Metallogenesis and Tectonics of the Russian Far East, Alaska, and ...

Buhenchuk, 1991; Diron and others, 1995; MINFILE, 2002). The deposit is hosted in biotite-feldspar porphyry of the Eocene
Babine Plutonic Suite and the adjacent Jurassic metasedimentary rocks and metavolcanic rocks of the Hazelton Group. A K-Ar
biotite isotopic age of 5 1.0 Ma for the porphyry is interpreted as the age of deposit. The deposit exhibits pervasive potassic
(mainly biotite) alteration with a surrounding, concentric halo of chlorite and sericite-carbonate alteration. The alteration coincides
with a two-km-wide pyrite halo which surrounds the deposit (Dirom and others, 1995). A supergene chalcocite zone caps the
deposit and extends to depths of 50 to 70 meters. Higher Cu grades occur in a 60 to 90 m-thick, flat-lying area which is connected
to a central pipe-like zone which is centered on the western contact of the intrusion. Past production was 28.7 million tonnes
grading 0.46% Cu.
EOCENE
BABINE IGNEOUS SUITE
r 1
Post stockwork bme plaQmdase porphyry
d~ke. black, hard.
Quartz.biotlbe. d~l"po'-p"~
(QFP. QBFP). hte Post slockwork
Explos~on breccia. Bwiders and asbblea
of BFP ~n a tufkeous matrix.
Wte plsgasgse ~
qu--==itw* 8
~ e b pemsb m k
n w -
Biotite pbgtodase porphyry, biotite
aiwatim M e plag~w pqhm
undivided.
Rhyolite and rhyodaal~ with spares pkgiiodase
-ts in dl-. ptugs, anc~ mer.
CRETACEOUS
SKEENAGROUP (AIM?)
Wemed~ate fm~mental vdcanic rocks.
Bladt shale, $&&one. pate green tuff.
JUFU4sSlC
Hazelton group
Srn1thet-s Forrnatlon (m):
I., Dark brown graywacke, highly
NmFomrahon?(-)
end vdeaniclaotic rack,
Telkwa FormaHn (Sinsmurlen):
Kotslne Fades (made)
Dark ween merlm hd. sendslone.
Figure 121. Bell Copper porphyry CuAu deposit, Skeena metallogenic belt, Canadian Cordillera. Schematic gymlogic map Of am
aro'ound open pit and altwatlon halos. Adapted from Butrenchuk (1991).
Oranisle Porphyry Cu-Au (Mo) Deposit
The Granisle porphyry Cu-Au (Mo) deposit consists of chalcopyrite, bornite and pyrite with low grade Au and Ag and
local minor molybdenite which occur in quartz-filled fractures (Carson and Jambor, 1974; Fahrni and others, 1976; EMR Caaads,
1989; Dawson and others, 1991; Dirom and others, 1995). The deposit is associated with Eocene Babine porphyry intrusions (with
K-Ar isotopic ages of 5 1.2 Ma) which intrude volcanic and sedimentary rocks of the Early Jurassic Hazelton Group. Cdinsd
estimated production and reserves re 66.2 million tonnes grading 0.42% Cu, 0.12 g/t Au, 1.12 g/t A& and 0.009 g/t Mo. The
deposit is centered on the contact between biotite-feldspar porphyry and an earlier quartz diorite phase. A central potassic
alteration zone is successively rimmed by a quartz-sericite-carbonate-pyrite alteration zone and by a ohlorite-carbona~~ote
alteration zone (Dirom and others, 1995).
Morrison Porphyry Cu-Au (Mo) Deposit
The Morrison Porphyry Cu-Au (Mo) deposit consists of chalcopyrite and pyrite which occur in a ~tockurofk
of' ireinlets
and fractures, and as disseminations (Carter, 1982; EMR Canada, 1989; Ogryzlo and others, 1995). Estimated resources are 86