In the Emperor mine area, widespread propylitic alteration was followed by limited K‐silicate alteration and mineralization within and along vein edges. The propylitic assemblage is characterized by chlorite, ankerite, magnetite and pyrite. The K‐silicate assemblage includes sericite, rare chlorite, quartz, K‐feldspar and pyrite. The propylitic rocks are depleted in Si, Na, and Mg, have minor increases in K, and have substantial additions of CO2. The K‐silicate rocks are depleted in Fe, Al, Na, Ca and Mg, and enriched in Si, K and CO2.