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

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hosted mainly in Late Cretaceous dacite and rhyolite subvolcanic dikes and stocks. The significant deposits in the zone are (table
4) (Noklebq and others 1997a, b, 1998): Sn silicate-sulfide and Sn polymetallic vein deposits at Baryllyelakh-Tsentralny,
Bogatyr, Dneprov, Kandychan, Kharan, Khenikandja, Kheta, Khuren. Kuranakh-Sala, Kyurbelykh, Porozhistoe, Svetloe, and
Tigrets-Industriya; a Sn @cism deposit at Ossolony; a rhyolite-hosted Sn deposit at Suvorov; Au-Ag epithemal vein deposifs at
Aids and Zerkalnoe; PbZn-Ag vein or skarn deposits at Bulunga and Tektonicheskoe, granitoid-related Au deposits at Netchen-
I Khaya, Shkolnoe, a porphyry Mo deposit at Tankist; and a Co-Bi-As vein deposit at Verkhne-Seimkan. The Co and Bi deposits,
as at Verkhny Seimkan, art associated with Cretaceous granitoid plutons of the Okhotsk-Chukotka volcanic-piutoaic belt. The
deposits are generally small, and either exhausted, partly mined, or starting to be mined, as at Shkolnoe. Local Sn deposits with
Ag, Pb, Zn, may be of htura economic interest.
I Tig~lndu9@ya Sn P ~~etalllc Vein Deposit
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The small Tlgrets-Iadustriya Sn polymetallic vein deposit (Lychagin, 1967; Plyashkevich, 1990) consists of quartz-
carbonate-sujfide, quartz-sulfide, md sulfide-quartz veins, and lenticular bodies and zones of veinlets which occur in weakly
I metamorphosed Lale Pennian sedimentary rocks intruded by a Late Cretaceous granite porphyry. The ore badies occur along
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northeast-bending fractures, are i00 to 200 m long, and range from 0.1 to 0.8 m thick. Late Cretaceous siliceous lava flows occur
peripheral to the mineralized area. Several Sn and Ag mineral assemblages occur in the deposit. A period of deformation separeled
early and late stages. The early assemblage consists of quartz-cassiterite and polysulfide containing cassiterite, menopyrite,
pyrite, chaJcopyrite, sphalerite, galeaa, canfieldite, Fe-fieibergite, stannite, and pyrargyrite. The late seleno-canfieldite-quarlz
assemblage conlaids q&, pyrite, sphalerite, galena, stannite, selenocanfieldite, and Mn-calcite.
Mandych8n Sn Polpetauk Vein Deposit
Sn polymela1lk veh deposits, as at Kandychan and Kheta, are hosted mainly in Late Cretaceous subvdcank and flow
rocks of modcrakly felsic to felsic composition. The Kandychan deposit (Firsov, 1972; Lugov and others, 1974a, b; N.E. Savva,
written comun., 1980) consists of groups of veins and veinlets which occur in a generally north-south-trending band more than2
km long md from 500 to 600 m wide. The host volcanic rocks are propylitized, silicified, and argiUized. The ore bodies consist of
quartz-chlorile-cassikrites~de veins with various carbonates (calcite, siderite, dolomite), sericite, hydromica, kaohite, dickite,
pyrophyllite, fluorite, and tourmaline. The sulfide minerals are mainly stannite, pyrargyrite, hessite, and argentite; and lesser
pyrite, chalcopyrik, arsenopyrite, marcasite, pyrrhotite, sphalerite, galena, bornite, and covenite. The deposit ia characterized by
high Ag, Bi, Co, and Au. The gulfide veins with colloform cassiterite near the surface change with depth to low-sulfide chlorite
quartz veins with crystalline cassiterite. The deposit is small, is partly mined, and has produced 2,000 tomes Sn.
Suvomv Rhyolite-Hosted Sn Deposit
I Rhyoiite-hosted Sn deposits, as at Suvorov, and Sn polymetallic vein and Sn greisen deposits, as at Dneprwskoe and
Khhdja, are associated with small Cretaceous granitoid plutons. The Suvorov rhyolite-hosted Sn deposit (Lugov and dhm,
1974a, b; Flerov, 1974) consists ofcolloform cassiterite nodules (wood tin) which occur in intensely silicifltd ahd kaolinizod,
fluidal rhyolite, aggIomerate vitric tuff flows, and tuff- and lava-breccia. The host Late Cretaceous volcanic rocks f m various
volcanic vent facies. Cassiterite is associated with fine-grained quartz, hematite, chlorite, kaolinite, pyrite, sod arsampyrite. The
ore is characterized by bigh Fe and In. The deposit is small.
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Shkolnoe GranltolcFRUakd Au and Au
Quam Vein Deposit
The Shkolnoe graaitoid-related Au and Au quartz vein deposit (fig. 95) (Orlov and Epifanova, 1988; S.V. Voroshin and
others, written cornmu, 1990; Palymsky and Palymskaya, 1990; V.A. Banin, written commun., 1993; Gonchwov, 1995;
Goryachev, 1998,2003) wnsists of an en echelon system of quartz veins which trend generally east-west. The vdw occur in a
multipbse grapitoid stock &out 4 km2 composed mainly of granodiorite and adamellite. The stock is intruded by dikos of @mileporphyry,
rhyolite, pegmclrile, aplile, and larnprophyre. The quartz veins are surrounded by zones of beresitic a d argillic
altaation, and skam and greisen alteration also locally is present. The deposit occurred in two stages separated by intnkon of
-whyre dies (Goryachsv, 1998): (1) an older granitoid-related Au vein deposit containing moiybderdte, arsenopyrite,
Itkllingite, native bismuth, Bi-tellurides, and native gold (herein interpreted as part of the Yana-Kolyma tn~3.allogdc belt); (2) the
most economically-irnpwtmt stage, a Au quartz vein deposit containing arsenopyrite, pyrite, galena, sphalerite, gold, electrum,
freibergite, telmhedrik, Pb-Sb md Ag-sulfosalts, argentite, and stibnite. The Au ore bodies extend to greal deplh into a I&-@ talc
of co@cated minemlogy. gtochemistry, and structure. The total reserves are estimated at 32 tonnes Au averaging 29 B/t Au ad
45 g/t Ag. The mine at the deposit has produced 17 t Au and 17 t Ag from 1991 to 1997.