Metallogenesis and Tectonics of the Russian Far East, Alaska, and ...

(Nokleberg and others, 1994c, 1997~). 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 which are derived from carbonate and Fe-oxide assemblages.
During subsequent accretion and companion metamorphism, the carbonate-oxide assemblages recrystauized to hematite
rhodonite-quartz and hematite-quartz. The Cyprus massive sulfide deposits, as at Novikovskoe and Rys'e (Sidorenko, 19741,
occur in highly-deformed matlc volcanic rocks with chalcopyrite and pyrite, and subordinate galena, bornite, tetrahednte,
chalcocik 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 highlydeformed
firagrnents of Late Cretaceous turbidites, limestone blocks derived from oceanic crustal and island arc assemblages,
including blocks of volcanic-jasper deposits, and metamorphosed gabbro and ultramafic igneous rocks. These mils 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 volcanicplutonic
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 Mafk-Uftramaftc PGE and
Cu Massive Sulflde 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 Karnchatka Peninsula to the Koryak Highlands in the northern Peninsula (Bundtzen and Sidorov, 1998;
Kozin and others, 1999; Mekomukov and Zaitsev, 1999). The belt is hosted in the Olyutorka subterrane of the Olyutorka-
Karnchatka island-arc terrane (Nokleberg and others, 1994c, 1997~). The metallogenic belt contains several PGE and Cr deposits
which occur in zoned, Alaskan-Uratian type plutons composed of gabbro, dunite, and clinopyroxenite. The significant deposits in
the belt ue the Snezhnoe zoned mafic-uktramafic Cr-PGE deposit, the Galmeononsky-Seinavsky zoned mafic-ulbamafic PGE
(Alaskan-Uralim PGE), end a rare gabbroic Cu massive sulfide prospect at Karaginsky (table 4) (Melnikova, 1974; Kepezhinsh
and others, 1993), L.V. Mehikov, written commun., 1993; Nokleberg and others 1997a, b, 1998; Bundtzen and Sidorov, 1998).
The Karaginsky deposil consists of sulfide lenses hosted in spillite and siltstone, and sulfide disseminations hosted in
serpsntinizcd ultramafic olistolitbs. Tbe sulfide minerals are chalcopyrite and pyrite, local sphalerite, and locally abundant
magnetite, aad. In addition to Cu, the deposit contains Ni, Co, PGE, Zn, Au, and Ag.
Smzhnoe Podfirm 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 dunitc, and an outer zone of
wehrlite-pyoxenites and pyroxenites. The ultramafic rocks in the stock intrude Late Cretaceous volmnogenic-sedimentary rocL
which are contact metamorphosed near the stock. Chromite occurs in the dunite core and occurs as small lenses and veins in
streaky and veinlei structures. These ore bodies range up to 1 m wide and several meters long. Fermginous chromite occurs with
up to 48% Cr&. Titawmagnetite and Cu sulfides occur in the peripheral pyroxenites. PGE minerals occur in association with
chromite arid form in chrome-spinel as small idiomorphic crystals, and as xenomorphic inclusions in interstices. Fa and Pl alloys
are prdwnmant and conlain inclusions of native 0s. The chrome-spinel interstices are is dominated by cperryijte and
teiraferroplatinum. PGE grains range up to 1 rnm diameter. PGE minerals are similar in composition to those in podifonn G
deposits in southeastern Alaska and in the Urals Mountains.
Galmeononsky-Sainavsky PGE Occurrences
The Galmeonsky-Seinavsky PGE (Alaskan PGE) occurrences are located in zoned mafic-ultramafic complexea in the
geograpbc center of the Koryak Highlands metallogenic belt (locally in Russia called the Koryak-Kamchatka platimun bell)
(Bundtzen and others, 2003a. b). The surface area of the Galmeonsky pluton is about 45 km2, and the pluton is about 16 krn l q
and 3 lo 4 km wide. An 40~r/39~r isotopic age of 60-73.9 Ma has been obtained for the pluton (Bunchzen and others, 2003b) The
pluton con& a &mile core which comprises about 70 percent of the body and in the periphery is dunite which is snccessivcly