Geochemistry of shales as vectors to ore deposits : CAMIRO Project 08E04

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A wide range of economic ore deposit types, including base metals, gold, and uranium, are hosted by or spatially associated with sulphide-bearing, carbonaceous shales or argillites. Carbonaceous shales and argillites are readily identified in airborne electromagnetic surveys and are commonly drilled as potential hosts for volcanogenic massive sulphide (VMS) and sedimentary exhalative (SEDEX) ore deposits. They are also important hosts for orogenic gold, uranium, sediment-hosted copper, and deposits enriched in other metals (e.g., Ni, PGE). In some cases black shales were a reductant trap for metals; in others, they are important lithogeochemical markers of ore-forming events or potential source rocks for metals. However, the role of carbonaceous shales in ore formation remains poorly understood and there are few well-established indicators of ore potential in these rocks in different geological environments. A new international program of research on the lithogeochemistry of shales in relation to different ore deposit types is being initiated with the support of 5 mining companies (Barrick Gold, HudBay Minerals, Newmont, Teck, Ur Energy) as Project 08E04 of the Canadian Mineral Industry Research Organization (CAMIRO). The principal objectives of the project are (i) to improve the current understanding of metal enrichment in shales and argillites in ancient volcanosedimentary basins and in orogenic belts, (ii) to assess the role of carbonaceous sediments as both metal sources and metal traps, during sedimentation and during post-burial metallogenesis (e.g., in orogenic gold deposits), and (iii) to develop new mineralogical, geochemical, and isotopic tools to discriminate between potentially mineralized and unmineralized shales in a variety of ore-forming environments. Five graduate students (3 in Canada, 2 in the U.S. and Australia) will contribute to the project through case studies of base metal deposits, gold deposits, and uranium deposits. Students will gain experience in field work, laboratory analysis, industry interaction, and interpretation and preparation of research publications. Exploration technology developed during the project will be transferred directly to mining companies through the collaborative partnership.