By Sergey M. Rodionov1, Alexander A. Obolenskiy2
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Taryn Metallogenic Belt ofClastic-Sediment-Hosted Sb-AuDeposits(Belt Tar) (Russia, Verkhoyansk-Kolyma Region)This Aptian to Late Cretaceous metallogenic belt is related to veins and replacements in the Kular-Nera continental margin turbidite terrane and Verkhoyansk fold and thrust belt in the North Asian Craton Margin. The belt extends northwest for 500 km along most of the Kular-Neta terrane. The belt contains numerous major Au-Sb deposits at Tan, Maltan, Kinyas’-Yuryakh, Sarylakh, Kyunkugur, Kim, El’gi-Tonor, Tobychan, Lower Tordocha, Kekhtey, Kemyustakh, Byindzha, Aulachan, Dzholakag, Nitkan, Uzlovoye, Burgavliyskoye, Sentachan, and Markovskoye, and lesser Ag and Ag-Sb polymetallic deposits at Kupol’noye and Dichek. The major deposits are at Sarylakh, Senatachan, and Kupol'noe. Senatachan Clastic-Sediment-Hosted Sb-Au DepositThis deposit (Berger, 1978; Zharikov, 1978; Indolev and others, 1980; Maslennikov, written commun., 1985; Shur, 1985) consists of two rod-like veins that range from 85 to 200 m long and 0.2 to 3.1 m thick. The veins occur in shear zones that strike northwest, dip 60 to 80° northwest, and extend to a depth of 600 m or more. The main ore minerals are stibnite and quartz, with lesser ankerite, muscovite, pyrite, arsenopyrite, dickite, and hydromica, and rare sphalerite, Au, chalcostibnite, berthierite, tetrahedrite, zinkenite, jamesonite, aurostibnite, and chalcopyrite. Wallrocks exhibit quartz, carbonate, hydromica and dickite alteration. Disseminated pyrite and stibnite occur in aureoles around deposit. The deposit hosted in Late Triassic (Norian and Rhaetian) clastic rock that is deformed into northwest-trending, gently-plunging folds. The deposits occur along the northwest-trending Adycha-Taryn fault and are conformable to folding. Average grade of 3.2 to 40.3% Sb with locally up to 30% Sb and 50 g/t Au. The deposit is medium size, has been mined, and has reserves of 100,000 tonnes Sb. Origin and Tectonic Controls for Taryn Metallogenic BeltThe belt is interpreted as forming during post-accretionary extension related to initiation of opening of Eurasia Basin. REFERENCES: Berger, 1978, 1986; Indolev and others, 1980; V.V. Maslennikov, written commun., 1985; Shur, 1985; Gamyanin and Goryachev, 1988; Parfenov and others, 2001. Selennyakh Metallogenic Belt ofCarbonate-hosted Au-Sb-Hg,Volcanic-Hosted Hg, Au-Ag EpithermalVein, and Ag-Sb Vein Deposits(Belt SE) (Russia, Verkhoyansk-Kolyma Rgion)This Aptian to Late Cretaceous metallogenic belt is related to veins and replacements in the Omulevka passive continental margin terrane of the Kolyma-Omolon superterrane and adjacent terranes. The belt contains carbonate and hosted Au-Sb-Hg (Gal Khaya, Pologoye, and Arbat deposits), volcanic-hosted Hg (Dogdo deposit), and Ag-Sb vein (Kysylga deposit) deposits. The Selennyakh metallogenic belt was previously named the Uyandina-Yasachnaya Hg-ore belt (Obolenskiy and Obolenskaya, 1972; Indolev and others, 1980). The belt is 80 km wide, extends for 200 km, and is related to igneous rocks in the Late Jurassic volcanic rock of the Uyandina-Yasachnaya volcanic belt that unconformably overlies the Omulevka terrane. In the northwestern of the belt is the Sakyndzha ore district (Au-Hg-Sb) and to the southeast, the Dogdo (Hg-Au-Ag) ore district. In other areas belt are numerous Hg-Au occurrences. Kysylga Ag-Sb Vein DepositThis deposit (Shoshin and Vishnevsky, 1984; E. Vladimirtseva, written commun., 1985; Nekrasov and others, 1987; Gamyanin and Goryachev, 1988.) consists of veins in a zone that varies from 0.60 to 1.25 m thick and up to 400 m long. The veins consist of gangue quartz and calcite with about 1 to 5% arsenopyrite, pyrite, Ag-tetrahedrite, pyrrhotite, sphalerite, galena, chalcopyrite, boulangerite, Ag-jamesonite, and Au (fineness of 638). The veins strike roughly east-west to northeast and dip steeply south. The veins exhibit brecciaiated or, less commonly, comb and massive structures, and often grade into stringers. The deposit occurs along feathered fissures in a northwest-striking major fault that cuts Late Triassic sandstone and siltstone. Host rocks are folding and are intensely contact metamorphosed adjacent to a granitic intrusive. Wallrocks exhibit sericite, chlorite, and feldspar alteration. The average grade is 3.0 to 84.5 g/t Au, 1 to 37 g/t Ag; 0.01 to 0.1 As; 0.01 to 0.04% Sb; 0.002% Sn, and 0.03% Pb. Origin and Tectonic Controls for Selennyakh Metalogenic BeltThe belt is interpreted as forming during post-accretionary extension related to initiation of opening of Eurasia Basin. The belt extends northwest along the Omulevka terrane composed of early and middle Paleozoic carbonate rock that is unconformably overlain by Late Jurassic volcanic and sedimentary rocks of the Uyandina-Yasachnaya volcanic belt. REFERENCES: Obolensky and Obolenskaya, 1972; Indolev and others, 1980; Shoshin and Vishnevsky, 1984; Parfenov and others, 1999, 2001; Nokleberg and others, 2003. Khandyga Metallogenic Belt ofAg-Sb Vein, Carbonate-Hosted As-AuMetasomatite, Clastic-Sediment-HostedSb-Au, and Clastic Sediment-Hosted Hg±SbDeposits(Belt Kha) (Russia, Verkhoyansk-Kolyma Region)This Aptian to Late Cretaceous metallogenic belt is related to veins and replacements in the southern Verkhoyansk fold and thrust belt in the North Asian Craton Margin. The metallogenic belt extends longitudinally for 250 km and ranges up to 30 km wide. The belt occur along the Sette-Daban tectonic zone that contains early to middle Paleozoic carbonate rock, and in the adjacent, eastern Kylakh tectonic zone that contains Riphean clastic and carbonate rock, and in an area of periclinal closure containing Carboniferous, Permian, and Triassic marine clastic rock. The major deposits are at Senduchen, Khamamyt, Svetloe, and Khachakchan. Senduchen Clastic-Sediment-Hosted Sb-Au DepositThis deposit (V. Korostelev, written commun., 1963) consists of quartz-carbonate veins composed of orpiment, stibnite, realgar, arsenopyrite, sphalerite, enargite, chalcopyrite, and jamesonite. Individual orpiment concretions range up to 10 tonnes. The veins intrude dark-gray Silurian limestone, range up to 3.5 m thick, and occur in a fault zone that cuts an anticline. The deposit is small with an average grade of 10 to 58% As and 2.9% Sb. Seikimyan Clastic Sediment-Hosted Hg±Sb DepositsThis deposit (Klimov, 1979; E. Vladimirtseva, written commun., 1987) consists of stringers and disseminations with quartz, dickite, cinnabar, calcite, and pyrite, and rare galena, sphalerite, and arsenopyrite. Deposit hosted in feathered shear and breccia zones in sandstone with dimensions of 0.4-7 by 50-200 m. Deposit occurs on northeastern limb of an anticline formed in Late Triassic sandstone and siltstone. Deposit is bounded by faults that occur parallel to the major, regional Bryungadin fault. Grade ranges up to 0.1-0.5% Hg. Origin and Tectonic Controls for Khandyga Metallogenic BeltThe belt is interpreted as forming during post-accretionary extension related to initiation of opening of the Eurasia Basin. The belt occurs in veins and replacements in the southern Verkhoyansk fold and thrust alon the Sette-Daban tectonic zone. REFERENCES: Ozerova and others, 1990; Parfenov and others, 2001; Nokleberg and others, 2003. |