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

Metallogenic Belts Formed in Tertiary
Backarc Rifting and Continental-Margin
Transform, and Transcurrent Faulting,
Russian Southeast
Kvinumsky Metallogenic Belt of
Hornblende Peridotite and Gabbroic
Cu-Ni Deposits (Belt KV)
Southern Kamchatka Peninsula
The Kvinumsky metallogenic belt of hornblende peiidotite and gabbroic Cu-Ni deposits occurs in the southem
Kamchatka Peninsula and is associated with early Tertiary intmsive rock (fig. 102; tables 3,4) (Bundtzen and others, 2003a, b).
The major Cu-Ni deposits, at Shanuch, Kvinum, and Kuvalorog, are associated with cortlandite-norite-diorite intrusions which
intrude the older metamorphic and granitoid rocks of the Sredimy-Kamchatka metamorphic ternme (Nokleberg and oihem,
1997b, 1998,2000). An incremental 40~r)9~r isotopic age for the host intrusive rock ranges from 60-40 Ma (Bundtzen and others,
2003a, b). The deposits generalty consists of pentlandite, Zn-bearing chrome spinel, pyrrhotite, chalcopyrite, and bomite which
occur in veinlets and as disseminations in hornblendite-pridotite-mrite-diorite intrusions. The deposits are small and the sdfides
occur mainly as disseminations in gabbro (Shcheka and Chubarov, 1984). Ni is less than 1 .ON, and Cu is less than 1.0%. Tbe
sulfide disseminations contain up to 1 g/t Au and up to 6 glt Pt. The region containing these deposits is inaccessible and poorly
explored. The Kvinumsky metallogenic belt of hornblde peridotik and gabbroic Cu-Ni deposits is herein interpreted as forming
during backarc intrusion related to subduction beneath the Kamchacka Peninsula part of Central Kamchatka continental margin
arc.
Central Koryak Metallogenic Belt of
Igneous Arc Deposits (Belt CKY)
East-Central Part of Russian Northeast
The Central Koryak metallogenic be!t of igneous-arc-related deposils (fig. 102; tables 3,4) occurs in the Koryak
Highlands in the east-central part of the Russian Northeast. The beh extends From the Penzhina Inlet to the Aaadyr Bay for about
1,000 krn and is composed mainly of Sn polyrnetallic, Au-Ag qithermal, Hg-Sb vein, and porphyry Mo-Cu deposits. The
significant deposits in the belt are (table 4) (Nokleberg and orhers 1997a, b, 1998): Sn polyrnetallic vein deposits at Ai~tvetkin,
Berezovaya, Khrustal (Khrustalnoe), Parkhonai, Reznikov, and Unnei; Au-Ag epilhermal vein deposits at Ametistovoe, lvolga,
Orlovka, and Spmt; volcanic-hosted Hg deposits at Agranai and Lamut; clastic sediment-hosted Hg or hot-spring Hg? &posits at
Krassnaya Gorka, Lyapganai, and Neptun; silica-carbonate Hg deposits at Pervenets and Tarnvatney; and porphyry Cu-Mo
deposits at Kuibiveen, Lalankytap, and Rzhavy.
The metallogenic belt is hosted in or near he calc-alkaline magmatic rocks of the western part of the Kamchatka-Koryak
volcanic belt (fig. 102) (Pozdeev, 1986, 1990; Filatova, 1988; Naklebwg and others, 1994c, 1997~). Various, isolated ring,
volcanic-plutonic, and volcanic structures host about a third of the metallogenic bell. The Kamchatka-Koryak volcanic belt
unconformably overlie nappes and thrust slices of previous-accreted flypch, island arc, and ophiolite kmes. The Sn polymetallic
and Au-Ag epithermal vein deposits occur minty along the sautkm flank of tbe metallogenic belt in a region underlain by a
thick crust composed of a granitic and metamorphic rocks up to 40 km thick. The northern part of the belt consists of the
Parkhonai district which contains Sn, Au-Ag, Sb, and Hg polymetallic vein, and clastic-sediment-hosted Hg deposits. The Central
Koryak metallogenic belt also has potential for undiscovered Sn lode deposits.
Sn polymetallic Deposits
The Sn polymetallic vein deposits are hosted by metasedirnentary rocks, sibcic and intermediate volcanic rocks, and
granite porphyry and rhyolite stocks and dikes which occur above concealed granitic batholiths (Lashtabeg and otbers, 1987). The
significant Sn polymetallic deposits arc at Ainatvetkin, Reznikov. Khstal, and Unnei. The deposits tend to be enriched in Ag, In,
Bi, and sometimes Au.
Ainatvetkin Sn polymetallic Deposit
The Sn polymetallic deposit at Alnatvetkin (Lugov and others, 1974; Lugov, ed., 1986) consists of cassiterite-bearing
sulfide-chlorite-quartz veins and fracture zones which are up to a few hundred m long and range 1.0 to 6.0 m thick. The ore
minerals are cassiterite, magnetite, pyrrhoiibe, chalcopyrite, galena, sphajerite, arsenopyrile, wolframite, scheelitt, pyrite, skumite,
canfieldite, pyrargyrite, gold, and native copper. The cassiterite-chlorite-quartz veins and fracture zones contain up to 10 % sulfide
minerals. Most economically important are brecciated zones with fragmcnb of metasomatically altered rocks and qw-chlorite
cement with sulfides. The deposit is bosted in complexly-folded Late Cretaceous (Santouian through Carnpanian) sandstone a d
shale which is overlain by Late Eocene and Oligocene rhyolite, rhyodacite, rhyodacite tuff, and ignimbrite. The Late C remus