Economic Geology STRATABOUND BASE METAL DEPOSITS OF THE BARKERVILLE SUBTERRANE, CENTRAL BRITISH COLUMBIA (093Amw)

INTRODUCTION The Barketille subterrane is part of the peri-cratonic Kootenay termne, deposited along the western edge of ancestral North America. The Kooteoay temme, and possible correlative rocks of northern British Columbia and Yukon, contain numc~ous volcanogenic massive solphide deposits, concentrated largely in EoCambrian to Early Cambrian and Middle Devonian to Early Mississippian times. These periods represent contrasting tectonic regimes along the continental margin, with distinct volcanic assemblages and characteristic massive solphide deposits. Tholeiitic and alkalic matic volcaoism in latest Precambrian through early Paleozic time records episodic extensional tectonics along the rifted, western margin of North America. Matic volcanics occur locally in the EoCambrian part of the Hamill Group, as Unit EBG in the Eagle Bay Assemblage and in the basal part of the Index Formation in the Goldstream area north of Revelstoke. A number of Cu-Zn Besshi-type deposits of the Goldstmm camp are the best examples of volcanogenic massive sulphides in these mafic volcmidmetasedimentary successions. Bimodal arc volcanism occured along the preserved western margin of the Kootenay terrane in middle to late Paleozoic time, in response to eastward subduction of a paleopacific ocean Within the Eagle Bay Assemblage, this volcanism is recorded as thick accumulations of II&C and felsic pymclastic rocks. In the Omineca Mountains in northern British Columbia, the Gilliland totT records similar volcanism (Ferri, 1997). Rhyolitic and rhycdacitic tot% of Unit EBA of the Eagle Bay Assemblage contain numerous small, polymetallic massive sulphide deposits. The objective of this study is to evaluate the potential for massive sulphide mineralization in the Barketille subtemme. This paper describes and classfies a number of known mineral occurrences and attempts to correlate stratigraphic packages in the Barkewille with other parts of the Kootenay terrane. REGIONAL GEOLOGY The Barkerville-Likely area is underlain by three fault-bounded geological termnes (Struik, 1988). The Barketille subterrane is separated from more inboard rocks of the Car&o subtemme by the west-verging Pleasant Valley thrust fault. The oceanic Slide Mountain temne has been stmctorally emplaced along the western margin of the Barkeaville subtemme, carried on the cast-verging Eureka Thmst fault (Figure 1). It also stmctorally overlaps the Barketille and Car&w terraoes along the Pundata thrust (Stmik, op. cif.). Rocks in these terranes have been polydeformed and metamorphosed, possibly as early as middle Paleozoic time (Sutherland Brown, 1963) but certainly during the package of rocks is dominated by distal, tine grained siliciclastics with lasser carbonate and volcanics. It has been subdivided into …