mesozoic magmatic history and metallogeny of the hotailuh

Mesozoic Magmatic History and Metallogeny of the Hotailuh Batholith (NW BC)Bram van Straaten , Jim Logan and Larry Diakow

1 1 1

1.Ministry of Energy and Mines, British Columbia Geological Survey , Victoria, BC

For More InformationBram.vanStraaten@gov.bc.ca

+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