| High grade Ag-Pb-Zn veins of the Keno Hill district, in central Yukon, occupy sinistral strike-slip faults which formed in association with a broad region of upright shear, overprinting an earlier thrust system. Faults, fractures and veins are lithologically restricted to the graphitic Keno Hill Quartzite unit of Mississippian age. Hydrothermal veining is continuous for 40 km, and is contemporaneous with the Mayo Lake Pluton (81 Ma). Zoning is characterized by quartz-feldspar veins near the pluton, carbonate-Ag-Pb-Zn veins further away, and peripheral deposits of epithermal character.;;In the mining district, fluid inclusions were studied from early quartz, and from later siderite which is intergrown with the principal ore assemblage of galena, sphalerite, and tetrahedrite. The dominant components of the fluids are H... |
