Key mineral assemblages help determine pressure, temperature and depth of emplacement for mineralized veins of the Keno Hill district, as well as for local Cretaceous pluton emplacement. New electron microprobe analyses are presented on samples collected in the field, enabling further characterization of the hydrothermal and plutonic regimes. Staurolite-garnet-albite-biotite schist along the margins of the Cretaceous Roop Lakes stock record contact metamorphic conditions, averaging 518°C and 3450 bar. To the west, hydrothermal veins of the Keno Hill district containing pyrite-pyrrhotite-sphalerite-arsenopyrite, indicate hydrothermal conditions of approximately 400°C and 1500 bar. Lithostatic conditions for the pluton, and likely hydrostatic conditions for the veins, are interpreted to indicate a similar depth of emplacement for the two systems, near 10-13 km below the surface.
