USGS Professional Paper 1697 - Alaska Resources Library

Eastern Asia-Arctic Metallogenic Belt: Dogdo-
Erikit Metallogenic Zone of Au-Ag Epithermal
Vein, Sn-polymetallic vein (Southern Bolivian
type?), and Volcanic-Hosted Hg (Plamennoe
type) Deposits (Belt DE), West-Central Part of
Russian Northeast
The Dogdo-Erikit metallogenic zone of Au-Ag and Ag-
Sb epithermal vein and volcanic-hosted Hg deposits (fig. 79;
tables 3, 4) extends for about 1,000 km and is much as 50 to
70 km wide in a narrow band from the northwest to the southeast
in the west-central part of the Russian Northeast (Goryachev,
1998, 2003). This belt is hosted in the volcanic rocks of
the Uyandin-Yasachen volcanic belt and the clastic deposits of
the Inyali-Debin flysch basin (both parts of the Indigirka-Oloy
sedimentary-volcanic assemblage) and the underlying carbonate
rocks of the passive continental-margin Omulevka terrane
of the Kolyma-Omolon superterrane.
The Dogdo-Erikit zone contains significant Au-Ag epithermal
vein deposits, as at Kysylga, Tikhon, and Shirokoe,
Sn-polymetallic vein (Southern Bolivian type?) deposits at
Solkuchan, and a volcanic-hosted Hg deposit Dogdo (table 4)
(Nokleberg and others 1997a,b, 1998). The Au-Ag epithermal
vein deposits are closely related to Late Cretaceous hypabyssal
rhyolite bodies with K-Ar isotopic ages of 90 to 56 Ma. The hypabyssal
rhyolites crosscut contact metamorphic aureoles of older
Cretaceous granitoid plutons (Gamyanin and Goryachev, 1988).
The Dogdo volcanic-hosted Hg deposit and similar deposits are
hosted in Early Cretaceous(?) felsic volcanic rocks that are associated
with rhyolite and andesite hypabyssal bodies with K-Ar
ages of 125 to 63 Ma (Ganeev, 1974). The volcanic-hosted Hg
deposits are small, uneconomic, and occur in the northwest part
of the metallogenic belt, which overlies the Selennyakh metallogenic
belt of preaccretionary Hg deposits (fig. 79). The Dogdo-
Erikit metallogenic zone is interpreted as forming in a transverse
(orthogonal) limb of the Cretaceous Okhotsk-Chukotka volcanicplutonic
belt (Goryachev, 1998, 2003).
Kysylga Au-Ag Epithermal Vein Deposit
The Kysylga Au-Ag epithermal vein deposit (Shoshin
and Vishnevsky, 1984; Yu.A. 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 as much as 400 m long. The veins are composed
of quartz, calcite, and ore minerals (1 to 5 percent) including
arsenopyrite, pyrite, Ag-tetrahedrite, pyrrhotite, sphalerite,
galena, chalcopyrite, boulangerite, Ag-jamesonite, and a low
gold fineness (638). The veins strike from roughly east-west
to northeast and dip steeply to south. The veins exhibit breccia
or, less commonly, comb and massive structures and often
grade into stringer lodes. The deposit occurs in feathered fissures
of a northwest-striking major fault and is hosted in Late
Triassic sandstone and siltstone that exhibits linear folding and
intense contact metamorphic alteration adjacent to a granitic
Early Late Cretaceous Metallogenic Belts (100 to 84 Ma; figs. 79, 80) 197
intrusive. Wallrocks display sericite, chlorite, and feldspar
alteration. Average grades are 3.0 to 84.5 g/t Au, 1 to 37 g/t
Ag; 0.01-0.1 As; 0.01 to 0.04 percent Sb; 0.002 percent Sn,
and 0.03 percent Pb.
Solkuchan Sn-Ag Polymetallic Vein (Southern Bolivian
type?) Deposit
The Solkuchan Sn-polymetallic vein (Southern Bolivian
type) deposit (S.M. Khaustova and Yu.A. Vladimirtseva, written
commun., 1987; Nekrasov and others, 1987; Shkodzinsky
and others, 1992) consists of three steeply dipping quartzcarbonate-sulfide
veins that occur in an Early Cretaceous
subvolcanic dacite stock. The veins are as much as 3.4 m
thick and as much as 900 m long. The ore minerals are pyrite,
pyrrhotite, arsenopyrite, sphalerite, galena, Ag-tetrahedrite
(31 to 39 percent Ag), boulangerite, pyrargyrite, canfieldite,
electrum (fineness 685), cassiterite, covellite, scorodite, cerussite,
smithsonite, melnikovite, and Fe-hydroxides. Anomalous
Cu, Sb, Ge, and Id are present. The deposit is of medium size.
Average grades are 200 g/t Ag, from 0.04 to 2.16 percent Sn,
0.03 to 2.71 percent Pb, and 0.02 to 5.85 percent Zn.
Dogdo Volcanic-Hosted Hg (Plamennoe type) Deposit
The Dogdo volcanic-hosted Hg (Plamennoe type) deposit
(Klimov, 1979; Yu.A. Vladimirtseva, written commun., 1987)
consists of four lenticular and podiform ore bodies that occur
in strongly silicified Late Jurassic andesite-dacite tuff. The ore
bodies are 20 to 100 m long and 2 to 8 m wide. The ore minerals
are quartz, calcite, barite with disseminations and stringers
of cinnabar, pyrite, arsenopyrite, sphalerite, galena, and chalcopyrite.
The ore district is characterized by a close correlation
between Hg content and barite. Mineralization is controlled by
a northwestern thrust fault, secondary quartzite occurrences,
and occurrence of ore bodies along feathering fractures of the
thrust fault. The deposit is of minor to medium size. Average
grades are 0.35 to 0.90 percent Hg.
Eastern Asia-Arctic Metallogenic Belt: Okhotsk
Zone of Au-Ag Epithermal Vein Deposits (Belt
EAOH), Southeastern Part of Russian Northeast
The Okhotsk zone of Au-Ag epithermal vein deposits (fig.
79; tables 3, 4) occurs in the southeastern part of the Russian
Northeast (Goryachev, 1998). The metallogenic belt is more
than 1,500 km long and locally more than 100 km wide. The
metallogenic belt occurs mainly in the rear of the Okhotsk-
Chukotka volcanic-plutonic belt (Nokleberg and others, 1994c,
1997c). The significant deposits in the zone are (table 4) (Nokleberg
and others 1997a,b, 1998): Au-Ag epithermal vein deposits
at Agat, Aldigych, Burgagylkan, Druchak, Evenskoe, Irbychan,
Julietta, Karamken, Kegali, Khakandzhinskoe (Khakandzha),
Kolkhida, Krasivoe, Nevenrekan, Oira, Olyndja, Sentyabr,
Spiridonych, Teply, Utessnoe, Verkhnenyotskoe, Vetvisty, and
Yurievka; a granitoid-related Au deposit at Maltan Stock; epi-