UBC Theses and Dissertations
Geology and lithogeochemistry of the cirque stratiform sediment-hosted Ba-Zn-Pb-Ag deposit Northeastern British Columbia Gorzynski, George Arthur
The Cirque deposit is one of several Devono-Mississippian stratiform sediment-hosted Ba-Pb-Zn-Ag deposits in the Akie Zn-Pb district of northeastern British Columbia. It has drill indicated reserves of 32.2 million tonnes grading 7.9% Zn, 2.1% Pb, and 47.7 g/tonne Ag. The "ore" zone is a syngenetic exhalite deposit. Its deposition, however, was but one of many wide-ranging "ore"-related events that dominated sedimentation in the shale basin. These "ore"-related events include exhalative activity, influxes of turbidites and increased organic productivity. Many details of the "ore"-related events can be deduced from field observations and bulk lithogeochemical data. In this study 271 samples representing over 700 m of drillcore were analysed for up to 33 elements. These lithogeochemical data were investigated using a standardization procedure in which analyses were ratioed to the abundances of the relatively immobile detrital components, alumina and zirconium. After this transformation, anomalous abundances of "ore" constituents (Ba, Fe, Zn, Pb, Ag and S) and many other chemical components, were identified in the host rocks beyond the immediate vicinity of the "ore" zone. This procedure also facilitated an estimate of provenance for the host rocks and their relative rates of sedimentation. Geochemical trends are also evident within the "ore" zone. Ba:Sr ratio trends mimic Pb:Zn ratio trends and may be a useful tool in the study and exploration of other stratiform barite deposits. They delineate zoning patterns and may act as a guide to exhalative vent areas which may be of economic interest.
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