and degree of melting required to generatethe primary picritic magmas (2) the composition of themantle source (3) the depth of melting and residual min-eralogy in the source region (4) the low-pressure evolutionof the Karmutsen tholeiitic basalts (5) the growth of theWrangellia oceanic plateau

Melting conditions and major-elementcomposition of the primary magmasThe primary magmas to most flood basalt provinces arebelieved to be picritic (eg Cox 1980) and they have beenfound in many continental and oceanic flood basaltsequences worldwide (eg Siberia Karoo Paranacurren Êtendeka Caribbean Deccan Saunders 2005) Near-pri-mary picritic lavas with low total alkali abundances

Table 5 Pb isotopic compositions of Karmutsen basaltsVancouver Island BC

Sample Group Area U Th Pb 206Pb 2m207Pb 2m

208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb

(ppm) (ppm) (ppm) 204Pb 204Pb 204Pb 204Pb 204Pb 204Pb 204Pbt204Pbt

204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24

require high-degree partial melting of the mantle source(eg Herzberg amp OrsquoHara 2002) The Keogh Lake picritesfrom northernVancouver Island are the best candidates foridentifying the least modified partial melts of the mantleplume source despite having accumulated olivine pheno-crysts and can be used to estimate conditions of meltingand the composition of the primary magmas for theKarmutsen FormationPrimary magma compositions mantle potential tem-

peratures and source melt fractions for the picritic lavas ofthe Karmutsen Formation were calculated from primitivewhole-rock compositions using PRIMELT1XLS software(Herzberg et al 2007) and are presented in Fig 12 andTable 6 A detailed discussion of the computationalmethod has been given by Herzberg amp OrsquoHara (2002)and Herzberg et al (2007) key features of the approachare outlined belowPrimary magma composition is calculated for a primi-

tive lava by incremental addition of olivine and compari-son with primary melts of mantle peridotite Lavas thathad experienced plagioclase andor clinopyroxene fractio-nation are excluded from this analysis All calculated pri-mary magma compositions are assumed to be derived byaccumulated fractional melting of fertile peridotite KR-4003 Uncertainties in fertile peridotite composition donot propagate to significant variations in melt fractionand mantle potential temperature melting of depletedperidotite propagates to calculated melt fractions that aretoo high but with a negligible error in mantle potential

temperature PRIMELT1XLS calculates the olivine liqui-dus temperature at 1atm which should be similar to theactual eruption temperature of the primary magmaand is accurate to 308C at the 2 level of confidenceMantle potential temperature is model dependent witha precision that is similar to the accuracy of the olivineliquidus temperature (C Herzberg personal communica-tion 2008)With regard to the evidence for accumulated olivine in

the Keogh Lake picrites it should not matter whether themodeled lava composition is aphyric or laden with accu-mulated olivine phenocrysts PRIMELT1 computes theprimary magma composition by adding olivine to a lavathat has experienced olivine fractionation in this way itinverts the effects of fractional crystallization The onlyrequirement is that the olivine phenocrysts are not acci-dental or exotic to the lava compositions Support for thisprocedure can be seen in the calculated olivine liquid-line-of-descent shown by the curved arrays with 5 olivineaddition increments (Fig 12c) Fractional crystallization ofolivine from model primary magmas having 85^95wt FeO and 153^175wt MgO will yield arrays of deriva-tive liquids and randomly sorted olivines that in most butnot all cases connect the picrites and high-MgO basalts Anewer version of the PRIMELT software (Herzberg ampAsimow 2008) can perform olivine addition to and sub-traction from lavas with highly variably olivine phenocrystcontents and yields results that converge with those shownin Fig 12

Fig 11 Relationship between abundance of olivine phenocrysts and whole-rock MgO contents for the Keogh Lake picrites (a) Tracings ofolivine grains (gray) in six high-MgO samples made from high resolution (2400 dpi) scans of petrographic thin-sections Scale bars represent10mm sample numbers are indicated at the upper left (b) Modal olivine vs whole-rock MgO Continuous line is the best-fit line for 10 high-MgO samplesThe areal proportion of olivine was calculated from raster images of olivine grains using ImageJ image analysis software whichprovides an acceptable estimation of the modal abundance (eg Chayes 1954)


25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS

Liquid compositions Fertile peridotite source

Accumulated Fractional Melting model

Gray lines = final melting pressure

L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

Thick black lines = initial melting pressure

Dashed lines = melt fraction

Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel

SolidusGarnet Peridotite

7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2

Peridotite Partial Melts

Thick black line = initial melting pressureGray lines = final melting pressure

Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)

Karmutsen flood basaltsOlivine addition modelOlivine addition (5 increment)Primary magma

PicriteHigh-MgO basaltTholeiitic basalt

(a)

(b)

800 850 900

910

920

930

940

950

Karmutsen flood basalts

Olivine addition modelOlivine addition (5 increment)Primary magma

Gray lines = Fo contents of olivine

Fig 12 Estimated primary magma compositions for three Keogh Lake picrites and high-MgO basalts (samples 4723A4 4723A135616A7) using the forward and inverse modeling technique of Herzberg et al (2007) Karmutsen compositions and modeling results areoverlain on diagrams provided by C Herzberg (a) Whole-rock FeO vs MgO for Karmutsen samples from this study Total iron estimatedto be FeO is 090 Gray lines show olivine compositions that would precipitate from liquid of a given MgO^FeO composition Black lineswith crosses show results of olivine addition (inverse model) using PRIMELT1 (Herzberg et al 2007) Gray field highlights olivinecompositions with Fo contents of 91^92 predicted to precipitate (b) FeO vs MgO showing Karmutsen lava compositions and results ofa forward model for accumulated fractional melting of fertile peridotite KR-4003 (Kettle River Peridotite Walter 1998) (c) SiO2 vsMgO for Karmtusen lavas and model results (d) CaO vs MgO showing Karmtusen lava compositions and model results To brieflysummarize the technique [see Herzberg et al (2007) for complete description] potential parental magma compositions for the high-MgOlava series were selected (highest MgO and appropriate CaO) and using PRIMELT1 software olivine was incrementally added tothe selected compositions to show an array of potential primary magma compositions (inverse model) Then using PRIMELT1 theresults from the inverse model were compared with a range of accumulated fractional melts for fertile peridotite derived fromparameterization of the experimental results for KR-4003 from Walter (1998) forward model Herzberg amp OrsquoHara (2002) A melt fractionwas sought that was unique to both the inverse and forward models (Herzberg et al 2007) A unique solution was found when there was a com-mon melt fraction for both models in FeO^MgO and CaO^MgOÂl2O3^SiO2 (CMAS) projection space This modeling assumes thatolivine was the only phase crystallizing and ignores chromite precipitation and possible augite fractionation in the mantle (Herzbergamp OrsquoHara 2002) Results are best for a residue of spinel lherzolite (not pyroxenite) The presence of accumulated olivine in samples ofthe Keogh Lake picrites used as starting compositions does not significantly affect the results because we are modeling addition of olivine(see text for further description) The tholeiitic basalts cannot be used for modeling because they are all saturated in plagthorn cpxthornolThick black line for initial melting pressure at 4 GPa is not shown in (c) for clarity Gray area in (a) indicates parental magmas thatwill crystallize olivine with Fo 91^92 at the surface Dashed lines in (c) indicate melt fraction Solidi for spinel and garnet peridotite arelabelled in (c)


26

The PRIMELT1 results indicate that if the Karmutsenpicritic lavas were derived from accumulated fractionalmelting of fertile peridotite the primary magmas wouldhave contained 15^17wt MgO and 10wt CaO(Fig 12 Table 6) formed from 23^27 partial meltingand would have crystallized olivine with a Fo content of 91 (Fig 12 Table 6) Calculated mantle temperatures forthe Karmutsen picrites (14908C) indicate melting ofanomalously hot mantle (100^2008C above ambient) com-pared with ambient mantle that produces mid-ocean ridgebasalt (MORB 1280^14008C Herzberg et al 2007)which initiated between 3 and 4 GPa Several picritesappear to be near-primary melts and required very littleaddition of olivine (eg sample 93G171 with measured158wt MgO) These temperature and melting esti-mates of the Karmutsen picrites are consistent withdecompression of hot mantle peridotite in an actively con-vecting plume head (ie plume initiation model) Threesamples (picrite 5614A1 and high-MgO basalts 5614A3and 5614A5) are lower in iron than the other Karmutsenlavas with FeO in the 65^80wt range (Fig 12c) andhave MgO and FeO contents that are similar to primitiveMORB from the Sequeiros fracture zone of the EastPacific Rise (EPR Perfit et al 1996) These samples

however differ from EPR MORB in having higher SiO2

and lower Al2O3 and they are restricted geographicallyto one area (Sara Lake Fig 2)We therefore have evidence for primary magmas with

MgO contents that range from a possible low of 110wt to as high as 174wt with inferred mantle potential tem-peratures from 1340 to 15208C This is similar to the rangedisplayed by lavas from the Ontong Java Plateau deter-mined by Herzberg (2004) who found that primarymagma compositions assuming a peridotite sourcewould contain 17wt MgO and 10wt CaO(Table 6) and that these magmas would have formed by27 melting at a mantle potential temperature of15008C (first melting occurring at 36 GPa) Fitton ampGodard (2004) estimated 30 partial melting for theOntong Java lavas based on the Zr contents of primarymagmas of Kroenke-type basalt calculated by incrementaladdition of equilibrium olivine However if a considerableamount of eclogite was involved in the formation of theOntong Java plateau magmas the excess temperatures esti-mated by Herzberg et al (2007) may not be required(Korenaga 2005) The variability in mantle potential tem-perature for the Keogh Lake picrites is also similar to thewide range of temperatures that have been calculated for

Table 6 Estimated primary magma compositions for Karmutsen basalts and other oceanic plateaus or islands

Sample 4723A4 4723A13 5616A7 93G171 Average OJP Mauna Keay Gorgonaz

wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606

Fo content (olivine) 912 912 916 912 913 905 914 906

Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18

Ontong Java primary magma composition for accumulated fraction melting (AFM) from Herzberg (2004)yMauna Kea primary magma composition is average of four samples of Herzberg (2006 table 1)zGorgona primary magma composition for AFM for 1F fertile source from Herzberg amp OrsquoHara (2002 table 4)Total iron estimated to be FeO is 090


27

lavas from single volcanoes in the Galapagos Hawaii andelsewhere by Herzberg amp Asimow (2008) Those workersinterpreted the range to reflect the transport of magmasfrom both the cool periphery and the hotter axis of aplume A thermally heterogeneous plume will yield pri-mary magmas with different MgO contents and the rangeof primary magma compositions and their inferred mantlepotential temperatures for Karmutsen lavas may reflectmelting from different parts of the plume

Source of the Karmutsen Formation lavasThe Sr^Nd^Hf^Pb isotopic compositions of theKarmutsen volcanic rocks on Vancouver Island indicatethat they formed from plume-type mantle containing adepleted component that is compositionally similar to butdistinct from other oceanic plateaus that formed in thePacific Ocean (eg Ontong Java and Caribbean Fig 13)Trace element and isotopic constraints can be used to testwhether the depleted component of the KarmutsenFormation was intrinsic to the mantle plume and distinctfrom the source of MORB or the result of mixing or invol-vement of ambient depleted MORB mantle with plume-type mantle The Karmutsen tholeiitic basalts have initialeNd and

87Sr86Sr ratios that fall within the range of basaltsfrom the Caribbean Plateau (eg Kerr et al 1996 1997Hauff et al 2000 Kerr 2003) and a range of Hawaiian iso-tope data (eg Frey et al 2005) and lie within and abovethe range for the Ontong Java Plateau (Tejada et al 2004Fig 13a) Karmutsen tholeiitic basalts with the highest ini-tial eNd and lowest initial 87Sr86Sr lie within and justbelow the field for age-corrected northern EPR MORB at230 Ma (eg Niu et al1999 Regelous et al1999) Initial Hfand Nd isotopic compositions for the Karmutsen samplesare noticeably offset to the low side of the ocean islandbasalt (OIB) array (Vervoort et al 1999) and lie belowand slightly overlap the low eHf end of fields for Hawaiiand the Caribbean Plateau (Fig 13c) the Karmutsen sam-ples mostly fall between and slightly overlap a field forage-corrected Pacific MORB at 230 Ma and Ontong Java(Mahoney et al 1992 1994 Nowell et al 1998 Chauvel ampBlichert-Toft 2001) Karmutsen lava Pb isotope ratios over-lap the broad range for the Caribbean Plateau and thelinear trends for the Karmutsen samples intersect thefields for EPR MORB Hawaii and Ontong Java in208Pb^206Pb space but do not intersect these fields in207Pb^206Pb space (Fig 13d and e) The more radiogenic207Pb204Pb for a given 206Pb204Pb of the Karmutsenbasalts requires high UPb ratios at an ancient time when235U was abundant similar to the Caribbean Plateau andenriched in comparison with EPR MORB Hawaii andOntong JavaThe low eHf^low eNd component of the Karmutsen

basalts that places them below the OIB mantle array andpartly within the field for age-corrected Pacific MORBcan form from low ratios of LuHf and high SmNd over

time (eg Salters amp White 1998) MORB will develop aHf^Nd isotopic signature over time that falls below themantle array Low LuHf can also lead to low 176Hf177Hffrom remelting of residues produced by melting in theabsence of garnet (eg Salters amp Hart 1991 Salters ampWhite 1998) The Hf^Nd isotopic compositions of theKarmutsen Formation indicate the possible involvementof depleted MORB mantle however similar to Iceland(Fitton et al 2003) Nb^Zr^Y variations provide a way todistinguish between a depleted component within theplume and a MORB-like component The Karmutsenbasalts and picrites fall within the Iceland array and donot overlap the MORB field in a logarithmic plot of NbYvs ZrY (Fig 13b) using the fields established by Fittonet al (1997) Similar to the depleted component within theCaribbean Plateau (Thompson et al 2003) the trend ofHf^Nd isotopic compositions towards Pacific MORB-likecompositions is not followed by MORB values in Nb^Zr^Y systematics and this suggests that the depleted compo-nent in the source of the Karmutsen basalts is distinctfrom the source of MORB and probably an intrinsic partof the plume The relatively radiogenic Pb isotopic ratiosand REE patterns distinct from MORB also support thisinterpretationTrace-element characteristics suggest the possible invol-

vement of sub-arc lithospheric mantle in the generation ofthe Karmutsen picrites Lassiter et al (1995) suggested thatmixing of a plume-type source with eNdthorn 6 to thorn 7 witharc material with low NbTh could reproduce the varia-tions observed in the Karmutsen basalts however theyconcluded that the absence of low NbLa ratios in theirsample of tholeiitic basalts restricts the amount of arc litho-sphere involved The study of Lassiter et al (1995) wasbased on major and trace element and Sr Nd and Pb iso-topic data for a suite of 29 samples from Buttle Lake in theStrathcona Provincial Park on central Vancouver Island(Fig 1) Whereas there are no clear HFSE depletions inthe Karmutsen tholeiitic basalts the low NbLa (and TaLa) of the Karmutsen picritic lavas in this study indicatethe possible involvement of Paleozoic arc lithosphere onVancouver Island (Fig 8)

REE modeling dynamic melting andsource mineralogyThe combined isotopic and trace-element variations of thepicritic and tholeiitic Karmutsen lavas indicate that differ-ences in trace elements may have originated from differentmelting histories For example the LuHf ratios of theKarmutsen picritic lavas (mean 008) are considerablyhigher than those in the tholeiitic basalts (mean 002)however the small range of overlapping initial eHf valuesfor the two lava suites suggests that these differences devel-oped during melting within the plume (Fig 9b) Below wemodel the effects of source mineralogy and depth of


28

melting on differences in trace-element concentrations inthe tholeiitic basalts and picritesDynamic melting models simulate progressive decom-

pression melting where some of the melt fraction isretained in the residue and only when the degree of partialmelting is greater than the critical mass porosity and the

source becomes permeable is excess melt extracted fromthe residue (Zou1998) For the Karmutsen lavas evolutionof trace element concentrations was simulated using theincongruent dynamic melting model developed by Zou ampReid (2001) Melting of the mantle at pressures greater than1 GPa involves incongruent melting (eg Longhi 2002)

OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)

Karmutsen tholeiitic basalt

HawaiiOntong JavaCaribbean Plateau

Karmutsen high-MgO lava

high-MgO lavasKarmutsen

1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb

Karmutsen Formation (initial)


East Pacific Rise

Karmutsen Formation (measured)

Juan de FucaGorda

ε Nd

(initial)

Karmutsen Formation (different age-correction for 3 picrites)

(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6

Fig 13 Comparison of age-corrected (230 Ma) Sr^Nd^Hf^Pb isotopic compositions for Karmutsen flood basalts onVancouver Island withage-corrected OIB and MORB and Nb^Zr^Y variation (a) Initial eNd vs 87Sr86Sr (b) NbYand ZrY variation (after Fitton et al 1997)(c) Initial eHf vs eNd (d) Measured and initial 207Pb204Pb vs 206Pb204Pb (e) Measured and initial 208Pb204Pb vs 206Pb204Pb References fordata sources are listed in Electronic Appendix 4 Most of the compiled data were extracted from the GEOROC database (httpgeorocmpch-mainzgwdgdegeoroc) OIB array line in (c) is fromVervoort et al (1999) EPR East Pacific Rise Several high-MgO samples affected bysecondary alteration were not plotted for clarity in Pb isotope plots Estimation of fields for age-corrected Pacific MORB and EPR at 230 Mawere made using parent^daughter concentrations (in ppm) from Salters amp Stracke (2004) of Lufrac14 0063 Hffrac14 0202 Smfrac14 027 Ndfrac14 071Rbfrac14 0086 and Srfrac14 836 In the NbYvs ZrYplot the normal (N)-MORB and OIB fields not including Icelandic OIB are from data com-pilations of Fitton et al (1997 2003) The OIB field is data from 780 basalts (MgO45wt ) from major ocean islands given by Fitton et al(2003) The N-MORB field is based on data from the Reykjanes Ridge EPR and Southwest Indian Ridge from Fitton et al (1997) The twoparallel gray lines in (b) (Iceland array) are the limits of data for Icelandic rocks


29

with olivine being produced during the reactioncpxthornopxthorn spfrac14meltthornol for spinel peridotites The mod-eling used coefficients for incongruent melting reactionsbased on experiments on lherzolite melting (eg Kinzleramp Grove 1992 Longhi 2002) and was separated into (1)melting of spinel lherzolite (2) two combined intervals ofmelting for a garnet lherzolite (gt lherz) and spinel lher-zolite (sp lherz) source (3) melting of garnet lherzoliteThe model solutions are non-unique and a range indegree of melting partition coefficients melt reactioncoefficients and proportion of mixed source componentsis possible to achieve acceptable solutions (see Fig 14 cap-tion for description of modeling parameters anduncertainties)The LREE-depleted high-MgO lavas require melting of

a depleted spinel lherzolite source (Fig 14a) The modelingresults indicate a high degree of melting (22^25) similarto the results from PRIMELT1 based on major-elementvariations (discussed above) of a LREE-depleted sourceThe high-MgO lavas lack a residual garnet signature Theenriched tholeiitic basalts involved melting of both garnetand spinel lherzolite and represent aggregate melts pro-duced from continuous melting throughout the depth ofthe melting column (Fig 14b) Trace-element concentra-tions in the tholeiitic and picritic lavas are not consistentwith low-degree melting of garnet lherzolite alone(Fig 14c) The modeling results indicate that the aggregatemelts that formed the tholeiitic basalts would haveinvolved lesser proportions of enriched small-degreemelts (1^6 melting) generated at depth and greateramounts of depleted high-degree melts (12^25) gener-ated at lower pressure (a ratio of garnet lherzolite tospinel lherzolite melt of 14 provides the best fits seeFig 14b and description in figure caption) The totaldegree of melting for the tholeiitic basalts was high(23^27) similar to the degree of partial melting in thespinel lherzolite facies for the primary melts that eruptedas the Keogh Lake picrites of a source that was also prob-ably depleted in LREE

1

10

100


1

10

100


(c)

1

10

100


Melting of garnet lherzolite

High-MgO lavas

Melting of spinel lherzolite

source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting

Melting of garnet lherzoliteand spinel lherzolite

x gt lherz + 4x sp lherz

5 meltingx gt lherz + 4x sp lherz

Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)

Fig 14 Trace-element modeling results for incongruent dynamicmantle melting for picritic and tholeiitic lavas from the KarmutsenFormation Three steps of modeling are shown (a) melting of spinellherzolite compared with high-MgO lavas (b) melting of garnet lher-zolite and spinel lherzolite compared with tholeiitic lavas (c) meltingof garnet lherzolite compared with tholeiitic and picritic lavasShaded fields in each panel for tholeiitic basalts and picrites arelabeled Patterns with symbols in each panel are modeling results(patterns are 5 melting increments in (a) and (b) and 1 incre-ments in (c) PM primitive mantle DM depleted MORB mantle gtlherz garnet lherzolite sp lherz spinel lherzolite In (b) the ratios ofper cent melting for garnet and spinel lherzolite are indicated (x gtlherzthorn 4x sp lherz means that for 5 melting 1 melt in garnetfacies and 4 melt in spinel facies where x is per cent melting in theinterval of modeling) The ratio of the respective melt proportions inthe aggregate melt (x gt lherzthorn 4x sp lherz) was kept constant andthis ratio of melt contribution provided the best fit to the data Arange of proportion of source components (07DMthorn 03PM to

09DMthorn 01PM) can reproduce the variation in the high-MgOlavas Melting modeling uses the formulation of Zou amp Reid (2001)an example calculation is shown in their Appendix PM fromMcDonough amp Sun (1995) and DM from Salters amp Stracke (2004)Melt reaction coefficients of spinel lherzolite from Kinzler amp Grove(1992) and garnet lherzolite fromWalter (1998) Partition coefficientsfrom Salters amp Stracke (2004) and Shaw (2000) were kept constantSource mineralogy for spinel lherzolite (018cpx027opx052ol003sp) from Kinzler (1997) and for garnet lherzolite(034cpx008opx053ol005gt) from Salters amp Stracke (2004) Arange of source compositions for melting of spinel lherzolite(07DMthorn 03PM to 03DMthorn 07PM) reproduce REE patternssimilar to those of the high-MgO lavas with best fits for 22ndash25melting and 07DMthorn 03PM source composition Concentrationsof tholeiitic basalts cannot be reproduced from an entirelyprimitive or depleted source


30

The uncertainty in the composition of the source in thespinel lherzolite melting model for the high-MgO lavasprecludes determining whether the source was moredepleted in incompatible trace elements than the source ofthe tholeiitic lavas (see Fig 14 caption for description) It ispossible that early high-pressure low-degree melting left aresidue within parts of the plume (possibly the hotter inte-rior portion) that was depleted in trace elements (egElliott et al 1991) further decompression and high-degreemelting of such depleted regions could then have generatedthe depleted high-MgO Karmutsen lavas Shallow high-degree melting would preferentially sample depletedregions whereas deeper low-degree melting may notsample more refractory depleted regions (eg CaribbeanEscuder-Viruete et al 2007) The picrites lie at the highend of the range of Nd isotopic compositions and havelow NbZr similar to depleted Icelandic basalts (Fittonet al 2003) therefore the picrites may represent the partsof the mantle plume that were the most depleted prior tothe initiation of melting As Fitton et al (2003) suggestedthese depleted melts may only rarely be erupted withoutcombining with more voluminous less depleted melts andthey may be detected only as undifferentiated small-volume flows like the Keogh Lake picrites within theKarmutsen Formation on Vancouver IslandDecompression melting within the mantle plume initiatedwithin the garnet stability field (35^25 GPa) at highmantle potential temperatures (Tp414508C) and pro-ceeded beneath oceanic arc lithosphere within the spinelstability field (25^09 GPa) where more extensivedegrees of melting could occur

Magmatic evolution of Karmutsentholeiitic basaltsPrimary magmas in large igneous provinces leave exten-sive coarse-grained cumulate residues within or below thecrust these mafic and ultramafic plutonic sequences repre-sent a significant proportion of the original magma thatpartially crystallized at depth (eg Farnetani et al 1996)For example seismic and petrological studies of OntongJava (eg Farnetani et al 1996) combined with the use ofMELTS (Ghiorso amp Sack 1995) indicate that the volcanicsequence may represent only 40 of the total magmareaching the Moho Neal et al (1997) estimated that30^45 fractional crystallization took place for theOntong Java magmas and produced cumulate thicknessesof 7^14 km corresponding to 11^22 km of flood basaltsdepending on the presence of pre-existing oceanic crustand the total crustal thickness (25^35 km) Interpretationsof seismic velocity measurements suggest the presence ofpyroxene and gabbroic cumulates 9^16 km thick beneaththe Ontong Java Plateau (eg Hussong et al 1979)Wrangellia is characterized by high crustal velocities in

seismic refraction lines which is indicative of mafic

plutonic rocks extending to depth beneath VancouverIsland (Clowes et al 1995)Wrangellia crust is 25^30 kmthick beneath Vancouver Island and is underlain by astrongly reflective zone of high velocity and density thathas been interpreted as a major shear zone where lowerWrangellia lithosphere was detached (Clowes et al 1995)The vast majority of the Karmutsen flows are evolved tho-leiitic lavas (eg low MgO high FeOMgO) indicating animportant role for partial crystallization of melts at lowpressure and a significant portion of the crust beneathVancouver Island has seismic properties that are consistentwith crystalline residues from partially crystallizedKarmutsen magmas To test the proportion of the primarymagma that fractionated within the crust MELTS(Ghiorso amp Sack 1995) was used to simulate fractionalcrystallization using several estimated primary magmacompositions from the PRIMELT1 modeling results Themajor-element composition of the primary magmas couldnot be estimated for the tholeiitic basalts because of exten-sive plagthorn cpxthornol fractionation and thus the MELTSmodeling of the picrites is used as a proxy for the evolutionof major elements in the volcanic sequence A pressure of 1kbar was used with variable water contents (anhydrousand 02wt H2O) calculated at the quartz^fayalite^magnetite (QFM) oxygen buffer Experimental resultsfrom Ontong Java indicate that most crystallizationoccurs in magma chambers shallower than 6 km deep(52 kbar Sano amp Yamashita 2004) however some crys-tallization may take place at greater depths (3^5 kbarFarnetani et al 1996)A selection of the MELTS results are shown in Fig 15

Olivine and spinel crystallize at high temperature until15^20wt of the liquid mass has fractionated and theresidual magma contains 9^10wt MgO (Fig 15f) At1235^12258C plagioclase begins crystallizing and between1235 and 11908C olivine ceases crystallizing and clinopyr-oxene saturates (Fig 15f) As expected the addition of clin-opyroxene and plagioclase to the crystallization sequencecauses substantial changes in the composition of the resid-ual liquid FeO and TiO2 increase and Al2O3 and CaOdecrease while the decrease in MgO lessens considerably(Fig 15) The near-vertical trends for the Karmutsen tho-leiitic basalts especially for CaO do not match the calcu-lated liquid-line-of-descent very well which misses manyof the high-CaO high-Al2O3 low-FeO basalts A positivecorrelation between Al2O3CaO and SrNd indicates thataccumulation of plagioclase played a major role in the evo-lution of the tholeiitic basalts (Fig 15g) Increasing thecrystallization pressure slightly and the water content ofthe melts does not systematically improve the match ofthe MELTS models to the observed dataThe MELTS results indicate that a significant propor-

tion of the crystallization takes place before plagioclase(15^20 crystallization) and clinopyroxene (35^45


31

crystallization) join the crystallization sequence Theseresults suggest that445 crystallization of the primarymagmas occurred (estimated from the residual liquid percent in Fig 15f) and if the original flood basalt stratigra-phy on Vancouver Island was 6 km thick at least anequivalent amount of complementary plutonic rocksshould have crystallized The Karmutsen basalts and theirplutonic residues thus represent a significant addition ofcrust (perhaps 412 km thickness) previously thickenedduring the formation of the underlying Paleozoic arc

Growth of the Wrangellia oceanic plateauon Vancouver IslandThe extrusive part of the Wrangellia oceanic plateau onVancouver Island was constructed in a three-layersequence of mostly tholeiitic basalts with a restrictedrange of composition (Fig 16) The plateau overliesDevonian to Mississippian arc volcanic sequences andmarine sediments of Mississippian to Permian ages thatare intruded by gabbroic rocks related to the flood basaltsThe volcanic stratigraphy of theWrangellia plateau formed

00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50

percent of total mass

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

) Mineral proportions

Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp

Plag+Ol+Sp Plag+Cpx+Sp

02 wt H2O

no H2O

Residual liquid and crystallizing phases

(f)

0102030405060708090100

plagioclaseaccumulation


plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)

Fig 15 Forward fractional crystallization modeling results for major elements from MELTS (Ghiorso amp Sack 1995) compared with picriticand tholeiitic lavas from the Karmutsen Formation (a^d) Major-element compositions of residual liquids compared with Karmutsen lavacompositions For clarity the results are shown only for one starting composition (open circle) using the composition of the estimated primarymagma for the high-MgO lava series from the modeling technique of Herzberg et al (2007) for sample 4723A13 as shown in Fig 12 The esti-mated primary magmas for samples 4723A3 and 93G171 yield similar results A pressure of 1 kbar was used with no H2O and 02wt H2Ocalculated at QFM black line is anhydrous and grey line is 02wt H2OThe end-point for the anhydrous result is at 78 fractionation and11308C and the end-point for the result with 02wt H2O is 75 fractionation and11108C (e) Mineral proportions of crystallized phases fromone MELTrun (sample 4723A13) with no H2O (f) Per cent residual liquid vs temperature labelled with intervals of crystallizing phases (g)Al2O3CaO vs SrNd for the tholeiitic basalts


32

in a single eruptive phase (c 231^225 Ma) as an emergentbasalt sequence during a deeper-water shallow-water andsubaerial stage and subsided below sea level relativelysoon after its formation (Fig 16) The deeper-water stagecontains pillowed and massive submarine flows (3000mthick) that built up the submarine volcanic edifice from theseafloor The lowest pillow basalts were emplaced onunconsolidated and lithified fine-grained siliciclastic andcarbonaceous sediments containing Daonella beds(c 235^232 Ma) that are intruded by abundantKarmutsen mafic sills (Fig 16a) The different pillowedand massive submarine flows resulted primarily from dif-ferent effusive rates and local topography Some of themassive submarine flows commonly recognized by radiat-ing columnar jointing represent master tubes for the deliv-ery of lava to distal parts of submarine flow fields Thepillowed flows which commonly have uneven topography

in modern sequences may have served as levees to themassive submarine flows rather than allowing unob-structed spreading and inflation typical of the massive sub-aerial flows that form on shallow slopes in continentalflood basalt provinces (eg Self et al 1997) The rapid suc-cession of flows is evident by the near absence of sedimentbetween submarine flows Minor volumes of picritic pillowlavas occur in the upper part of the pillowed flow sequencein areas of the plateau exposed on northern VancouverIsland (Fig 16 Nixon et al 2008)The growth of the plateau in shallow water led to

emplacement of an increasing proportion of volcaniclastics(pillow breccias and hyaloclastites) that accumulated up to1500m thick in some areas (Fig 16b Nixon et al 2008)Horizons of pillowed flows occur locally within the volca-niclastic stratigraphy Sedimentary structures (eg gradedbedding fluidization structures) and petrographic textures

Late Devonian-Mississippian arc

Daonella beds

Middle Triassic

deeper water


pillowed flows massive submarine

flows

pillow brecciahyaloclastiteshallow water

~4 km

~6 km

Late Triassic limestoneinterflow limestonelenses

Karmutsen Formation

mafic intrusions sediment-sill complex

Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows

Late Devonian-Mississippian arc Late Devonian-Mississippian arc

picritic pillow basalts

Miss to Permian marine sediments

sills

Fig 16 Growth of the Wrangellia oceanic plateau onVancouver Island (a) Deep-water eruptive phase of pillowed and massive submarineflows with almost no intervening sediments onto MiddleTriassic shale containing Daonella beds (c 235^232 Ma) The basement of the plateauis composed of Devonian to Mississippian arc sequences overlain by Mississippian to Permian carbonates and siliciclastic sediments(b) Shallow-water flow emplacement with increasing proportion of volcaniclastics resulted primarily from cooling^contraction granulationPicritic pillow basalts occur primarily near the transition between pillowed submarine flows and volcaniclastic units Pillowed and massiveflows occur locally within the volcaniclastic unit (c) Emergent stage of growth consists of overlapping subaerial flow fields similar to continen-tal flood basalts with pahoehoe flow structures Multi-tiered columnar jointing occurrs locally in response to ponding of flows (eg Bondre et al2004) Interflow carbonate deposits and plagioclase megacrystic flows developed locally during the waning stage of volcanism (d) Post-volcanicsubsidence and deposition of Late Carnian to Norian (c 212^223 Ma) platform carbonates on top of the plateau Units are labeled in the dia-grams Thicknesses of the underlying units are not to scale


33

within the volcaniclastic rocks indicate formation primar-ily via cooling^contraction granulation magma^water^steam interaction autobrecciation resedimentation andmass-wasting rather than pyroclastic eruption (Nixonet al 2008)A broad subaerial platform was constructed by emplace-

ment of subaerial lava flows during an emergent subaerialstage (Fig 16c) The subaerial unit predominantly com-prises well-layered sheet flows that formed in a similarway to continental flood basalts as hundred(s) of pahoehoeflow fields erupted on shallow slopes (Self et al 1997) how-ever volcaniclastic and pillowed flow units are locally pre-sent mostly in the upper parts of the stratigraphyLocalized ponding of flows led to the formation of multi-tiered columnar jointing in some subaerial flows (egBondre et al 2004) As volcanism waned local interflowcarbonate deposits developed and plagioclase megacrysticflows were erupted Subsidence of the plateau is recordedby the interflow lenses and deposits of platform carbonates(40^1500m thick) on top of the Karmutsen basalts thatcontain Late Carnian to Early Norian fossils (Fig 16d c216^227 Ma Nixon et al 2008)The evolution of the internal architecture of the

Wrangellia oceanic plateau was primarily related to theconditions of emplacement (ie water depth and eruptionenvironment) There does not appear to have been a sys-tematic coincident evolution or shift of lava compositionsonVancouver Island as has been recognized in most con-tinental flood basalts and parts of the Wrangellia oceanicplateau in Alaska and Yukon (Greene et al 2008 2009)In general with the exception of the picritic pillow lavasin the submarine stratigraphy and local variations betweenhigh-MgO and tholeiitic lavas there are no significantcompositional differences between lavas erupted duringthe different stages of growth of the plateau (ie submarineand subaerial flows) nor are substantial compositional dif-ferences generally found between massive submarine flowsin contact with pillowed flows tholeiitic basalt flows nearthe base of the Karmutsen Formation are compositionallysimilar to flows sampled near the top of the volcanicsequence Where it was possible to sample continuous sec-tions of volcanic stratigraphy greater than several hun-dreds of meters (eg Keogh^Maynard Lake area west ofthe Karmutsen Range Fig 2) there is no clear relationshipbetween stratigraphic position and compositionalvariation

CONCLUSIONSThe Karmutsen Formation covers extensive areas ofVancouver Island (20 000 km2) and forms part of a largeoceanic plateau erupted over a geologically short interval(c 225^231 Ma) The tripartite volcanic stratigraphyexposed on Vancouver Island is at least 6 km thick andcomprises a succession of submarine flows volcaniclastic

deposits and massive subaerial flowsThese volcanologicaldifferences are primarily related to the eruption environ-ment (deep-water shallow-water or subaerial) The rapidgrowth of the plateau prevented significant accumulationsof intervening sediment except in the uppermost stratigra-phy where isolated limestone lenses commonly associatedwith pillow basalt and hyaloclastite deposits preserve arecord of the final stages of subsidence of the plateauThe Wrangellia plateau on Vancouver Island was con-

structed dominantly of tholeiitic basalt with restrictedmajor- and trace-element and isotopic compositional var-iations Minor volumes of picritic pillow basalts eruptedlate in the submarine phase The Karmutsen basalts wereemplaced onto older Paleozoic arc volcanic sequences andlow NbLa for the picrites may indicate a contributionfrom the sub-arc lithospheric mantle Modeling of the pet-rogenesis of the Karmutsen picrites indicates melting ofanomalously hot mantle (15008C) and extensive degreesof partial melting (23^27) and is consistent with aplume initiation model Combined Sr^Nd^Hf^Pb isotopicsystematics indicate that the picritic and tholeiitic lavaswere derived from a depleted plume-type mantle sourcedistinct from the source of MORB that has compositionalsimilarities to the source of the lavas forming theCaribbean Plateau Picrites were generated by melting ofspinel lherzolite whereas the tholeiitic basalts formed asaggregate melts of both garnet and spinel lherzolite Thetholeiitic basalts underwent extensive low-pressure fractio-nation (52^3 kbar) and seismic studies indicate that someof theWrangellia crust beneathVancouver Island may cor-respond to the plutonic residues of the Karmutsen floodbasalts

ACKNOWLEDGEMENTSWe are grateful to Nick Arndt for helping us get this pro-ject started and Nick Massey for insights into VancouverIsland geology We greatly appreciate the assistance withPRIMELT modeling from Claude Herzberg We thankMikkel Schau for his insight and enthusiasm during field-work Jane Barling assisted with analyses by MC-ICP-MSThoughtful and thorough reviews of the manuscript byJohn Mahoney Fred Frey Wendy Bohrson DougalJerram and Teal Riley are greatly appreciated Fundingwas generously provided by the Rocks to Riches Programadministered by the BC amp Yukon Chamber of Mines in2004 by the BC Geological Survey and by NSERCDiscovery Grants to JSS and DW ARG was supportedby a University Graduate Fellowship at UBC

SUPPLEMENTARY DATASupplementary data for this paper are available at Journalof Petrology online


34

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Cosmochimica Acta 65(1) 153^162

APPENDIX SAMPLEPREPARAT ION ANDANALYT ICAL METHODSOnly the freshest rocks in the field were sampled and onlythe least altered samples were selected for chemical andisotopic analysis based on thorough petrographic inspec-tion Fifty-nine of the 129 collected samples were crushed(400 g) into small pieces 52mm in diameter in aRocklabs hydraulic piston crusher between WC plates tominimize contamination The coarse-crush was mixedand 100 g was powdered in a planetary mill using agatejars and balls cleaned with quartz sand between samples

ActLabs analytical methodsThe major- and trace-element compositions of the whole-rock powders were determined at Activation LaboratoriesLtd (Actlabs) in Ancaster Ontario Analytical techniquesand detection limits are also available from Actlabs (httpwwwactlabscommethsub_code4erehtm) The analyticalmethod for each of the elements analyzed is indicated inTable 2 For the major elements a 02 g sample was mixedwith a lithium metaborate^lithium tetraborate mixtureand fused in a graphite crucible The molten mixture waspoured into a 5 HNO3 solution and shaken until dis-solved (30min) The samples were analyzed for majoroxides and selected trace elements by inductively coupledplasma optical emission spectrometry (ICP-OES) on acombination simultaneous^sequential Thermo Jarrell-AshEnviro II system Internal calibration was achieved usinga variety of international reference materials (eg W-2BIR-1 DNC-1) and independent control samplesAdditional trace elements were analyzed by both instru-mental neutron activation analysis (INAA) and induc-tively couple plasma mass spectrometry (ICP-MS) ForINAA15^25 g of sample was weighed into small polyeth-ylene vials and irradiated with a control international ref-erence material CANMET WMS-1 and NiCr flux wires ata thermal neutron flux of 71012 neutronscm2 per s in theMcMaster Nuclear Reactor Following a 7 day waitingperiod the samples were measured on an Ortec high-purity Ge detector linked to a Canberra Series 95 multi-channel analyzer Activities for each element weredecay- and weight-corrected and compared with a detectorcalibration developed from multiple international certifiedreference materials For ICP-MS 025 g of sample wasdigested in HF followed by HNO3^HClO4 heated andtaken to dryness The samples were brought back into solu-tion with HCl Samples were analyzed using a PerkinElmer Optima 3000 ICP In-lab standards or certified ref-erence materials (eg W-2 BIR-1 DNC-1) were used for

quality control A total of 15 blind duplicates were ana-lyzed from the same sample powders to assessreproducibility

University of Massachusetts analyticalmethodsFourteen sample duplicate powders taken from the same100 g sample aliquot (high-MgO basalts and picrites)were also analyzed at the Ronald B Gilmore X-RayFluorescence (XRF) Laboratory at the University ofMassachusetts Major elements were measured on a fusedLa-bearing lithium borate glass disc using a SiemensMRS-400 spectrometer Trace element concentrations(Rb Sr Ba Ce Nb Zr Y Pb Zn Ga Ni Cr V) weremeasured on a separate powder pellet using a PhilipsPW2400 sequential spectrometer using a Rh tube LOIand ferrous iron measurements were made as describedby Rhodes amp Vollinger (2004) Precision and accuracy esti-mates for the data have been described by Rhodes (1996)and Rhodes amp Vollinger (2004) Results for each sampleare the average of two separate analyses and are shown inElectronic Appendix 2 for a comparison of analyses ofduplicate powders using XRFand ICP-MS

PCIGR analytical methodsA subset of 19 samples was selected for high-precisiontrace-element analysis and Sr Nd Pb and Hf isotopicanalysis at the Pacific Centre for Isotopic andGeochemical Research (PCIGR) at the University ofBritish Columbia (UBC) Samples were selected from the59 samples analyzed for whole-rock chemistry at ActLabsbased on major- and trace-element chemistry alteration(low LOI and petrographic alteration index) and samplelocation Samples were prepared for trace-element analysisat the PCIGR by the technique described by Pretorius et al(2006) on unleached rock powders Sample powders(100mg) were weighed in 7ml screw-top Savillex bea-kers and dissolved in 1ml 14N HNO3 and 5ml 48 HFon a hotplate for 48 h at 1308C with periodic ultrasonica-tion Samples were dried and redissolved in 6ml 6N HClon a hotplate for 24 h and then dried and redissolved in1ml concentrated HNO3 for 24 h before final dryingTrace element abundances were measured by high-resolution inductively coupled plasma-mass spectrometry(HR-ICP-MS) with aThermo Finnigan Element2 systemfollowing the procedures described by Pretorius et al(2006) within 24 h of redissolution HFSE and LILE weremeasured in medium-resolution mode at 2000 dilutionusing a PFATeflon spray chamber washed with aqua regiafor 3min between samples REE were measured in high-resolution mode and U and Pb in low-resolution modeat 2000 dilution using a glass spray chamber washedwith 2 HNO3 between samples Total procedural blanksand reference materials (BCR-2 BHVO-2) were analyzedwith the batch of samples Indium was used as an internal


38

standard in all samples and standard solutionsBackground and standard solutions were analyzed afterevery five samples to detect memory effects and massdrift Results for PCIGR trace-element analyses areshown in Electronic Appendix 3 for the full set of analyzedtrace elementsSample digestion for purification of Sr Nd Hf and Pb

for column chemistry began by weighing each samplepowder (400^500mg) prior to leaching All samples wereleached with 6N HCl and placed in an ultrasonic bath for15min Samples were rinsed twice with 18 M-cm H2Obetween each leaching step (15 total) until the supernatantliquid was clear [following the method of Mahoney (1987)]Samples were then dried on a hotplate for 24 h andweighed again Sample solutions were then prepared bydissolving 100^250mg of the leached powder dissolvedin 1ml 14N HNO3 and 10ml 48 HF on a hotplate for48 h at 1308C with periodic ultrasonication Samples weredried and redissolved in 6ml 6N HCl on a hotplate for24 h and then dried Pb was separated using anion exhangecolumns and the discard was used for Sr REE and Hfseparation Nd was separated from the other REE and Hfrequired two additional purification steps Detailed proce-dures for column chemistry for separating Sr Nd and Pbat the PCIGR have been described byWeis et al (2006) andHf purification has been described byWeis et al (2007) Srand Nd isotope ratios were measured by thermal ioniza-tion mass spectrometry (TIMS) on a Thermo FinniganTriton system in static mode with relay matrix rotation ona single Ta and double Re^Ta filament respectively Fourto five filaments per barrel of 21 were occupied by stan-dards (NBS 987 for Sr and LaJolla for Nd) for each barrelwhere samples were run Sample Sr and Nd isotopic com-positions were corrected for mass fractionation using86Sr88Srfrac14 01194 and 146Nd144Ndfrac14 07219 Each samplewas then normalized using the barrel average of the refer-ence material relative to the values of143Nd144Ndfrac14 0511858 and 87Sr86Srfrac14 0710248 (Weiset al 2006) During the course of the Vancouver Islandanalyses the La Jolla Nd standard gave an average valueof 05118566 (nfrac14 7) and NBS987 standard gave an aver-age of 07102408 (nfrac1411) (2 error is reported as times106) 147Sm144Nd errors are 15 or 0006 USGeological Survey (USGS) reference material BHVO-2was processed with the samples and yielded Sr and Nd iso-topic ratios of 07034607 and 05129786 respectivelyThese are in agreement with the published values of070347920 and 051298411 respectively (Weis et al2006)

Pb and Hf isotopic compositions were analyzed by mul-tiple collector-inductively coupled plasma-mass spectrome-try (MC-ICP-MS) on a static multi-collection on a NuPlasma (Nu Instruments) system The detailed analyticalprocedure for Pb isotopic analyses on the Nu Plasma atthe PCIGR has been described by Weis et al (2006) Theconfiguration for Pb analyses allows for collection of PbTl and Hg togetherTl and Hg are used to monitor instru-mental mass discrimination and isobaric overlap repec-tively All sample solutions were analyzed withapproximately the same PbTl ratio (4) as the referencematerial NIST SRM 981 To accomplish this a small ali-quot of each sample solution from the Pb columns was ana-lyzed on the Element2 to determine the precise amount ofPb available for analysis on the Nu Plasma The SRM 981standard was run after every two samples on the NuPlasma During the time samples were run analyses ofthe SRM 981 Pb reference material gave values of206Pb204Pbfrac1416940322 207Pb204Pbfrac1415495823and 208Pb204Pbfrac14 36713164 (nfrac14 61 2 error is reportedas times 104) these values are in excellent agreement withreported TIMS triple-spike values of Galer amp Abouchami(1998) Fractionation-corrected Pb isotopic ratios were fur-ther corrected by the sample-standard bracketing methodor the ln^ln correction method described by White et al(2000) and Blichert-Toft et al (2003) Leached powders ofUSGS reference material BHVO-2 yielded Pb isotopicratios of 206Pb204Pbfrac14186454 8 207Pb204Pbfrac14 1549105 and 208Pb204Pbfrac14 38222514 and BCR-2yielded 206Pb204Pbfrac141880466 207Pb204Pbfrac14 1562518 and 208Pb204Pbfrac14 3883496 (2 error isreported as times 104) These values are in agreement withthose for leached residues of BHVO-2 and BCR-2 fromWeis et al (2006)Hf isotopic compositions were analyzed following the

procedures detailed byWeis et al (2007) The configurationfor Hf analyses monitored Lu mass 175 andYb mass 172 toallow for interference correction to masses 174 and 176 Hfisotopic ratios were normalized internally for mass fractio-nation to a 179Hf177Hf ratio of 07325 using an exponentialcorrection Standards were run after every two samplesand sample results were normalized to the ratio of the in-run daily average and a 176Hf177Hf ratio for JMC-475 of0282160 During the course of analyses the Hf standardJMC-475 gave an average value 02821679 (nfrac14130)USGS reference materials BCR-2 and BHVO-2 were pro-cessed with the samples and yielded Hf isotopic ratios of02828675 and 02831005 respectively Publishedvalues for BCR-2 and BHVO-2 are 02828717 and0283104 8 respectively (Weis et al 2007)


39

result of unusually high melt production rates are predo-minantly basaltic in composition and their formation isnot directly attributable to seafloor spreading processes(eg Saunders 2005) The high melt production rates arebest explained by high mantle source temperatures in rap-idly upwelling mantle (ie mantle plumes) direct evidenceof high mantle temperatures is the eruption of primitivehigh-MgO lavas (Kerr amp Mahoney 2007) Studies of oce-anic plateaus can be used to constrain aspects of mantleplume-related magmatism including the composition ofthe mantle source involved the temperature and depth ofmelting the volume of magma and melt production ratesand the mechanisms of emplacement of voluminous lavasequences From a geochemical perspective the study ofoceanic plateaus is important because the chemistry of thelavas has generally been unaffected by continental crustalcontaminationAt present one of the great challenges in studying oce-

anic plateaus in the ocean basins is the difficulty in drillingto depths of more than a few hundred meters into thebasaltic basement rocks (eg Kerguelen Ontong Java)Accreted sections of oceanic plateaus (eg CaribbeanOntong Java) provide an opportunity to closely examinetheir volcanic stratigraphyWrangellia flood basalts in thePacific Northwest of North America are part of a majorlarge igneous province that erupted in a marine setting inthe Late Triassic (c 225^231 Ma) and accreted to westernNorth America in the Late Jurassic or Early Cretaceous(Richards et al 1991) Although their original areal distri-bution was probably considerably larger much of the orig-inal stratigraphic thickness (6 km on Vancouver Island35 km in Alaska) is intact Current exposures of theflood basalts are preserved in a narrow belt over 2300 kmin length resulting from transform fault motions afteraccretion which extends from southern British Columbiathrough the Yukon and into Alaska Richards et al (1991)proposed a plume initiation model for the Wrangelliaflood basalts based on the short duration and estimatedhigh eruption rate of the volcanism evidence of upliftprior to volcanism and lack of evidence of associated rift-ing (ie few dikes and abundant sills)TheWrangellia flood basalts are perhaps the most exten-

sive accreted remnants of an oceanic plateau in the worldwhere parts of the entire volcanic stratigraphy areexposed however they have been the focus of few inte-grated field geochemical and radiogenic isotopic studiesThe internal architecture of oceanic plateaus can provideconstraints on the sequence of melting events associatedwith mantle plumes that occur beneath the oceans in ananalogous way to the use of continental flood basalts toelucidate the sequential development of mantle plumesand rifting within continental lithosphere (eg Peate 1997Storey et al 1997) The internal stratigraphy of continentalflood basalts is far more complex than previously realized

(eg Jerram amp Widdowson 2005) and because of theirrelative inaccessibility the structure of flood basaltsequences in oceanic plateaus is not well known In thisstudy we examine the field relationships petrographymajor and trace elements and Sr^Nd^Hf^Pb isotopiccompositions of Wrangellia flood basalts from variousareas of Vancouver Island to assess the nature of themantle source conditions of melting and magmatic his-tory of the basalts in the context of the construction ofthis major oceanic plateau This study is part of a compre-hensive research project on the nature origin and evolu-tion of the Triassic Wrangellia flood basalt province inBritish Columbia Yukon and Alaska (Greene et al 20082009)

GEOLOGICAL SETT INGWrangellia on Vancouver IslandWrangellia flood basalts form the core of the Wrangelliaterrane orWrangellia one of the largest outboard terranesaccreted to western North America (Jones et al 1977)Middle to LateTriassic flood basalts extend in a discontin-uous belt from Vancouver and Queen Charlotte Islands(Karmutsen Formation) through SE Alaska and SWYukon and into the Wrangell Mountains Alaska Rangeand Talkeetna Mountains in east and central Alaska(Nikolai Formation Fig 1)Wrangellia covers 80 of Vancouver Island which is

460 km long by 130 km wide (Fig 1) Wrangellia is theuppermost sheet of a stack of SW-vergent thrust sheetsthat form the crust of Vancouver Island and has a cumula-tive thickness of410 km (Monger amp Journeay 1994) Pre-Karmutsen units of Wrangellia on Vancouver Islandinclude Devonian arc sequences of the Sicker Group andMississippian to Early Permian siliciclastic and carbonaterocks of the Buttle Lake Group (Muller 1980 Sutherland-Brown et al1986)These Paleozoic sequences have variableestimated thicknesses (2^5 km Muller 1980 Massey1995a) and are exposed only on central and southernVancouver Island (Fig 1) The Karmutsen Formation isoverlain by the shallow-water Quatsino limestone (30^750m) and shallow- to deeper-water Parson BayFormation (600m) which is intercalated with and over-lain by Bonanza arc volcanics (169^202 Ma Nixon et al2006b) Bonanza arc plutonic rocks (167^197 Ma) alsointrude the Karmutsen Formation and are some of theyoungest units of Wrangellia that formed prior to accretionwith North America (Nixon et al 2006b) Following accre-tionWrangellia units were intruded by the predominantlyCretaceous Coast Plutonic Complex (Wheeler amp McFeely1991)The Karmutsen Formation (19142 km2 calculation

based on digital geological compilations) is composed ofbasal sediment^sill complexes a lower unit of pillowed


2






3









4



5



6






7


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39






3









4



5



6






7


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39









4



5



6






7


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39



5



6






7


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39



6






7


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39






7


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39


BC















































(continued)


8





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39





Table 1 Continued















9

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

00

05

10

15

20

25

30

35

40

0 5 10 15 20 25

10

11

12

13

14

15

16

17

18

19

20

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

0 5 10 15 20 25

6

7

8

9

10

11

12

13

14

15

16

0 5 10 15 20 25

0

1

2

3

4

5

6

40 45 50 55 60

0

200

400

600

800

0 5 10 15 20 25

(wt)(wt)

(wt)

(wt)

+K2ONa2O TiO2

FeO (T)

Ni (ppm)

Al2O3

CaO

alkalic

tholeiitic

Karmutsen Form



(compiled data)


SiO2 (wt) MgO (wt)

MgO (wt)MgO (wt)

MgO (wt) MgO (wt)

(a) (b)

(g)

(e)

(f)

(c)

LOI (wt )

(d)

MgO (wt )0

1

2

3

4

5

6

7

0 5 10 15 20 25

(wt)



10


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39


Vancouver Island BC





UTM EW 5455062 5455150 5455150 5455459 5455518 5455280 5454625 5454625 5567712 5567305

UTM NS 384113 384260 384260 383424 383237 382261 381761 381761 708686 707890


SiO2 4793 4865 4907 4841 4869 4844 4968 4908 4924 4847

TiO2 165 186 184 140 136 149 171 168 158 172

Al2O3 1441 1430 1415 1589 1592 1474 1493 1406 1354 1352

Fe2O3 1229 1207 1248 990 1074 1213 975 1221 1130 1161

MnO 017 018 018 016 016 017 019 018 021 019

MgO 625 621 616 681 674 689 698 655 609 712

CaO 1022 1185 1170 1131 1076 1156 1096 1094 1400 1194

Na2O 322 228 225 251 289 239 223 224 212 218

K2O 024 018 014 035 034 024 027 031 010 029

P2O5 015 014 015 010 012 012 008 013 012 012

LOI 272 138 122 217 228 164 197 163 115 195

Total 9924 9909 9933 9901 9998 9981 9875 9900 9945 9911


La 788 903 872 650 658 610 717 702 720 788

Ce 190 222 216 155 162 154 180 177 173 190

Pr 271 310 302 215 220 223 262 252 242 272

Nd 130 152 145 107 112 114 132 125 122 135

Sm 357 411 405 303 313 342 367 366 343 385

Eu 140 157 148 118 120 125 147 139 133 147

Gd 439 477 487 359 364 390 432 424 412 448

Tb 076 082 082 063 064 068 076 074 071 078

Dy 455 502 479 380 387 412 468 441 428 478

Ho 090 099 096 077 078 084 094 089 087 095

Er 257 279 272 220 227 234 266 245 248 269

Tm 036 040 039 032 032 033 037 035 034 038

Yb 215 239 232 190 196 200 223 211 205 233

Lu 031 033 032 027 027 028 030 030 029 033

Sc 407 413 404 389 383 402 428 428 411 462

V 328 351 353 285 279 317 341 341 325 344

Cr 93 146 125 290 297 252 130 131 151 168

Co 487 499 489 461 454 514 531 534 505 562

Ni 87 90 88 125 122 115 94 103 83 93

Cu 177 201 198 167 158 159 180 168 167 184

Zn 83 91 91 77 73 82 86 87 79 88

Ga 19 19 20 17 19 18 16 18 19 17

Ge 16 15 14 11 15 15 07 15 19 11

Rb 4 2 2 6 6 4 5 5 6

Sr 418 231 228 282 332 263 281 286 192 214

Y 25 28 28 22 22 24 26 26 25 27

Zr 86 97 94 72 71 77 86 83 83 90

Nb 84 101 100 70 68 65 74 73 79 86

Cs 07 03 02 05 05 02 02 02 02

Ba 173 50 49 71 98 62 143 133 28 81

Hf 26 28 28 20 22 21 26 25 24 26

Ta 059 068 065 045 046 041 053 049 051 060

Pb 4 7 7 10 4 6 7 11 7 9

Th 065 074 072 052 053 054 061 061 057 064

U 020 023 024 017 016 017 022 019 018 020

(continued)


11

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

Table 2 Continued





UTM EW 5566984 5563304 5566800 5564002 5563843 5563936 5564229 5564285 5564343 5590769

UTM NS 707626 705978 700781 703739 704932 704941 704928 704896 705008 634318


SiO2 4916 4888 4802 4806 4817 4956 4817 4949 4937 4833

TiO2 178 178 177 177 189 177 177 179 181 180

Al2O3 1400 1384 1434 1411 1496 1392 1416 1398 1398 1359

Fe2O3 1330 1346 1318 1373 1140 1307 1324 1313 1353 1375

MnO 019 018 020 019 018 017 018 018 020 019

MgO 639 612 673 635 639 606 661 646 598 697

CaO 1185 1143 1137 1161 1175 1215 1130 1176 1159 1142

Na2O 186 216 197 208 193 201 203 192 192 203

K2O 014 014 011 011 010 009 015 012 015 014

P2O5 015 016 015 016 013 016 014 014 015 015

LOI 093 142 191 137 211 076 178 087 104 148

Total 9975 9956 9973 9952 9901 9973 9953 9985 9971 9984


La 844 807 686 706 731 786 742 721 762 695

Ce 205 195 175 173 189 192 183 179 188 178

Pr 288 273 254 246 278 270 266 257 273 253

Nd 143 135 126 123 135 135 133 130 139 129

Sm 407 387 372 351 406 384 384 381 391 372

Eu 149 145 137 136 147 146 140 138 147 141

Gd 470 474 440 419 472 447 459 428 473 442

Tb 081 083 077 075 081 079 079 077 083 077

Dy 490 492 486 462 499 475 488 477 512 461

Ho 099 098 098 093 103 096 098 097 104 094

Er 281 279 278 265 296 272 282 280 299 265

Tm 039 040 040 037 041 038 039 040 042 038

Yb 231 246 251 227 250 235 242 240 255 232

Lu 033 035 035 033 036 032 035 034 035 032

Sc 429 445 420 440 444 421 423 422 397 392

V 349 362 362 362 378 351 364 364 367 365

Cr 122 156 155 166 158 118 164 151 122 143

Co 537 548 545 555 548 516 549 533 465 500

Ni 92 105 116 112 106 91 115 108 90 107

Cu 202 185 218 187 208 195 206 211 210 189

Zn 92 93 109 90 86 90 87 92 92 104

Ga 20 19 19 18 18 19 19 19 19 19

Ge 16 16 18 14 13 17 13 17 16 14

Rb 2 1 1 2 1 1 1 1 2

Sr 179 188 174 196 174 187 162 160 171 190

Y 27 28 28 28 30 26 28 29 29 27

Zr 97 92 95 88 97 97 95 95 96 96

Nb 91 82 83 78 85 90 85 86 85 83

Cs 02 01 02 01 06 02 04 03 02 02

Ba 34 38 33 35 36 39 34 28 34 34

Hf 27 26 27 26 29 28 28 27 29 28

Ta 060 056 055 053 058 060 057 055 059 055

Pb 7 8 8 8 14 8 9 9 5 11

Th 068 061 062 061 068 069 062 062 067 066

U 020 019 019 018 022 021 020 019 020 019

(continued)


12

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

Table 2 Continued





UTM EW 5590769 5590769 5590769 5578863 5580653 5595261 5593546 5588018 5599424 5595513

UTM NS 634318 634318 634318 630940 704736 615253 615098 618867 620187 629434


SiO2 4867 4723 4816 5003 4808 4669 4806 4778 4761 4831

TiO2 182 178 178 208 173 176 174 186 187 175

Al2O3 1374 1377 1362 1231 1639 1332 1335 1291 1355 1345

Fe2O3 1305 1413 1376 1521 1113 1272 1296 1423 1434 1348

MnO 019 019 019 022 020 017 019 021 019 020

MgO 702 709 709 566 554 709 638 647 742 678

CaO 1142 1143 1148 919 1238 1062 1051 1024 986 1177

Na2O 205 202 208 294 201 349 323 291 287 180

K2O 013 006 014 070 010 001 044 044 021 003

P2O5 014 014 012 018 015 014 013 015 015 014

LOI 134 138 137 155 129 353 239 202 192 174

Total 9956 9922 9979 10007 9901 9943 9937 9921 100 9943

Trace eements (ppm)

La 734 765 695 893 798 804 723 851 817 732

Ce 185 193 178 215 194 197 180 209 202 184

Pr 264 294 267 310 272 296 268 308 301 269

Nd 127 136 133 155 133 137 123 147 143 129

Sm 366 405 377 420 369 388 36 42 412 378

Eu 142 155 142 162 142 144 139 159 158 147

Gd 462 476 459 521 458 447 424 479 488 44

Tb 077 083 080 090 075 079 077 087 085 079

Dy 460 492 477 540 453 459 457 512 501 465

Ho 094 092 095 111 089 085 089 098 094 089

Er 270 264 269 323 254 247 253 283 27 258

Tm 038 0389 037 045 036 037 036 0413 0404 0379

Yb 227 241 228 271 226 227 226 254 251 234

Lu 034 0349 034 039 032 0325 0329 0375 0365 0339

Sc 292 416 415 383 344 438 438 424 445 404

V 365 362 362 496 299 354 362 372 380 353

Cr 98 162 165 342 207 195 76 719 172 173

Co 377 557 535 471 431 489 536 515 574 53

Ni 105 93 93 61 98 93 67 65 86 96

Cu 189 178 174 306 198 134 181 165 182 175

Zn 103 98 94 107 76 80 93 102 84 88

Ga 19 20 17 20 21 20 17 20 19 20

Ge 15 15 12 16 15 14 09 16 13 14

Rb 2 2 2 12 9 8 5 2

Sr 193 178 190 299 272 86 381 274 287 194

Y 28 26 27 32 25 26 27 29 29 28

Zr 87 94 102 110 92 90 86 98 98 91

Nb 84 85 85 97 86 81 80 90 86 80

Cs 02 04 02 04 01 08 04 01 09 06

Ba 34 28 33 152 32 11 80 85 39 39

Hf 26 28 28 31 27 27 25 29 30 27

Ta 054 06 057 065 060 06 05 07 06 06

Pb 12 91 5 97 97 98 97 91

Th 064 059 068 077 069 075 062 066 064 059

U 020 023 015 027 025 03 024 026 027 022

(continued)


13

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

Table 2 Continued





UTM EW 5595376 5585731 5557892 5552258 5552258 5566161 5566422 5566422 5560585 5581870

UTM NS 629069 623077 338923 341690 341690 704411 703056 703056 702230 704472


SiO2 4729 4672 4861 4790 4029 4890 4960 4953 4738 4908

TiO2 181 194 175 136 216 180 181 181 083 146

Al2O3 1370 1321 1282 1379 1627 1421 1434 1436 1442 1477

Fe2O3 1423 1411 1381 1162 1810 1178 1337 1339 1058 1160

MnO 020 024 021 016 028 020 020 020 016 013

MgO 677 629 696 657 970 640 593 594 769 873

CaO 1065 1119 1054 1208 678 1208 1169 1168 1166 1102

Na2O 258 249 276 313 058 182 197 197 277 199

K2O 021 001 050 012 052 031 015 013 012 015

P2O5 014 016 014 010 018 012 016 015 006 012

LOI 157 338 180 317 477 138 075 075 407 098

Total 9914 9966 999 9999 9963 9900 9997 9990 9975 10002


La 734 887 772 657 107 775 784 774 224 557

Ce 185 210 191 154 243 190 190 193 56 143

Pr 284 302 285 222 348 271 267 274 085 209

Nd 132 144 135 105 159 139 133 137 48 104

Sm 392 416 398 298 453 403 386 389 176 298

Eu 148 159 147 121 204 143 142 143 075 121

Gd 465 481 456 356 564 462 473 466 258 385

Tb 081 086 079 063 099 081 081 082 050 065

Dy 479 507 471 384 595 501 495 497 338 401

Ho 091 092 088 075 115 101 101 101 076 081

Er 258 272 256 216 336 289 292 289 231 227

Tm 038 0413 0375 0331 0495 041 042 040 034 033

Yb 242 262 235 212 311 251 249 244 216 198

Lu 0348 0378 0342 0296 0455 036 034 035 031 028

Sc 398 416 429 418 542 434 442 499 351

V 363 401 367 313 499 363 366 367 288 287

Cr 166 76 114 194 159 152 154 311 352

Co 524 508 53 46 62 525 526 495 524

Ni 94 58 79 67 68 107 97 85 121 209

Cu 185 210 25 125 109 188 212 210 134 208

Zn 86 85 89 92 75 96 93 94 64 83

Ga 20 22 19 18 24 18 19 19 14 19

Ge 13 16 15 15 13 12 16 17 14 16

Rb 9 8 3 10 10 2 2 2 2

Sr 279 67 227 170 220 155 173 174 130 167

Y 28 30 27 21 38 27 29 28 21 23

Zr 96 100 89 67 112 94 94 93 38 73

Nb 85 92 81 66 98 87 86 87 17 65

Cs 13 04 06 09 03 03 03 03

Ba 61 8 103 17 109 39 45 43 68 55

Hf 28 29 27 2 33 27 27 28 12 21

Ta 06 06 06 05 07 057 056 055 009 042

Pb 92 96 83 66 65 7 14 6 7

Th 061 063 057 045 071 064 061 061 024 043

U 024 025 022 022 034 021 019 019 011 016

(continued)


14

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

Table 2 Continued





UTM EW 5588246 5589935 5601095 5601095 5584647 5560375 5557712 5557712 5595528 5595528

UTM NS 618183 615917 624103 624103 623236 702240 700905 700905 629490 629490


SiO2 4617 4620 4776 4653 4677 4910 4931 4740 4385 4384

TiO2 177 161 213 212 181 090 171 171 043 043

Al2O3 1380 1477 1441 1406 1423 1372 1339 1333 1156 1174

Fe2O3 1353 1089 1250 1301 1285 1134 1239 1271 1011 965

MnO 014 012 019 018 019 016 017 017 016 016

MgO 825 937 571 570 728 699 750 746 1774 1751

CaO 1041 1022 881 1000 1092 1096 1201 1193 943 936

Na2O 201 155 416 364 186 346 183 180 053 053

K2O 021 008 020 009 016 003 022 017 010 013

P2O5 014 013 018 019 013 008 013 014 004 000

LOI 287 407 317 345 292 323 128 138 545 533

Total 993 9903 992 9896 9914 9997 9995 9821 9939 9866


La 731 688 116 117 714 284 813 794 106 096

Ce 187 176 284 269 179 69 197 192 26 25

Pr 281 268 401 395 272 11 289 285 041 038

Nd 132 125 177 177 129 61 133 133 26 23

Sm 389 343 474 476 382 214 383 377 092 084

Eu 147 134 178 173 147 0888 145 143 038 037

Gd 461 403 549 532 449 305 436 432 140 142

Tb 081 07 093 093 079 063 075 075 030 030

Dy 476 411 549 531 466 419 435 425 216 217

Ho 09 076 102 098 09 086 083 081 049 050

Er 255 218 291 286 26 265 237 231 153 154

Tm 0375 0324 0441 043 0373 0415 0341 0342 024 023

Yb 235 2 275 273 235 266 213 214 158 152

Lu 0336 029 0392 0391 034 0401 0304 0298 023 023

Sc 393 323 357 385 40 545 408 377 383 401

V 332 271 381 376 349 327 342 338 201 189

Cr 328 400 127 164 317 210 274 255 1710 1830

Co 589 568 394 437 526 468 518 476 803 846

Ni 147 213 73 85 110 70 98 97 755 755

Cu 83 111 105 148 164 160 161 160 92 83

Zn 86 72 86 102 87 69 77 76 77 55

Ga 20 19 21 21 20 16 19 19 10 9

Ge 13 11 14 14 13 13 11 07 10 07

Rb 3 2 3 7 7 5 4

Sr 283 183 128 170 237 58 255 254 100 97

Y 28 23 32 31 25 27 24 23 16 13

Zr 91 86 116 121 91 45 89 86 16 19

Nb 82 77 127 130 81 21 89 85 07 09

Cs 01 02 02 12 02 02 02 28 27

Ba 62 32 36 34 39 12 38 37 19 18

Hf 28 26 34 35 27 14 26 25 05 06

Ta 05 05 09 09 06 01 06 06 009 003

Pb 94 82 110 118 93 48 85 83 7 4

Th 054 052 092 093 052 028 061 057 010 011

U 021 022 034 033 023 016 023 025 005 003

(continued)


15

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

Table 2 Continued





UTM EW 5595528 5588274 5586081 5599233 5599233 5599183 5595569 5586126 5598448 5599395

UTM NS 629490 626641 626835 616507 616507 616472 629573 626824 616507 616613


SiO2 4294 4441 4439 4462 4471 4624 4408 4535 4370 4793

TiO2 042 054 066 044 044 047 045 064 044 046

Al2O3 1126 1275 1493 1371 1375 1457 1168 1407 1366 1402

Fe2O3 1082 1033 1011 1038 1037 857 1098 1040 1047 993

MnO 016 015 014 014 014 015 018 014 016 019

MgO 1828 1542 1302 1447 1448 1211 1794 1256 1555 1584

CaO 898 873 973 937 936 1081 919 900 871 1042

Na2O 054 078 156 086 086 130 037 211 098 102

K2O 002 007 007 006 007 001 011 002 004 011

P2O5 003 005 006 005 005 004 004 006 004 008

LOI 570 561 491 559 559 491 498 468 605

Total 9916 9883 9958 9968 9981 9914 10000 9902 998 10000


La 108 180 178 140 136 179 102 173 152 14

Ce 26 45 45 34 34 43 26 47 36 36

Pr 043 067 071 052 051 065 041 077 055 056

Nd 25 38 41 30 29 34 24 44 30 29

Sm 087 127 148 100 101 111 085 147 102 123

Eu 0405 051 063 046 044 0501 0361 0607 0454 047

Gd 145 186 216 171 169 174 135 213 157 210

Tb 03 037 042 036 035 037 03 042 034 032

Dy 211 260 279 254 250 267 212 278 244 238

Ho 047 059 060 059 056 06 046 059 055 064

Er 154 186 179 189 179 187 146 178 173 211

Tm 0242 029 026 029 028 0297 0236 0267 0268 0297

Yb 162 185 167 189 184 201 158 175 177 197

Lu 0244 028 025 029 028 0308 0245 0269 0277 0282

Sc 364 410 381 435 45 395 383 375

V 194 218 235 219 222 222 222 215 204 140

Cr 1750 1570 725 1370 1370 1850 906 3000 606

Co 80 729 604 722 687 893 672 679

Ni 755 656 339 583 583 564 680 368 559 491

Cu 83 110 106 142 98 104 80 83 77 91

Zn 55 60 63 106 62 53 54 50 53 57

Ga 11 12 13 12 12 11 10 14 12

Ge 12 11 11 12 13 09 09 11 11

Rb 6 2 2 2 1 6 2

Sr 93 64 132 73 73 120 120 189 112

Y 15 17 18 16 17 18 15 16 16 13

Zr 16 29 36 24 22 22 15 35 22 24

Nb 07 13 11 08 07 07 07 14 09 09

Cs 58 09 08 07 07 04 45 06 08

Ba 27 15 20 13 13 18 24 15 20 20

Hf 06 09 10 07 07 07 05 11 07 08

Ta 006 005 004 004 01

Pb 22 4 8 26 22 34 22

Th 009 020 010 015 014 015 008 009 014 015

U 007 009 005 008 007 011 007 007 01

(continued)


16

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

Table 2 Continued

Sample 4723A21 5614A31 5614A51 5616A7 4722A5(1)1 4722A5(2)1 5615A11 5617A4




UTM EW 5588266 5599183 5599192 5589833 5595029 5595029 5595029 5557712

UTM NS 626698 616472 614756 626879 627605 627605 627605 700905


SiO2 4673 4843 4710 4675 4895 4845 4908 4806

TiO2 061 048 051 073 230 233 230 351

Al2O3 1524 1490 1452 1592 1361 1251 1186 1279

Fe2O3 1026 759 912 1088 1256 1524 1520 1678

MnO 016 013 014 015 019 019 022 016

MgO 1027 1066 1092 870 618 599 573 525

CaO 993 1068 1078 1169 933 899 984 648

Na2O 226 151 210 212 326 330 325 231

K2O 038 006 001 007 030 030 004 069

P2O5 006 004 005 004 013 019 022 035

LOI 370 413 467 286 200 195 207 322

Total 9960 986 9989 9991 9880 9945 9981 996


La 194 171 091 151 877 946 641 223

Ce 50 40 25 38 230 252 173 515

Pr 074 059 043 059 337 368 289 719

Nd 42 32 27 35 172 179 156 327

Sm 141 109 102 136 520 521 506 886

Eu 052 0483 0526 0638 174 179 188 333

Gd 209 171 16 205 639 663 619 984

Tb 042 037 034 043 111 120 113 164

Dy 291 266 235 29 659 708 665 958

Ho 067 059 052 061 134 139 124 178

Er 210 187 167 191 385 394 367 506

Tm 032 0292 027 0305 055 057 0547 073

Yb 206 199 18 202 331 348 344 456

Lu 031 0312 0267 0302 045 051 0493 0637

Sc 472 488 437 507 387 331 438 442

V 261 217 206 270 481 495 520 517

Cr 358 1420 797 346 797 590 107 644

Co 488 761 686 567 456 407 534 383

Ni 163 551 315 122 59 59 56 39

Cu 111 111 96 111 116 114 208 232

Zn 61 51 48 51 106 103 94 160

Ga 13 12 13 15 17 20 18 27

Ge 12 08 09 1 07 13 07 2

Rb 10 6 6 21

Sr 271 130 141 181 225 229 143 197

Y 20 17 16 19 39 39 39 52

Zr 33 24 19 26 127 126 124 229

Nb 15 08 05 11 100 106 99 197

Cs 65 04 03 03 04 01 12

Ba 84 20 9 23 87 88 20 771

Hf 10 07 06 08 37 37 38 64

Ta 008 067 070 07 14

Pb 28 29 37 6 7 113 151

Th 023 017 008 014 108 108 101 209

U 010 011 006 009 038 039 041 088




17






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39






Mount Arrowsmith

Karmutsen RangeS

ampl

eC

hond

rite

Sam

ple

Cho

ndrit

e

Sam

ple

Prim

itive

Man

tleS

ampl

eP

rimiti

ve M

antle

Sam

ple

Prim

itive

Man

tle

Mount Arrowsmith

Karmutsen Range

(a) (b)

(c) (d)

(e) (f )

Sam

ple

Cho

ndrit

e




1

10

100

1

10

100

1

10

100



01

1

10

100

1

10

100

1

10

100






18




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39




000

025

050

075

100

125

0 1 2 3 4 5

00

04

08

12

16

0 5 10 15 20 25

MgO (wt)

0

5

10

15

0 50 100 150

Hf (ppm)

Th (ppm)

NbLaNb (ppm)

Zr (ppm)

(a)

(c)

(b)

(d)

Th (ppm)

00

02

04

06

08

10

12

00 01 02 03 04 05



Pillowed flow

NbLa=1

4723A4 5615A12

U (ppm)



19




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39




05128

05129

05130

05131

05132

015 017 019 021 023 025

02829

02830

02831

02832

02833

02834

000 002 004 006 008 010

4

6

8

10

0702 0703 0704 0705 07066

8

10

12

14

5 6 7 8 9 10

12

0

1

2

3

4

5

6

7

0702 0703 0704 0705 0706

(d)

LOI (wt )

87Sr 86Sr

4723A2

Nd

143Nd144Nd

147Sm144Nd

87Sr 86Sr (230 Ma)

(230 Ma)



Pillowed flow

(a)

(c)

176Hf177Hf


176Lu177Hf

Hf (230 Ma)

Nd (230 Ma)

(e)

Hf (i)

(b)



20









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39









4718A2 THOL MA 128 202 0703247 6 00183 070319 460 168 0513004 6 71 01656 051275 81

4718A7 THOL MA 378 283 0703702 8 00387 070358 479 166 0512998 6 70 01742 051274 77

4719A2 THOL MA 327 244 0703811 9 00387 070368 448 161 0512972 6 65 01688 051272 73

4719A3 THOL MA 349 229 0703757 6 00441 070361 422 148 0512972 6 65 01718 051271 72

4720A4 THOL SL 254 215 0703066 8 00341 070295 577 210 0512984 7 67 01662 051273 76

4721A2 THOL SL 158 209 0703076 7 00220 070300 405 146 0512965 7 64 01675 051271 72

4721A4 THOL SL 165 172 0703062 7 00277 070297 548 196 0512933 6 58 01691 051268 66

4720A6 CG SL 611 123 0703121 9 01438 070265 475 168 0512976 7 66 01711 051272 73

4720A7 CG SL 218 157 0703078 6 00401 070295 496 173 0513012 6 73 01735 051275 80

4720A7(dup) CG SL 179 140 0703067 9 00369 070295 456 160 0512994 6 69 01722 051273 77

4720A10 CG SL 011 60 0704294 7 00055 070428 205 57 0513120 7 94 02191 051279 87

4724A3 CG SL 144 135 0703421 8 00310 070332 384 132 0512961 6 63 01757 051270 69

5616A3 CG KR 300 237 0703849 7 00366 070373 382 129 0512983 6 67 01790 051271 72

5617A1 CG SL 200 58 0704241 7 00998 070391 214 606 0513097 7 90 02135 051278 85

4722A4 PIC KR 316 77 0705220 8 01184 070483 107 270 0513115 6 93 02384 051276 81

4722A4(dup) PIC KR 316 77 0705214 7 01184 070483 097 248 0513122 6 94 02361 051277 83

4723A3 PIC KR 165 69 0704209 9 00696 070398 209 591 0513098 7 90 02142 051278 85

4723A4 PIC KR 143 110 0704352 8 00375 070423 214 590 0513060 10 82 02192 051273 76

4723A13 PIC KR 067 63 0704132 8 00312 070403 133 354 0513118 7 94 02268 051278 85

4723A2 HI-MG KR 823 269 0705466 7 00885 070518 199 579 0513059 8 82 02081 051275 79

4722A5 OUTLIER KR 446 191 0703877 7 00678 070366 610 210 0512922 6 55 01756 051266 62



21






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39






(ppm) (ppm) 230 Ma

4718A2 THOL MA 038 253 0283007 4 83 00211 028291 102

4718A7 THOL MA 046 241 0283001 7 81 00271 028288 91

4719A2 THOL MA 040 216 0283079 5 109 00262 028296 120

4719A3 THOL MA 037 212 0283024 9 89 00246 028291 102

4720A4 THOL SL 053 304 0283002 7 81 00247 028289 95

4721A2 THOL SL 036 299 0283004 10 82 00173 028293 107

4721A4 THOL SL 053 279 0283006 6 83 00268 028289 93

4720A6 CG SL 045 238 0283012 5 85 00269 028289 95

4720A7 CG SL 046 223 0283012 6 85 00291 028288 91

4720A7(dup) CG SL 043 235 0283012 4 85 00260 028290 96

4720A10 CG SL 036 100 0283179 7 144 00515 028295 115

4724A3 CG SL 034 141 0283035 8 93 00339 028288 92

5616A3 CG KR 034 270 0283024 7 89 00179 028294 113

5617A1 CG SL 040 140 0283161 4 138 00407 028298 126

4722A4 PIC KR 029 048 0283321 10 194 00857 028294 112

4722A4(dup) PIC KR 029 045 0283350 11 204 00915 028294 113

4723A3 PIC KR 045 098 0283197 6 150 00649 028291 101

4723A4 PIC KR 035 090 0283121 26 123 00561 028287 87

4723A13 PIC KR 035 063 0283250 7 169 00791 028290 97

4723A2 HI-MG KR 043 106 0283186 7 147 00579 028293 108

4722A5 OUTLIER KR 056 315 0283015 6 86 00254 028290 98



22





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39





Pillowed flow

207Pb204Pb

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

208Pb204Pb (230 Ma)

206Pb204Pb (230 Ma)

(a) (b)

(c) (e)

4723A24723A2

4723A2

4723A2

4722A4

4723A4

4722A4

4723A4

4723A134723A3

4723A3

4723A13

1556

1558

1560

1562

1564

1566

1568

186 190 194 198 202 206 2101550

1552

1554

1556

1558

1560

178 180 182 184 186 188 190 192 194

380

384

388

392

396

186 190 194 198 202 206 210374

378

382

386

390

178 180 182 184 186 188 190 192 194

206Pb204Pb(d)

LOI (wt )

0

1

2

3

4

5

6

7

186 190 194 198 202 206 210

4723A2



23






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39






208Pb 2m238U 235U 232Th 206Pb 207Pb 208Pb


204Pbt

230 Ma 230 Ma 230 Ma

4718A2 THOL MA 018 056 071 195369 00021 156105 00017 390684 00035 160 0116 532 18957 15581 38455

4718A7 THOL MA 017 052 054 195133 00016 156070 00015 390697 00042 201 0146 657 18782 15570 38312

4719A2 THOL MA 018 047 068 195780 00015 156130 00012 390359 00032 176 0127 464 18940 15581 38501

4719A3 THOL MA 014 045 052 196614 00017 156066 00015 392027 00042 180 0131 588 19007 15573 38524

4720A4 THOL SL 021 072 065 198169 00012 156218 00010 393997 00026 210 0153 757 19053 15583 38527

4721A2 THOL SL 025 072 091 194972 00019 156084 00015 390661 00039 176 0127 531 18859 15576 38454

4721A4 THOL SL 017 061 054 198552 00009 156229 00008 394709 00020 209 0151 767 19098 15584 38587

4720A6 CG SL 013 045 056 196209 00017 156124 00013 392307 00039 154 0112 544 19062 15584 38603

4720A7 CG SL 013 048 061 196640 00009 156138 00006 392547 00019 142 0103 535 19149 15588 38638

4720A7(dup) CG SL 014 044 061 196951 00006 156157 00006 392975 00022 149 0108 488 19154 15588 38735

4720A10 CG SL 005 011 051 188745 00018 155788 00016 383176 00042 61 0044 143 18652 15568 38153

4724A3 CG SL 009 030 060 192520 00014 155880 00013 389072 00032 97 0070 336 18900 15570 38519

5616A3 CG KR 194845 00007 155986 00006 390679 00015

5617A1 CG SL 191202 00007 155910 00006 384401 00016

4722A4 PIC KR 005 007 017 189514 00017 155852 00017 384063 00041 208 0151 288 18197 15547 38074

4722A4(dup) PIC KR 005 003 016 189539 00013 155890 00012 384186 00029 224 0162 141 18142 15548 38257

4723A3 PIC KR 006 019 032 189873 00012 155820 00011 384434 00027 114 0083 388 18573 15561 37996

4723A4 PIC KR 005 009 191733 00013 155832 00012 384984 00033 359 0261 555 17868 15517 37858

4723A13 PIC KR 003 011 018 189131 00011 155784 00011 383518 00030 92 0067 415 18580 15561 37873

4723A2 HI-MG KR 006 019 009 207321 00037 156656 00030 392295 00073 410 0298 1347 19242 15590 37676

4722A5 OUTLIER KR 033 082 081 196272 00016 156164 00012 392322 00034 263 0191 680 18673 15568 38448



24








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39








25

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)

SOLIDUS




L + Ol + Opx

07

08

09

Pressure (GPa)

10

3

4

5

6

1

SOLIDUS

01

04

0506

L + Ol

2

03

02

PeridotiteKR-4003

0 10 20 30 40MgO (wt)

4

6

8

10

12

14

FeO(wt)



Melt Fraction

2

3 4 5 6

L+Ol+Opx

SolidusSpinel


7

L+Ol

0 10 20 30 4040

45

50

55

60

MgO (wt)

SiO2

(wt)

PeridotiteKR-4003

Melt Fraction

0 10 20 305

10

15

CaO(wt)

MgO (wt)

3

4 5 6 7

2

46

2



Peridotite

SOLIDUS



02

Pressure (GPa)

0302

04

Pressure (GPa)

Picrite

High-MgO basalt

Tholeiitic basalt

(c)

(d)



(a)

(b)

800 850 900

910

920

930

940

950






26







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39







wt

SiO2 470 476 469 478 473 480 463 461

TiO2 068 046 060 046 055 062 193 056

Al2O3 153 143 130 139 141 123 96 117

Cr2O3 010 020 004 009 011 007 026 016

Fe2O3 103 108 089 109 102 090 108 118

FeO 87 90 95 89 90 92 103 101

MnO 015 015 016 019 016 017 018 018

MgO 153 163 174 161 163 168 183 188

CaO 99 98 96 103 99 103 101 100

Na2O 159 090 174 101 131 136 167 104

K2O 007 006 005 011 007 008 041 003

NiO 005 008 008 007 007 010 008 011

Eruption T (8C) 1354 1375 1397 1369 1374 1382 1415 1422

Potential T (8C) 1467 1491 1517 1486 1490 1500 1606


Melt fraction 023 027 026 027 026 027 028

ol addition 42 25 243 08 79 18



27









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39









28




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39




OIB array

PacificMORB(230 Ma)

(0 Ma)

EPR(230 Ma)

-4

-2

0

2

4

8

10

12

14

16

18

20

22

-4 -2 0 2 4 6 8 10 12 14

minus2

0

2

4

6

8

10

12

14

0702 0703 0704 0705 0706

IndianMORB

87Sr 86Sr (initial)

Hf (initial)

(a) (c)

Nd (initial)





1540

1545

1550

1555

1560

1565

175 180 185 190 195 200375

380

385

390

395

175 180 185 190 195 200

(d) (e)

EPR

EPR

206Pb204Pb

208Pb204Pb

206Pb204Pb

207Pb204Pb



East Pacific Rise


Juan de FucaGorda

ε Nd

(initial)


(0 Ma)

NbY

001

01

1

1 10

ZrY

OIB

NMORB

(b)

Iceland array

6



29



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39



1

10

100


1

10

100


(c)

1

10

100



High-MgO lavas


source (07DM+03PM)

source (07DM+03PM)

6 melting

30 melting

(b)

(a)

30 melting

Sam

ple

Cho

ndrit

eS

ampl

eC

hond

rite 20 melting

1 melting




Sam

ple

Cho

ndrit

e

Tholeiitic lavas

Tholeiitic lavas

High-MgO lavas

source (07DM+03PM)




30








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39








31



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39



00

05

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

16

0 2 4 6 8 10 12 14 16 18 20

10

11

12

13

14

15

16

17

18

19

20

0 2 4 6 8 10 12 14 16 18 206

7

8

9

10

11

12

13

14

15

0 2 4 6 8 10 12 14 16 18 20

MgO (wt)

0 10 20 30 40 50


1400

1300

1200

1100

1000

Tem

pera

ture

(degC


Sp (e)

Ol

CpxPlag


TiO2 (wt)

MgO (wt)

Al2O3 (wt) CaO (wt)

FeO (wt)

MgO(a) (b)

(c) (d)

MgO (wt)MgO (wt)

1400

1300

1200

1100

1000

Tem

pera

ture

(degC

)

Residual liquid ()

1220

1190

Ol + Sp


02 wt H2O

no H2O


(f)

0102030405060708090100



plagioclase

accumulatio

n

10

12

14

16

0 10 20 30 40

Al2O3CaO

SrNd

tholeiitic basalts

(g)



32





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39





Daonella beds

Middle Triassic

deeper water



flows


~4 km

~6 km


Karmutsen Formation


Karmutsen Formation

(a) (b)

(c) (d)

subaerial flows




sills



33










34

















































35





















































36



















































37









38






39










34

















































35





















































36



















































37









38






39

















































35





















































36



















































37









38






39





















































36



















































37









38






39



















































37









38






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38






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39

melting history and magmatic evolution of basalts and ... · basalts and picrites from the...

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