Mineralization and alteration at the Red Chris Cu-Au porphyry deposit, British Columbia, Canada

The Red Chris porphyry Cu-Au deposit, located in the northern Stikine Terrane of the Canadian Cordillera, contains high grade mineralization to depths of >1000 m. Mineralization at Red Chris is comprised of disseminated and fracture filling chalcopyrite and bornite within quartz veins and stockworks. Pyrite forms a halo around the chalcopyrite +/- bornite core. Alteration includes a high temperature (K-silicate) core of K-feldspar, secondary biotite, magnetite and anhydrite veinlets which have been intensely overprinted by lower temperature illite, kaolinite and lesser muscovite. In the East zone, the K-silicate zone dominates below 600-1000 m depth while the intense illite overprint dominates at shallower levels. Kaolinite alteration is concentrated in the upper 250 m. The presence of Mite and kaolinite as the dominant clay alteration minerals indicates a lower temperature fluid regime at Red Chris compared to classic 'phyllic' or muscovite-bearing alteration overprints.