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

extension. The Coryell Suite is interpreted as the rear or back-a~ part of the Coast-North Cascade plutonic belt. The vein and
manto deposits which occur in, or around the Middle Jurassic Nelson Batholith, including those in the Silverton, Ainsworth,
Slocan, and Sandon districts, were originally interpreted as forming during the Middle Jurassic inbusion of the batholith and
associated granitoid dikes (Cairnes, 1934; Hedley 1947, 1952). However, recent isotopic studies suggest: (1) an Eocene age for
mineralization for deposits in the district (Beaudoin and others, 19921, including Qe large Bluebell (hondel) skarn and manto;
and (2) that the deposits formed during intrusion of (Eocene) mafic and lamprophyric dikes.
To the west in the Okanagan Valley several other Au-Ag cpithermal vein dep0si.k are hosted by Eocene trachyte volcanic
rocks of the Marron Formation which is genetically related to the alkalic Coryell Plutonic Suite (Woodswortb and others, 1991;
Church, 1973). The Au-Ag epithennal vein deposils include the Vault (Pantdeyev. 199 1) and Dusty Mac (Zhang and others,
1989) deposits. The igneous rocks and associated deposits are interpreted as forming during Eocene regional extension associated
with the low-angle Okanagan shear zone (Tempelman-Kluit and Parkinso& 1986; Purish and others, 1991).
Early to Middle Tertiary
Metallogenic Belts 52 to 23 Ma;
Figures 102,103)
Overview
The major early Tertiary metallogenic belb in the Rusian Far East and the Canadian CordiUera are summarized in table
3 and portrayed on figures 102 and 103. Tbe major belts are es follows. (1) In the Russian Southeast, the Central Sakhaiio (CS)
belt, which contains Au quartz veln and talc deposits, is hosted in deformed units of the Aniva subduction zone terrane, and is
interpreted as forming in collisional event dwng the early Tertiary(?) accretion of outboard terns to the east. (2) On the
southern Karnchatka Peninsula in the Russian Northeast, the Sredhy metellogenic belt of Au quartz vein and metamorphic REE
vein(?) deposits is hosted in the Sredimy-Kamchatka terrane and is ~ntupreted as forming during accretion of the outboard
outboard Olyutorka arc and generation of hydrothermal fluids. (3) Also on the southern Kamchatka Peninsula in the Russian
Northeast, the Kvinumsky metallogenic belt of hornblende peridotiie Cu-Ni and gabbroic Ni-Cu deposits, is hosted in corhndite
norite-diorite intrusions which intrude the older metamorphic and granitoid rocks of the Sredinny-Kamchatka metamorphic
terrane. The belt is interpreted as forming during backarc intrusion related to subduction beneath the Karnchatka Peninsula part of
Northeast Asia continental margin arc. (4) In the Russian Northeast, the Canal Koryak (CKY) belt, which contains grenitiemagmatism-related
deposits, is hosted in the Kamchatkak-Koryak volcanic-plutonic belt, and is intmpmted r*, forming along a
transform continental-margin arc. (5) In the Russian Northeast, tbe Olyutor (OT) belt, which contains granitic-magmatism-related
and clastlc sediment-hosted Hg deposits, is hosted in tbe East Kamchatka volcanic and sedimentary besin, and is interpreted as
fonn~ng during subduction-related granlllc plutonkm that fonned the Karnchatka Pthula part of Northeast Asia continental
margin. (6) In the central Canadian Cordillera, the Pinchi Lake belt, which contains Hg epithermd vein, SbAu vein, silicacarbonate
Hg deposits hosted in, or near shear zoos, is interpreted as forming during banscurrent faulting dong Cslscade volcanicplutonic
belt. And (7) in the southern Canadian Cordillera, the Owl Creek (OC) belt, which also contains granitic-magmatismrelated
deposits, is hosted in the Cascade volcanic-plutonic bck md is interpreted as forming hing subduction-related granitic
plutonism which fonned the Cascade continental margin arc. ln the below descriptiolu of rnetallogmic belts, a few of the noteable
or signficant lode deposits (table 4) are described for each belt.
Metallogenic-Tectonic Model for
Early to Middle Tertiary (52 to23 Ma;
Figure 123)
During the early to mlddlc Tertiary (middte Eocene b the early Miocene - 42 to 23 Ma), the major metdogenic-tectonic
events were (fig. 123; table 3): (1) accretion of the Olyutorka island arc; (2) coatinualion of a series of ~~llthental-mm arcs,
associated metallogenic belts, and companion subduction-zone assemblages around the Cucum-North Pacific; (3) continuation of
sea-floor spreading in the Arctic and eastern Pacific Oceans; (4) establishment of a new continental marein in the northern and
eastern parts of the Circum-North Pacific es the m l t of he disappearance of the Kula Ocean plate and inception of subduction of
the leading edge of the Pacific Ocean plate; (5) continuation of dextral h-anspression between tbe Pacific Ocean plate (PAC) and
the North American continental margin in the eastern part of the Chcum-North Pacific; and (6) a change ta orlhogonal
transpression between the Pacific Ocean ptte and the Southern Alaska continental margin because of countmlockwise rotation of
Western Alaska.
At about 50 Ma (Vogt and others, 1979), the Gakkel Ridge (GK; northern extension of the Atlantk ~ d - b Ridge) m
was Initiated and sea-floor spreading extended tnto the Eurasia Basin (eb) in tk Arctic ocean, thereby multing in the NO&
American-Eurasia plate boundary in the Russian Nodcast. The exact location of the Euierpole cbged throughout the
Cenozoic, thereby resulting in regional changes in he stra regime (Savostin and others, 1984; H M and others, 1990).
Analysis of marine magnetic anomalies in the Eurasia Basin suggests that the region underwed extension from about 56 to 36 hb
(Savostin and Drachev, 1988a, b; Harbert and others, 1990; Fujita and others, 1997).