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

million tonnes grading 0.42% Cu, 0.34 g/t Au. 3.4 g/t Ag, and 0.017% Mo. The deposit is hosted in biotitAmtnblende-plagioclase
porphyry of the Eocene Babine Suite and in adjacent Jurassic sedimentilly rocks. The porphyry, sedimentary rocks, and deposit
are displaced by a fault.
Au-Ag Epithermal Vein Deposits Ass~~fatdd WIM
Quanchus Plutonic Suite
The Qi~anchus Plutonic Suite forms an arcuate chain of large stocks in west-ceatFal Britigh Columbia The phitons in the
suite are similar in composition to plukm in the Nanika suite to the west, but contain more hornblende and biotite; in addition, the
suite contains only minor porphyry Cu-Mo prospects (Woodsworth andothers, 1991). Comaptic with the plutofls of he
Quanchus suite are uplifted and eroded felaic vokanic ceilters hi the Eocene Ootstt Lake Group in the Fade Range. The
significant Au-Ag epithermal vein prospects arc: (1) the Holy Cross and Uduk b deposits (Lam 4 Schmeh, 1995); (2) the
Wolf prospect which is related to resurgent domlng d felsik intrusion within a caldera (Andrew and o~~ 1986); (3) tber
Clisbako prospect which is hosted in felsic valcanics of dtt! Eocene Clisbako formation, and is om of several similsfidqmut8 in a
caldera with a diameter of 40 Ian (Metcalfe and Hickson, 1995); and (4) the Blackdome mine which OWINS m $4 Eoeem &i&rhyolite-volcaniclastic
sequence, which is coeval with the Ootsa Lake and Ctisbako Volcanics to the nmth, and is wntrolled by
doming and normal faulting (Vivian and others, 1987).
Origin of and Tectonic Controls for
Skeena Metallogenic Belt
The Skeena metall~ic belt of porphyry Cu-Mo; porphyry Mo; Ag polymetalLic veils, aad Au-Ag epitbmal wein
deposits occurs in central British Columbia (fig 103) and is associated with several early Tertiary phtouic suites is&
Intermontane Belt in west-central BriM Co-in. The plutonic suites, which consist of the Nanika, Bibhe, Quen&~, and
Goosly Suites (Woodsworth and ohm, 1991; Carter, 19821 are coeval and spatially related to qmjwent v01W rocks,
indicating that the plutons were the roots of f o m volcanic centers. The plutonic suites are canmronly cc~ltmlkd by highgngle
faults which caused uplift and block-faulting in tbe Stikiaia terrane. The plutonic suites and coeval wlcaik Mitshpattof ad
extensive continental-margin arc in tbe Canadian Codha which consisted of the early Tertiary Kamlaop twgmatic belt(Pb&r d
others, 1989; Nokleberg and others, 1994c, 1997~) and Lhe Late Cretacems and early Tertiary ~-~ Casaxb @to& belt
(Nokleberg and others, 19Wc, 1 997c). TbGse v-twit suites m the southem Intermontane Belt we in- as kgh-1evel
products of deep-seated plutoniun and melamorphiam i Je Coast Belt to the west which f o d m a haoqw&w emgat xeW to an
extensional stress field (Woodswortk~ sad o b , 1991).
Nelson Metallogenic Belt of
Ag Polyrnetallic Vein, Ag-Pb-Zn Manto,
Au-Ag Epithermal Vein, Porphyry Mo,
Paleoplacer U. and Related Deposits (Belt NS)
Southern British Columbia
The Nelson metallogenic belt of Ag palymstailic vein; Ag-Pb-Zn manto; Au-Ag epithennrd vein, poqbyry hh,
paleoplacer U and related depoalts (fig. 103; tables 3,4) occm m sauthern British Coluzabia The belt cuntdns sijpfhut Au-Ag
polymetallic vein and manto deposits which occur in two settmgs. Some deposits occur to the east, in or near the MU Jurarwric
Nelson Batholith which is part ofthe Nebon flutonic suite (Woodswo~.tb and others, 1991). Thesignificant deposit13 in the belt we
(table 4) (Nokleberg and others 19a70, b. i998): Au-Ag and Ag polymetallic vein deposits at Ainswmth DWct, Highhad Bell
(Beaverdell), Millie Mack, and Silverton District (Sandon, Siivcr Ridge), a porphyry Mo deposit at C2mni Moly; a Zn-F'bAg
skam and manto deposit at Rloa&! (Blue Bell); and & paleoph U deposit at Lassie Lake area (Blkzard).
Bluebell (Riondel) Zn-Pb-Ag Skarn and Msnto Deposit
The Bluebell (Riondel) Zn-Pb-Ag skam and Pronta deposit (fig. 122) wmists of splsakib, galala, pyrrhotite, pyrite,
arsenopyrite, chalcopyrite and kaebelite which occur in r ~ bodies and ~ in veins controlled t by bddmg, h&ms and open
anticlinal culminations (Hoy, 1980, 1982a; Nelson, 1991; Beaudoin and others, 1992). The manto andvein &posits occur along
bedding or fractures, and in pre-cleformatiad biaccias, and aadchd cuhimtion~ in bly cb'~britla -torn of the Bad&&
Formation, and in quartz-mica schist of the Mohican Funnath A distinctive skarn mineral assemblage iacludcs ppde knebelite (Fe-Mn olivine) and retrograde rninneaotaite (Fe talc), Fe-, Mn-, and Mg-carbonate, cblorib, calcite, aml cplz. A K-Ar
isotopic age of 59 Ma for vein muscovite which cuts a gabbro dyke indicates an Eocene age of miaeralimtion for the Rh&l
deposit and possibly for the district (Beaudoin and others, 1992). The miae at the deposit attained the largtst product@ from a
Canadian Zn-Pb-Ag skam mine. Between 1895 and 1971 estimated production was 4.82 million tonnes of ore. and estimated
reserves are 0.35 million tonnes gnding 6.3% Zn, 5.2% Pb, and 45 dt Ag.