Geochemical signatures around massive sulphide deposits in southern British Columbia, Canada

This paper demonstrates the application of geochemical exploration for sulphide mineralization in glaciated areas by a case history illustrating the discovery of Cu-Pb Zn-Ag-Au massive sulphide deposits in southern British Columbia, Canada. These deposits, hosted by Palaeozoic metasedimentary and metavolcanic rocks of the Kootenay Terrane, were first detected by weakly anomalous Cu and Au values in regional stream sediment samples and subsequently confirmed by more detailed stream and soil geochemical surveys, prospecting and diamond drilling. Till geochemistry is a very effective exploration method because there is a well developed dispersal plume of mineralized bedrock down-ice from the massive sulphide deposits. Elevated Au, Pb, Cu and As levels in till samples collected up to 8 km down-ice from the deposits are direct indicators for sulphide mineralization. Barium, Cr and Ni are pathfinders for distinguishing different types of sulphide mineralization. The relationship between the bedrock, stream sediment, stream water and till geochemistry is shown more clearly in a conceptual model. This model has a practical application to future exploration for massive sulphides in southern British Columbia by establishing criteria such as geochemical anomaly size and contrast for different sample media.