USGS Professional Paper 1697 - Alaska Resources Library

tonnes Au and an average grade of about 17 g/t Au and 15.7 g/t
Ag. Since 1996, the Kubaka deposit has been developed under a
joint venture agreement between the Kinross Gold Corporation
of Canada and a consortium of Russian firms under the Omolon
Mining Company. The joint venture is the first Western and
Russian mining venture to succeed in the Russian Federation.
The stratified volcanic rocks and subvolcanic caldera
rocks yield Rb-Sr isochron ages of 332 to 344 Ma. Post-ore
alkalic basalt dikes exhibit K-Ar isotopic ages of 124-155 Ma.
Adularia from ore vein samples exhibit Ar-Ar ages that range
from 110 to 175 Ma, with plateau ages ranging from 110 to
130 Ma. Cretaceous rhyolite and alkalic basalt dikes occur
within and beyond the mineralized tectonic block. Basalt
1,000 m
1,000 m
0
1,000 m
50
70
28
10
Middle and Late Devonian Metallogenic Belts (387 to 360 Ma; figures 16, 17) 45
10
Kubaka River
dikes cross the mineralized veins and are themselves cut by
later, Au-poor quartz-carbonate veins and veinlets. The age of
mineralization is interpreted as Late Devonian to Early Carboniferous
because fragments of Au-bearing calcedonic quartz
occur in the adjacent conglomerates, which contain Early-
Middle Carboniferous fossils.
Olcha Au-Ag Epithermal Vein Deposit
The Olcha Au-Ag epithermal vein deposit (Zagruzina and
Pokazaniev, 1975; Pokazaniev, 1976a,b; I.N. Kotlar, written
commun., 1984) consists of steeply dipping quartz, carbonatequartz,
and adularia-quartz veins and stockwork zones ranging
Aulandja River
0 5 km
N
10
Alkalic gabbro
Korbin Formation, Coaly shale
(Lower Carboniferous)
Kubaka Sequence, trachy
basaltic tuff, and trachyandesite
(Lower Carboniferous)
Trachydacite
Rhyolite
Tuffaceous sandstone
Rhyolite ignimbrite and tuff
(Devonian)
Biotite-amphibolite gneiss
(Archean)
Ore bodies
Fault
Thrust fault
Contact
Strike and dip of bedding
Figure 21. Kubaka Au-Ag epithermal vein deposit, Kedon metallogenic belt, Russian Northeast. Schematic geologic map and
oblique view cross sections. Adapted from I.N.Kotlyar and N.E. Savva (written comm. 1994) and Sidorov and Goryachev (1994).
See figure 16 and table 4 for location.