USGS Professional Paper 1697 - Alaska Resources Library

152 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera
cutting quartz veins with gold, galena, arsenopyrite, pyrite,
tetrahedrite, sulfosalts, carbonates, and albite that are hosted
in Early Permian sandstone beds. The veins occur in anticlinal
hinges, are as much as 1 km long, and range from 0.2 to 1 m
thick, sometimes as much as 10 m thick. Sulfides constitute as
much as 5 percent of the veins. The Au quartz vein deposits
are not economic, but the source for the placer Au mines of the
Verkhoyansk district.
Chochimbal Au Polymetallic Vein Deposit
The Au polymetallic vein deposit at Chochimbal (Goryachev,
1994, 2003) consists of interbedded shallow-dipping,
steeply dipping, cross cutting carbonate-quartz-sulfide veins
that are hosted in mid-Carboniferous clastic rocks. The ore
bodies vary from 0.1 to 2.8 m thick and from 400 to 500 m
long. The major minerals are quartz, siderite, sulfides, pyrite,
arsenopyrite, Fe-sphalerite, and galena. Less common minerals
are chalcopyrite, pyrrhotite, tetrahedrite, bournonite, native
gold, and boulangerite.
Imtandzha Sn Polymetallic Vein Deposit
The Imtandzha Sn polymetallic vein deposit occurs in
a zone of an intense fissures along the axis of an anticline
that is about 500 m wide and 2 km long. Coeval granodiorite
porphyry dikes both cut and are cut by the polymetallic vein
deposits (Goryachev, 1998, 2003). Early-stage polymetallic
veins are mostly conformable, whereas late stage, cross cutting
veins are less common. The early-stage veins range from 0.01
to 0.85 m thick. The major minerals are galena, sphalerite, and
siderite; minor minerals are quartz, tetrahedrite, pyrite, arsenopyrite,
and boulangerite. The late stage veins contain quartz,
chlorite, pyrite, arsenopyrite, galena, cassiterite, tourmaline,
and stannite and range from 0.1 to 0.6 m thick.
Origin of and Tectonic Controls for Verkhoyansk
Metallogenic Belt
The Verkhoyansk metallogenic belt is hosted in rocks
late Paleozoic to early Mesozoic clastic sedimentary rocks
that are weakly metamorphosed, lower greenschist facies with
development of metamorphic chlorite and rare biotite. Permian
and Triassic diabase dikes are widespread along with isolated
Cretaceous granitoid plutons and variable-composition dikes.
The Au quartz vein deposits of the Verkhoyansk metallogenic
belt are interpreted as forming during regional deformation
and metamorphism associated with accretion of the Kolyma-
Omolon superterrane to the Verkhoyansk fold belt of the North
Asian Craton Margin (Goryachev, 1998, 2003). The slightly
younger Au and Sn polymetallic vein deposits of the Verkhoyansk
metallogenic belt are interpreted as forming during
the Main part of the Early Cretaceous Verkhoyansk collisional
granitic belt (vk) (Nokleberg and others, 1994c, 1997c). The
belt is interpreted as forming immediately after the Late Jurassic
accretion of the Kolyma-Omolon superterrane to the North
Asian Craton Margin (Nokleberg and others, 1994c, 1997c).
Yana-Kolyma Metallogenic Belt of Au Quartz Vein,
Sn Vein and Greisen, W Vein, Granitoid-Related
Au, and Clastic-Sediment-Hosted Hg Deposits
(Belt YA), Central Part of Russian Northeast
The Yana-Kolyma metallogenic belt of mainly Au quartz
vein, lesser Sn vein, Sn greisen, granitoid related Au, W vein
deposits, and clastic-sediment-hosted Hg deposits (fig. 61;
tables 3, 4) occurs in the central part of the Russian Northeast
(Goryachev, 1998, 2003). The Yana-Kolyma belt is hosted
in the upper Paleozoic through middle Mesozoic rocks of
the Kular-Nera accretionary-wedge terrane of the Kolyma-
Omolon superterrane (Nokleberg and others, 1994c, 1997c).
Major, wide shear zones, distinct folds, and numerous granitic
intrusions characterize the host rocks of the metallogenic belt.
These structures and intrusions are interpreted as forming during
collision of continental blocks in the Late Jurassic to Early
Cretaceous. The collisional zone contains a major belt of Early
Cretaceous granitoid plutons that are mainly high alumina and
S-type with lesser I-type plutons (Shkodzinsky and others,
1992). The latter are associated with numerous andesite and
granitic porphyry dike suites.
The numerous Au quartz vein lode and related placer
Au deposits in the Yana-Kolyma metallogenic belt are sites
of extensive Russian Northeast Au production (Shilo, 1960;
Firsov, 1957, 1985; Goryachev, 1998, 2003). The total production
has been more than 2,570 tonnes of placer Au and
about 100 tonnes of lode Au. The most important lode Au
deposits in the metallogenic belt are (1) the Natalka deposit,
in production since 1945, which has produced about 75
tonnes of Au, (2) the Igumen deposit, with a production of 11
tonnes Au, (3) the Rodionov, Vetrenskoye, and Utin deposits
with combined production about 8 tonnes Au, and (4) other
deposits at Srednikan, and Shturm. Mining has ceased at all
lode deposits except at Natalka and Svetloye. However, the
majority of the deposits are not thoroughly prospected. The
significant deposits in the belt are (tables 3, 4) (1) Au quartz
vein deposits at Aleshkino, Bazovskoe, Badran, Burkhala,
Chai-Yurya, Chelbanya, Daika Novaya, Darpir, Degdekan,
Dirin-Yuryak, Djelgala-Tyellakh, Dorozhnoe, Ekspeditsionnoe,
Goletsov (Golets), Igumen, Imtachan, Kamenistoe,
Khangalass, Khaptagai-Khaya, Kholodnoe, Kontrandya,
Laryukov, Lazo, Maldyak, Mitrei, Natalka, Nadezhda, Pavlik,
Pil, Rodionov, Sana, Srednekan, Stakhanov, Shturm, Sokh,
Svetloe, Taboga, Talalak, Tokichan, Tumannoe, Tunguss,
Tuora-Tas, Uchui, Utinka (fig. 68), Verkhne-Khakchan,
Vetrenskoe, Yugler, Yukhondja, Zatessnoe, and Zhdannoe, (2)
granitoid-related Au deposits at Delyuvialnoe and Ergelyakh,
(3) Sn and Sn-W greisen deposits at Alyaskitovoe, Baryllyelakh,
Bekkem, and Kere-Yuryak, (4) Sn quartz vein deposits
at Butugychag, Burgavli, Burkat, Medvezhje, and Svetloe, (5)
a Sb-Au vein deposit at Krokhalin, (6) a W vein and greisen
deposit at Bokhapcha, and (7) a clastic sediment-hosted Hg
or hot-spring Hg deposit at Kuzmichan (Nokleberg and others
1997a,b, 1998).