Textural and mineralogical characterization of a Ni-Zn-rich black shale occurrence at the Akie property, Kechika Trough, northern British Columbia, and comparison with examples from Yukon (original) (raw)

Hyper-enriched black shales (HEBS) that are enriched in Ni, Zn, Mo, and other elements occur within the Devonian strata of Yukon over 100s to 1000s km2. The mineralization is typically up to several tens of centimetres thick. Recently, during exploration for SEDEX deposits, mineralization that is potentially analogous (and time-stratigraphically equivalent) to HEBS mineralization in Yukon was discovered in the Kechika Trough of northeastern British Columbia. Here, about 3 to 20 m stratigraphically below the SEDEX mineralization of the Cardiac Creek deposit, an approximately 2 to 20 cm thick stratiform horizon hosts sphalerite, chalcopyrite, millerite, gersdorffite, clausthalite, pentlandite and pyrite within Devonian black, carbonaceous shale. This mineralization is strikingly similar in broad stratigraphic age, metal enrichments, textures and mineralogy to HEBS localities in Yukon. Based on these similarities, this mineralization likely was formed at a discrete time interval, over a wide area (likely 1000s km2) within the Selwyn Basin and the adjacent carbonate platform. This has implications for any genetic and exploration model(s) for this style of mineralization.