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

interpreted as vents. The deposit contains estimated reserves of 2.5 million tomes grading 2% Cu, 0.5% Zn, 0.5 g/t Au, 9 g/L Ag.
The deposit is interpreted as a Cyprus(?) massive sulfide deposit (Hay, 1991).
Adams Plateau SEDEX Zn-Pb-Ag Deposits
Several SEDEX Zn-Pb-Ag deposits, which occur in the Admu Plateau area, are hosted in clastic metasedirnentary-
sequences of probable Cambrian age and lower Eagle Bay Assemblage (Schiarizza and Preto, 1987; kby, 1991) in the Kootenay
terrane, and Devonian and older magmatic arc rocks in the Yukon-Tmans terraae in the Canadian Cordillera. The assemblage is
correlative in past with the Nisutlin Assemblage of the Yukon-Tanana t eme (Wheeler and McFeely, 1991). The si@kant
deposits are two previously-producing, small mines at Mosquito King and Lucky Coon.
Origin of and Tectonic Setting for
Kootenay-Shuswap Metallogenic Belt
A diverse group of volcanogenic d rclalcd mimd &posits occur in the KootenayShuswap metallogmic belt. Becaw of a
wide range of age of host rocks and deposibs, this mtrUogenic belt may be divided into two rnetitllogenjc belts, one of Cambrian
age and the other of Devonian and Mississippian age.
The Kuroko massive sulfide wits in the KootcoayShuswap metallogenic belt are basted in Devonian and
Mississippian felsic to intermediak metavalcanic units. n e a&lc-alkaline igneous-arc rocks are interpreted as part of tbs: extfmive
middle Paleozoic continental-margin arc which extd fw several thousand km along the North American bton Margin (Grantz
and others, 1991 ; Rubin and others, 1991; Plafber and Berg, 1994; Nokleberg d others, 1994c, 1997c; Monger andNokleberg,
1996). Fragments of the continental-mgia arc include several metidlogenic belts hosting the kmko massive sulfide and related
deposlts (Nokleberg and others, 19974 b, c): (1) The h t i c mtslbgenk belt hosted in the Coklfoat &ram in Arctic Alaslut; (2)
Alaska Range and Yukon-Tanana Upland m4dogenic belt bwted io the Yukon-Taana tern iB central and atern Ahska; and
(3) the Frances Lake and Finlayson Lake metallqanics belt hted in the Yukon-Tanma tenme in the southem Yltlran Territory.
The Cyprus massive sulfde depwib in tbe KookmyShwap metallogenic belt are bated in Devonian M c volcanic
and associated metasedimentary rocks. The deposits and hasr oaumic sssemblges, together with SEDEX sulfide deposits and
thelr host rocks, occur in imbricard Lmst &to within other lssrremblages in the Kootenay tcmme. Them oceanic assemblages
and deposits, which are interpreted to have farmed in the back-(UY: of tbe Kootenay arc, and were su~ueocaIly structurally
emplaced within shelf and contiaenlal-mtwgin arc parts of h Korrtenay terrane during accretion of the outbwd.Slide Mountain
oceanic terrane in the Jurassic (Monger and NoUeberg. 1996; Nddeberg and others, 2000).
The Besshi Cu-Zn-Ag deposits in the Kmkn@hu%wrp metallogenic belt are hosted in Cm- tboleiitic metavolcanic
and associated rocks which const~tutes the older pert of he Kmtenay terrane. The Besshi Cu-Zn-Ag deposits in the Kootmy-
Shuswap metallogenic belt are herein interpreted as forming in a short-lived Cambrian contiaental-margin arc,
The Adams Plateau SEDEX Zn-PbAg deposits in the btenay-Shmmp metallogenic belt are hosted in Cambrim
metasedimentary rocks. The deposits ate mrrelated with similar SEDEX deposits m the Kooknay metidlogenie belt to the east,
and with deposits in the Anvil and Howards Pass metallogenic.belts to the north in the Sewn Besin of xhe norkn Canadian
Cordillera. All three metallogenic belts are interpreted as forming hm Pb- and Zn-rich fluids during rifibg, u o l kina1 ~
subsidence, local marine transgression, and related hydrothml activity along the passive conhmiffll margirt of the North
American Craton.
Metallogenic Belts Formed During
Middle Paleozoic Rifting of North Asian
Craton Margin
Khamna River Metallogenic Belt of
Carbonatite-Related Nb, Ta, and REE
Deposits (Belt KR) Southern Part of
Eastern Siberia
The Khamna River metalloggnic belt of carbonatite-relaud Nb. Ta, aad REE deposits [tables 3,4) wcm in the southem
part of eastern Siberia in the N~rlh Asim Cmton -gin (fig. 16; Verkhoyansk fold belt, unit NSW (Notdeberg and stbezs,
1994~). The belt strikes nortb-south, is about 300 krn long, and varies from 20 to 60 krn wide, The significant dcposits are at
Khamna and Garnoye Ozero (table 4) @&erg and others 1997% b, 1998). These deposits msbt of pyroohhte, arthiwr,
perovskite, and m~nozite which occur in halos adjacent to or around U i c igrmus rocks. The Khamna fiver metallogenic belt is
simllar to the Tomrnot River mcrallogrmlc Mt, described below, occurs in the paesive continental mmgh hdevka terrane of the
Kolyma-Omolon supertenme in the westun part of the Russian Northeast.