USGS Professional Paper 1697 - Alaska Resources Library

194 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera
Origin of and Tectonic Controls for Lower Amur
Metallogenic Belt
The Cretaceous granitoid rocks hosting the Lower Amur
metallogenic belt are part of the East Sikhote-Alin volcanicplutonic
belt (fig. 79) of Late Cretaceous and early Tertiary
age that is described in the above section the origin of the
Taukha metallogenic belt. Other related, coeval metallogenic
belts hosted in the East-Sikhote-Aline volcanic belt are the
Kema (KM), Luzhkinsky (LZ), Sergeevka (SG), and Taukha
(TK) belts (fig. 79; table 3). The differences between the
coeval metallogenic belts are interpreted as the result the igneous
rocks that host these metallogenic belts intruding different
bedrock. In contrast to these other coeval and related belts, the
Lower Amur metallogenic belt occurs where Cretaceous granitoid
rocks of the East Sikhote-Aline belt intrude the Amur
River and Kiselyovka-Manoma accretionary-wedge terranes.
Metallogenic Belt Formed in Late Mesozoic
Oceanic Crust and Island Arc Terranes, Russian
Southeast
Aniva-Nabil Metallogenic Belt of Volcanogenic
Mn and Fe and Cyprus Massive Sulfide Deposits
(Belt ANN), Sakhalin Island, Southeastern Part of
Russian Far East
The Aniva-Nabil metallogenic belt of volcanogenic Mn
and Fe, and Cyprus Cu massive sulfide deposits occurs on
Sakhalin Island in the southeastern part of the Russian Far East
(fig. 79; tables 3, 4) (Nokleberg and others, 1997b, 1998). The
belt occurs in the Aniva subduction-zone terrane and in the
related Nabilsky accretionary-wedge terrane in the central part
of the island (Nokleberg and others, 1994c, 1997c). The volcanogenic
Mn deposits, as at Bereznyakovskoe and Lyukamskoe
(Sidorenko, 1974), generally consist of small quartz-rhodonite
lenses, with surficial pyrolusite and psilomelane, which are
derived from carbonate and Mn-oxide assemblages. Associated
with the occurrences are hydrothermal quartz, sericite, and
carbonate alteration. The volcanogenic Fe deposits are mainly
quartz-hematite lenses that are derived from carbonate and Feoxide
assemblages. During subsequent accretion and companion
metamorphism, the carbonate-oxide assemblages recrystallized
to hematite-rhodonite-quartz and hematite-quartz.
The Cyprus massive sulfide deposits, as at Novikovskoe and
Rys’e (Sidorenko, 1974), occur in highly deformed mafic
volcanic rocks with chalcopyrite and pyrite and subordinate
galena,bornite, tetrahedrite, chalcocite and covellite.
Both the volcanogenic Mn and volcanogenic Fe deposits
occur in fault-bounded jasper-bearing volcanic assemblages.
The Cyprus massive sulfide deposits occur in fault-bounded
fragments of mafic volcanic rocks. The host rocks are highly
deformed fragments of Late Cretaceous turbidites, limestone
blocks derived from oceanic crustal and island-arc assem-
blages (including blocks of volcanic-jasper deposits) and
metamorphosed gabbro and ultramafic igneous rocks. These
units are interpreted as subducted oceanic-crust and island-arc
fragments now contained in the highly deformed Aniva and
Nabilsky subduction-zone and accretionary-wedge terranes.
These terranes are interpreted tectonically linked to the Cretaceous
East Sikhote-Alin volcanic-plutonic belt (Nokleberg and
others, 1994c, 1997c, 2000).
Metallogenic Belts Formed in Late Mesozoic
and Early Cenozoic Olyutorka Island Arc,
Russian Northeast
Koryak Highlands Metallogenic Belt of Zoned
Mafic-Ultramafic PGE and Cu Massive Sulfide
Deposits (Belt KH), East-Central Part of Russian
Northeast
The Koryak Highlands metallogenic belt of zoned
mafic-ultramafic PGE deposits occurs in the southern Koryak
Highlands in the east-central part of the Russian Northeast
(fig. 79; tables 3, 4). The belt extends northeast for 1,000 km
from the Sredinny Range in central Kamchatka Peninsula to
the Koryak Highlands in the northern Peninsula (Bundtzen
and Sidorov, 1998; Kozin and others, 1999; Melkomukov and
Zaitsev, 1999). The belt is hosted in the Olyutorka subterrane
of the Olyutorka-Kamchatka island-arc terrane (Nokleberg and
others, 1994c, 1997c). The metallogenic belt contains several
PGE and Cr deposits that occur in zoned, Alaskan-Uralian
type plutons composed of gabbro, dunite, and clinopyroxenite.
The significant deposits in the belt are the Snezhnoe zoned
mafic-ultramafic Cr-PGE deposit, the Galmeononsky-Seinavsky
zoned mafic-ultramafic PGE (Alaskan-Uralian PGE),
and a rare gabbroic Cu massive sulfide prospect at Karaginsky
(table 4) (Melnikova, 1974; Kepezhinskas and others, 1993;
L.V. Melnikov, written commun., 1993; Nokleberg and others
1997a,b, 1998; Bundtzen and Sidorov, 1998). The Karaginsky
deposit consists of sulfide lenses hosted in spillite and siltstone,
and sulfide disseminations hosted in serpentinized ultramafic
olistoliths. The sulfide minerals are chalcopyrite and pyrite,
local sphalerite, and locally abundant magnetite, and, in addition
to Cu, the deposit contains Ni, Co, PGE, Zn, Au, and Ag.
Snezhnoe Podiform Cr Deposit
The Snezhnoe zoned mafic-ultramafic Cr-PGE deposit
(Kutyev and others, 1988a,b; Kutyev and others, 1991)
occurs in a small round stock, about 2 km wide, composed
of ultramafic rocks. The stock is zoned with a core of dunite,
and an outer zone of wehrlite-pyroxenites and pyroxenites.
The ultramafic rocks in the stock intrude Late Cretaceous
volcanogenic-sedimentary rocks that are contact metamorphosed
near the stock. Chromite occurs in the dunite core and
as small lenses and veins in streaky and veinlet structures.