Extensions and Affiliates of the Yukon-tanana Terrane in Northern British Columbia

Kudz Ze Kayah (KZK) and Wolverine are volcanogenic massive sulphide deposits hosted by Early Mississippian meta-rhyolites, marine metasediientmy rocks and intermediate to mafic met&offs of the Yukon Tanana Terrane in the Finlayson Lake area, southern Yukon (Figure 1). This area became a focus of intense exploration in late 1994, following Cominco’s discovery of significant massive sulphides associated with metarhyolites in the ABM zone, at what later became their Kudz Ze Kayah project. Reserves at Kudz Ze Kayah now stand at 11.3 million tonnes of 6% Zn, 1% Cu, 1.3% Pb, 125 g/tonne Ag and 1.3 g Au. In 1996, reserves at Westmin-Atna Resources Wolverine deposit were 5.3 million tonnes of 1.8 g/tonne Au, 360 g/tonne Ag, 13% Zn, 1.4% Cu and 1.5% Pb; new discoveries in 1997 will upgrade this figure. Columbia Gold’s Fyre Lake deposit, located in the Finlayson Lake district 50 km south of Kudz Ze Kayah, contains a significant copper-cobalt-gold resource within a complex series of massive sulphide lenses enclosed by a mafic m&volcanic host (Blanchflower ef 01,. 1997). This project aims to pinpoint, within central northern B.C., stratigraphy favorable to the formation of Early Mississippian volcanogenic massive sulphide deposits similar to Kudz Ze Kayah, Wolverine, and (?)Fyre Lake. In 1996, six widely scattered target areas were mapped and evaluated for this potential (Nelson, 1997). In 1997 the focus was narrowed to two areas and systematic, detailed geological mapping was begun (Figure 2). Most of the work was done on the Big Salmon Complex in northwestern Jennings River (1040) and northeastern Atlin (104N) map areas, the direct strike continuation of Yukon Tanana rocks from the Teslin map area of southern Yukon into northern B.C. It is the subject of a companion paper (Mihalynuk ef al., this volume). This paper describes the results of preliminary mapping in the stmctumlly lower part of the Dorsey Termne in central Jennings River map area (1040). REGIONAL CORRELATIONS AND CONTEXT