USGS Professional Paper 1697 - Alaska Resources Library

ate and clastic rocks and volcaniclastic deposits of Riphean,
Vendian, and Cambrian age with a combined thickness of as
much as 13 km. The major lithologies are limestone, dolomite,
marl, mudstone, shale, mudstone, siltstone, sandstone,
quartzite, conglomerate, basalt, tuff, Cu-bearing sandstone,
and Cu-bearing basalt. Rare mafic and ultramafic dikes occur.
The units are metamorphosed to lower greenschist facies. The
sulfide deposits, as at Sardana, are interpreted as syngenetic.
The Southeast Missouri Pb-Zn deposits are located in the
upper part of the Oron Formation of Ludlovian age (350-500
m thick), which consists of large black and thin bedded dolomites
and hydrogenic dolomite breccia. Hiod unit is overlapped
by the Hurat Formation that consists mainly of marl.
The Southeast Missouri Pb-Zn deposits of the Sette-Daban
Range metallogenic belt are interpreted as forming from
artesian thermal waters that circulated through the carbonate
rocks of the North Asia passive continental margin. The sediment-hosted
Cu deposits of the Sette-Daban belt are hosted in
volcanic sedimentary rocks of Givetian, Fronian, Famenian
and Turonian age. The significant deposits are in the upper
Famenian and Turonian Menkule suite, which ranges from 100
to 550 m thick and contains coastal-marine and continental
sandstone, tuffaceous sandstone, siltstone, and dolomite. The
basaltic Cu and sediment-hosted Cu deposits are interpreted
as forming during rifting, mainly in the Middle Devonian to
Early Carboniferous (Shpikerman, 1998).
Selennyakh River Metallogenic Belt of Southeast
Missouri Pb-Zn, Stratabound Hg and Au, and
Pb-Zn Vein Deposits (Belt SEL) Northwestern
Part of Russian Northeast
The Selennyakh River belt metallogenic belt of diverse
lode deposits, including Mississippi Zn-Pb, stratabound Hg
and Au, and Pb-Zn vein deposits (fig. 16; tables 3, 4) occurs
in the northwestern part of the Russian Northeast (Shpikerman,
1998). The metallogenic belt is hosted in the Omulevka
terrane of the Kolyma-Omolon superterrane in early through
late Paleozoic, passive continental-margin carbonate and shale
(Nokleberg and others, 1994c, 1997c; Shpikerman, 1998).
The significant deposits are (table 4) (Nokleberg and others
1997a,b, 1998) (1) stratabound Hg deposits, such as the
Gal-Khaya carbonate-hosted Hg deposit, (2) small Southeast
Missouri type Pb-Zn occurrences as at Kondakovskoe, (3) Pb-
Zn vein deposits as at Chistoe, and (4) Au quartz vein deposits
as at Khatynnakh-Sala. This metallogenic belt, which needs
further study, occurs along a sublatitudinal strike for more than
600 km (fig. 16).
Gal-Khaya Carbonate-Hosted Hg Deposit
The Gal-Khaya carbonate-hosted Hg deposit (Babkin,
1975) consists of a zone of quartz-carbonate breccia and veins
that occurs along the contact of Early Silurian limestone and
calcareous shale. The zone is 600 m long, 60 to 80 m wide,
Middle and Late Devonian Metallogenic Belts (387 to 360 Ma; figures 16, 17) 59
dips 75°, and is concordant to host rock bedding. The ore
occurs in cylindrical ore shoots, mainly in carbonate breccia
cemented with calcite and quartz-calcite. The main ore mineral
is cinnabar. Also present are metacinnabar, galkhaite (Hg, Cu,
Zn; As, Sb), stibnite, realgar, orpiment, pyrite, chalcopyrite,
fluorite, barite, native gold, tennantite, sphalerite, bornite,
chalcocite, covellite, malachite, and azurite. Gangue minerals
include quartz, calcite, dolomite, barite, dickite, kaolinite, and
bitumen (anthraxolite). The (syngenetic) deposit is interpreted
as forming in the Late Devonian or Carboniferous (Shpikerman,
1998), or as an epigenetic deposit that formed in the Late
Cretaceous (Galkin, 1968).
Kondakovskoe Southeast Missouri Pb-Zn Occurrence
The Kondakovskoe Southeast Missouri Pb-Zn deposit
(Bakharev and others, 1988) consists of sulfide disseminations
and pockets in Devonian limestone, which is locally metamorphosed
to marble. The deposit is localized along the southern
contact of the Early Cretaceous Ulakhan-Siss granodiorite
intrusion. The mineralized layer is several hundred meters
long and consists of two mineral assemblages—(1) galenasphalerite;
and (2) less common pyrite-tetrahedrite. The
deposit contains as much as 0.1 percent Cd, 0.05 to 1 percent
Pb, 0.08 to 1.5 percent Zn, and 0.01 to 0.3 percent Sb.
Chistoe Pb-Zn Vein Deposit
The Chistoe Pb-Zn vein deposit (Shpikerman, 1998)
consists of a galena vein that occurs in a shear zone in Ordovician
limestone locally metamorphosed to marble. The vein
varies from 10 to 20 m thick and is about ten meters long. The
ore minerals include galena, which is predominant, and also
pyrite, sphalerite, chalcopyrite, cerussite, and smithsonite.
Oxidized minerals are locally abundant.
Khatynnakh-Sala Au Quartz Vein Deposit
The Khatynnakh-Sala Au quartz vein deposit (Nekrasov,
1959, 1962; O.G. Epov and others, written commun., 1964)
occurs in anticlinal domes and is controlled by bedding-plane
faults. The ore bodies include 30 veins, lenses, lenticular
bodies, and stockworks. The veins are generally not more
than 1 m thick, generally 15 to 20 m long, and not more than
30 to 40 m long. Most of the veins and host rocks are isoclinally
folded. The host rocks include Ordovician and Silurian
amphibole-mica-carbonate shale and limestone locally
metamorphosed to marble. Two levels of intensely sulfidized
shale, from 0.4 to 6 m thick and as much as 250 m long, also
occur in the deposit. Post-mineralization diabase and diorite
porphyritic dikes are present, which are probably Late Jurassic-to-Early
Cretaceous in age. Besides pyrite and pyrrhotite,
the ore minerals are arsenopyrite, galena, fahlore, sphalerite,
and gold. Gangue minerals constitute 95 percent of the deposit
and include quartz, albite, ankerite, barite, and fluorite. Pyrite
is altered to pyrrhotite, and metamorphic actinolite, zoisite,
biotite, sphene replace gangue minerals along with recrystal-