mesozoic magmatic history and metallogeny of the hotailuh
TRANSCRIPT
Mesozoic Magmatic History and Metallogeny of the Hotailuh Batholith (NW BC)Bram van Straaten , Jim Logan and Larry Diakow
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1.Ministry of Energy and Mines, British Columbia Geological Survey , Victoria, BC
For More [email protected]
+1-250-952-0304
Poster presented at the AME BCMineral Exploration Roundup
(Jan. 23 , 2012)
BCGS GeoFile 2012-08
rd
Digital version released Feb., 2012
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Refine temporalLinkIdentify prospectiveProvide geological base to
&
magmatic and geochemical evolutionmagmatism and mineralization
magmatic-hydrothermal systemsinterpret airborne magnetic
survey regional geochemical stream sediment surveyStimulate mineral exploration�
Goals
Geological maps
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Northern Stikine terraneLarge composite batholith within Triassic -Jurassic volcanic and sedimentary rocks
Late Triassic plutonic suiteEarly Jurassic plutonic suiteMiddle Jurassic plutonic suite
Regional geology
Implications for exploration�
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Identified several new Cu,Au mineral occurrences
Presence of significantLate Triassic magmatic-hydrothermal metallogenicevent, similar to elsewherein N. Stikinia
Previously unrecognizedMiddle Jurassicmagmatic-hydrothermalmineralization deservesmore attention
Intrusion-related mineralization(plotted according to age of intrusive host rock or age of spatially associated intrusion)
Airborne magnetics (QUEST-NW block 1)
F
Z
D
F
F
Z190±2
lJ
(l?)mJ
221±3
lmJ
mJ
Jurassic stratified rocks (northwest area) Jurassic stratified rocks (east area)
Triassic Stuhini Group (all areas)
Z217±2
Volcanic rocks (J V)
Volcanic rocks (J V)
Coarse-grained sedimentary rocks (mJ Sc)
Fine-grained sedimentary rocks (mJ Sf)
Coarse-grained sedimentary rocks (mJ Sc)
Fine-grained sedimentary rocks (mJ Sf)
Coarse-grained quartz-bearing sedimentary rocks (lmJ Scq)
Volcanic rocks (J V)
Fine-grained sedimentary rocks (lJ Sf)
Augite-phyric coherent rocks (T STap)
Fine-grained sedimentary rocks (T STsf)
Volcanic rocks (T STv)
Z U-Pb zircon age(this study; Anderson and Bevier, 1992)
D Detrital U-Pb zircon age(Iverson et al., 2012)
F Fossil location(Gabrielse, 1998)
DmJ
DmJ
Cake Hill pluton (LT CH)+ + + + +
v v
v v v
v v v
v v
v v
v v v
v v v
v v
v v
– – –
– – –– –
– –
– – –
– – –– –
–
• • •
• • •• •
• •
• • •
• • •• •
• •
• • •
• • •• •
• •
• • •
• • •• •
• •
v v v
v v v
v v
v v
– – –
– – –– –
– –
– – –
– – –– –
– –– – –
McBride River pluton (EJ MR)
++
+
Gnat Pass intrusive (LT GP)
– – –
– – –– –
– –
– – –
– – –– –
– –
v v v
v v v
v v
v v
v v v
v v v
v v
v v
++
+
100
110
120
130
140
150
160
170
180
190
200
210
220
230
Ag
e (
Ma
)
Jura
ssic
Cre
tace
ou
sTri
ass
ic
Late
Late
Ea
rly
Ea
rly
Mid
dle
Ar-Ar Bt
Ar-Ar Hbl
U-Pb Zrn
Closed symbols: This study (preliminary)
Open symbols: Zagorevski et al. (2011),
Anderson & Bevier (1992),
Anderson et al. (1982)
Timescale after IUGS International
Commission on Stratigraphy (2010)
Gnat Lakes ultramafite (LT GL)
Cpx hornblendite; Cpx-Hbl gabbro
Cake Hill pluton (LT CH)
Hbl Qtz monzodiorite/Qtz monzonite
Gnat Pass intrusive (LT GP)
Hbl (Qtz) diorite/granodiorite, often Pl-Qtz porphyritic
Beggerlay Creek pluton (LT BC)
Websterite; clinopyroxenite; Cpx-Hbl gabbro
McBride River pluton (EJ MR)
Hbl monzogranite/granodiorite
Fine-grained mafic phase (MJ TSf)
Hbl diorite
Mafic phase (MJ TSm)
Hbl-rich (Qtz?) diorite
Central felsic phase (MJ TSc)
Bt Qtz monzonite/Qtz monzodiorite
Potassic phase (MJ TSp)
Bt granite/Qtz syenite/Qtz monzonite
Tees Creek intrusive (MJ? TC)
Altered Hbl-Fsp porphyry
Three Sisters pluton
Middle Jurassic suite
Early Jurassic suite
Late Triassic suite
Geological unitsStratified rocks
Intrusive rocks
Mineral occurrences
More informationBC Ministry of Energy and Mines, byGeological Fieldwork 2011 articlevan Straaten, Logan and Diakow.
Publications CatalogueAvailable online as a downloadable file at
seewww.empr.gov.bc.ca/geology
ReferencesAnderson, Loveridge and Sullivan (1982); Current Research, Part C, Geological Survey of Canada, Paper 82-1C, p.133-137.Anderson and Bevier (1992); Radiogenic Age and Isotope Studies (Report 6); Geological Survey of Canada, Paper 92-2, p.145-152.Gabrielse (1998); Geological Survey of Canada, Bulletin 504, 118pp.International Commission on Stratigraphy (2010); International stratigraphic chartIverson, Mahoney and Logan (2012); B.C. Ministry of Energy and Mines, Geological Fieldwork 2011, Paper 2012-1.Zagorevski, Joyce, Mihalynuk and Logan (2011); AME BC Mineral Exploration Roundup, January 2011, poster presentation.
AcknowledgementsWe would like to acknowledge financial support from Geoscience BC that covered field, analytical and salary costs associated with the Hotailuhproject. Travis McCarron, Catie Young, Meagan Hogg and Olivia Iverson are thanked for their capable assistance during the field season.Thanks to Janet Gabites (UBC PCIGR) for providing Ar-Ar analysis and Ray Donelick, Margaret and Paul O’Sullivan (Apatite to Zircon) forproviding U-Pb analysis. Thanks also to Bob Anderson for sharing his knowledge of the Hotailuh batholith during discussions.
QUEST-NorthwestAirborne
magnetic surveyRegional geochemicalstream sediment survey
Bedrockmapping+ +
Triassic rock-hosted mineral occurrences
Gnat Pass (Cu)Indicated reserves
:Host rock:
Alteration:
Ore mineralogy:
(non-NI 43-
101) 30.4Mt @ 0.389% CuQtz-Pl porphyry
,tourmaline veining, Fe-Carb-cemented breccias
(LT GP)
Silicification
Ccp, Py
Upper Gnat Creek(Au,Cu,Ag)
Size:
Host rock:
Vein with 20 x 20 cmpod of
Hbl Qtzmonzodiorite / Qtzmonzonite
massive-sulphide-cemented breccia
(LT CH)
Pat West (Cu)Size:
Host rock:
Vein mineralogy:
1 m wide,
Bt Qtz monzonite /Qtz monzodiorite
intenselyveined zone
Qtz, Py, Cusulph
(MJ TSc)
[Several 10-100s m gossanousexposures present slightly west]
3 Sisters North (Cu W)±
Size:
Host rock:
Vein mineralogy:
Subvertical, west striking
Bt Qtz monzonite /Qtz monzodiorite
veins (~5% by volume inseveral m wide interval)
Ep,Act,sulph(MJ TSc)
3 Sisters South (Cu Mo)±
Size:
Host rock:
Associated minerals:
Several 20 m wide,
pyritic, subvertical, northstriking fault zones
Stuhini Groupvolcanic rocks
≤
(T STv)
Act
3 Sisters (Cu)Size:
Host rock:Vein mineralogy:
Three m-scale
Fine-grained Hbl diorite
intensely veined / in-situ brecciated exposures with coppersulphides
Qtz, Py Ccp, Ep(MJ TSf)
±
[A 2 x 0.2 km gossanous zone is exposedtowards the north/northeast]
Midde Jurassic rock-hostedmineral occurrences
Mat North (Cu)Size:Host rock:
Associated minerals:
Ore minerals:
cm/dm-sized podsHbl Qtz
monzodiorite / Qtzmonzonite
coarse-grained euhedralBt
Py Bn
(LT CH)
±
Totalmagneticintensity
Firstvertical
derivative
LegendOutline of Mesozoic intrusionsMINFILE showings, prospects
Other mineral occurrences