USGS Professional Paper 1697 - Alaska Resources Library

Origin of and Tectonic Controls for Khamna River
Metallogenic Belt
The carbonatites and alkalic igneous rocks of the Khamna
River metallogenic belt intrude Late Proterozoic and early
Paleozoic sedimentary deposits of the folded margin of the
North Asian Craton Margin (Shpikerman, 1998; Verkhoyansk
fold belt, unit NSV). U-Pb isotopic studies of the carbonatites
and ores yield an age of 417 to 240 Ma, and K-Ar isotopic
studies yield an age of 350 to 280 Ma (Elyanov and Moralev,
1973). Because coeval, rift-related basaltic rocks formed in
adjacent areas, the Khamna River metallogenic belt is interpreted
as forming during rifting of the North Asian Craton
during the Late Devonian to Early Mississippian. The sedimentary
rocks of the Verkhoyansk fold belt are apparently
tectonically detached from crystalline basement of craton. The
fold belt is separated from the Siberian platform by a Late
Cretaceous, west-verging thrust belt.
Sette-Daban Range Metallogenic Belt of
Southeast Missouri Pb-Zn, Sediment-Hosted Cu,
and Basaltic Cu Deposits (Belt SD) Southern Part
of Eastern Siberia
The Sette-Daban Range metallogenic belt of Southeast
Missouri Pb-Zn, sediment-hosted Cu, and basaltic Cu deposits
(fig. 16; tables 3, 4) occurs in the southern part of eastern
Siberia (Nokleberg and others, 1994c, 1997c; Shpikerman,
1998) in the North Asian Craton Margin (Verkhoyansk fold
belt, unit NSV). The metallogenic belt trends south to north
for more than 700 km along the Sette-Daban Mountain Range.
The deposits, of Late Proterozoic to Early Carboniferous
age, occur at different stratigraphic levels of the North Asian
Craton Margin (Verkhoyansk fold belt, unit NSV). The major
Southeast Missouri Pb-Zn deposits are at Lugun, Sakyryr,
Segenyakh, and Urui; the major sediment-hosted Cu deposit
is at Kurpandzha; and the major basaltic Cu deposit is at
Dzhalkan (table 4) (Nokleberg and others 1997a,b, 1998). The
Southeast Missouri Pb-Zn deposits are the dominate deposit
type in the metallogenic belt. The Southeast Missouri Pb-Zn
deposits at Urui and Lugun occur in Vendian dolomite of the
Udom Formation, and the Southeast Missouri Pb-Zn-fluorite
occurrences at Segennyak and Sakyryr are hosted by Late
Silurian dolomite of the Oron Formation. The sediment-hosted
Cu deposits are associated with basaltic Cu deposits, which
usually occur at the same or nearby stratigraphic levels. The
sediment-hosted Cu deposits are hosted in Late Devonian and
Early Carboniferous sandstone and shale.
Sardana Missouri Pb-Zn Deposit
The Sardana Missouri Pb-Zn deposit (fig. 26) (Kuznetsov
and Yanshin, 1979; Ruchkin and others, 1979; Kutyrev and
others, 1989) consists of disseminated, banded, massive, breccia,
and ore, and in stringers that occur within and adjacent
to a dolomite bioherm, which is from 50 to 80 m thick. The
Middle and Late Devonian Metallogenic Belts (387 to 360 Ma; figures 16, 17) 57
bioherm is hosted in the Late Proterozoic (Late Vendian)
dolomite of the Yudom Formation. The ore bodies are lenticular,
ribbon-like, and cylindrical in form and are mostly
confined to the overturned limb of a syncline. The limb dips
eastward at 75 to 85°. The ore bodies are as much as 40 m
thick and are 200 to 300 m long at depth. Drilling indicates
additional ore bodies occur at a depth of 200 to 300 m. Most
of the ore is associated with metasomatic, sugar-textured
dolomite and zebra (brown and white striped) dolomite. The
main ore minerals are sphalerite, galena, calcite, and dolomite,
and subordinate ore minerals are pyrite, marcasite, arsenopyrite,
quartz, and anthraxolite. Oxidized ore minerals include
smithsonite, cerussite, anglesite, goethite, hydrogoethite, and
aragonite. Low-grade disseminations occur in Late Proterozoic
(Late Vendian) dolomite for many kilometers in both limbs
and in the axis of a north-south-trending syncline, which is 3
km wide and more than 10 km long. The deposit is medium
to large with reserves of more than 1.0 million tonnes Pb+Zn
and a Pb:Zn ratio of 1:3-4. The dolomite of Yudom Formation
is 200 m thick and transgressively overlies Late Proterozoic
(Late Riphean) quartz and quartz-feldspar sandstone and siltstone
that in turn is conformably overlain by Early Cambrian
variegated clay and carbonate rocks. The deposit intruded by
sparse diabase and dolerite dikes.
Urui Southeast Missouri Pb-Zn Deposit
The Urui Southeast Missouri Pb-Zn deposit (Ruchkin
and others, 1977; Volkodav and others, 1979; Bogovin and
others, 1979; N.D. Kobtseva and T.G. Devyatkina, written
commun., 1988) consists of stratified ribbon-like deposits,
from 2 to 40 m thick and 0.5 to 1.2 km long, which occur in
metamorphosed Late Proterozoic (Vendian) dolomite. The ore
bodies are conformable to host rocks and strike 30 to 45°NW;
and commonly wedge out at a depth of 30 to 40 m. The
deposits vary from massive to pocket-stringer to disseminated
to banded. Galena and sphalerite are the main ore minerals;
pyrite, marcasite, arsenopyrite are secondary; and pyrrhotite,
chalcopyrite, and electrum are scarce. Calcite, quartz, and
anthraxolite also occur. The deposit is medium to large with
an average grade of 9.9 to 25.6 Pb; 6.4 to 21.3 percent Zn; 6.8
to 200 g/t Ag; as much as 10 g/t Ge. The deposit is associated
with a significant recrystallization of dolomite and formation
of peculiar zebra dolomite rocks. The general structural pattern
of deposit controlled by monoclinal strike of sedimentary
rocks to the west and by numerous post-ore faults that trend
roughly east-west and strike northwest. Local Paleozoic diabase
dikes in area.
Kurpandzha Sediment-Hosted Cu Deposit
The Kurpandzha Southeast sediment-hosted Cu deposit
(Kutyrev, 1984; Ioganson, 1988) consists of more than three
stratified horizons of finely disseminated to massive copper
ore that is hosted in Late Devonian to Early Carboniferous
coastal and deltaic sandstone. The main ore minerals are
chalcocite, bornite, chalcopyrite, and pyrite. Ore bodies range