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

mines are interpreted as distal skarns relative to the W skarn; however others have interpreted the Pb-Zn deposits as syngenetic
(Dawson, 1996a).
Phoenix-Greenwood Cu Deposit
The Phoenix-Greenwood Cu-Au skarn deposit consists of chalcopyrite, pyrite, pyrrhotite, magnetite plus minor sphalerite
and galena which occur in a garnet-rich calc-silicate skarn assemblage of andradite, clinozoisite, diopside and quartz (Church,
1986; Schroeter and Lane, 1991; MINFILE, 2002). The skarn hosted by Triassic carbonate, clastic, and volcanic rocks of the
previously-accreted Quesnellia terrane in proximity to contacts with Middle Jurassic and mid-Cretaceous granitoid intrusive rocks.
Production from 1893 to 1985 was 270,000 tonnes Cu, 36 tonnes Au, and 117 tonnes Ag. The deposit age is interpreted as Middle
Jurassic to Early Cretaceous.
Mineral King Zn-Pb-Ag Skam and Manto Deposit
The Mineral King deposit consists of sphalerite, galena and pyrite with bournonite and rare meneghinite which occur in
steeply-dipping pipes or as manto-style replacements along steeply dipping shear zones associated with a synclinal wedge between
two faults. The deposit is hosted in the Middle Proterozoic Mount Nelson Formation composed of dolomite and dolomitic
quartzite. The mine at the deposit produced an estimated 2.1 million tonnes grading 4.12% Zn, 1.70% Pb, and 24.8 g/t Ag (Fyles,
1960). Estimated current reserves are 72,576 tonnes grading 34.3 g/t Ag, 2.5% Pb, and 4.5% Zn.. No intrusive rock is exposed,
but the deposit is interpreted as a Zn-Pb skarn and manto distally related to a buried intrusion (Dawson and others, 1991) of the
Bayonne Plutonic Suite.
Origin of and Tectonic Controls for
Bayonne Metallogenic Belt
The Bayonne metallogenic belt is hosted in the extreme, southern part of the Omineca-Selwyn plutonic belt (fig. 62). The
iithophile geochemistry of the plutonic suite is reflected in the abundance of porphyry Mo and related skarn deposits. The
Omineca-Selwyn plutonic belt extends from the southern part of the Canadian Cordillera, across Interior Alaska, and northwestward
into the Russian Northeast, and consists chiefly of granodiorite, granite, quartz syenite and minor syenite plutons of Early to mid-
Cretaceous age (1 10-90 Ma; Monger and Nokleberg, 1996; Nokleberg and others, 1994c; 2000). The plutons in the belt form an extensive
linear array of discrete intrusions, and many plutons exhibit S-type character. Extrusive equivalents (such as the South Fork Volcanics in
the Yukon Territory) are rare. The plutons commonly have high initial strontium ratios (about 0.710), indicating partial derivation from
old cratonic crust (Armstrong, 1988: Woodsworth and others, 1991). The spatial location of the belt, about 200 km west of the eastern
limit of Cordilleran deformation, and chemistry suggests an anatectic origin of partial melting of cratonic crust during thickening caused
by Cretaceous contraction (Monger and Nokleberg, 1996; Nokleberg and others, 2000) which was associated with orthogonal
convergence between the Farallon Oceanic Plate and North America (Englebretson and others, 1985; 1992), and subsequent
regional extension (Pavlis and others, 1993). Other metallogenic belts of granitic-magmatism-related deposits hosted in the
Ornineca-Selwyn plutonic belt in the Canadian Cordillera, Alaska, and the Russian Northeast include the Cassiar, Selwyn, Tombstone,
and Whitehorse belts (fig. 62; table 3).
Early Late Cretaceous
Metallogenic Belts (100 to 84 Ma;
Figures 79,80)
Overview
The major early Late Cretaceous metallogenic belts in the Russian Far East, Alaska, and the Canadian Cordillera are
summarized in table 3 and portrayed on figures 79 and 80. The major belts are as follows. (1) In the Russian Southeast, the Kema
(KM), Lower Amur (LA), Luzhkinsky (LZ), Sergeevka (SG), and Taukha (TK) belts, which contain a large array of granitic-
magmatism-related deposits, are hosted in or near the East Sikhote-Aline volcanic-plutonic belt and are interpreted as forming
during subduction-related granitic plutonism which formed the East Sikhote-Aline continental margin arc. (2) In the same region
was the Aniva-Navil (ANN) metallogenic belt of volcanogenic Mn and Fe and Cyprus massive sulfide deposits that are interpreted
as forming in guyots, and oceanic crustal and island arc assemblages that were subsequently tectonically incorporated into the
Aniva and Nabilsky terranes accretionary wedge and subduction zone terranes. (3) Also in the same region, continuing on from
the late Early Cretaceous was the Badzhal-Ezop-Khingan (BZ-KH) belt of granitic-magmatism-related deposits, which is hosted in
the Khingan-Okhotsk volcanic-plutonic belt, and is interpreted as forming in the Khingan continental-margin arc. (4) In the
Russian Northeast are the Chaun (CN), Dogdo-Erikit (DE), Korkodon-Nayakhan (KN), Koni-Yablon (KY), Okhotsk (OH),
Omsukchan (OM), Verkhne-Kolyma (VK) zones which constitute various parts of the Eastern Asia belt. In the same region and
also part of the are the Eastern Asia metallogenic belt are the Adycha-Taryn (AT), Chokurdak (CD), and Vostochno-Verkhoyansk