| Comments |
Area is underlain by highly altered, border-phase rocks of the Pennsylvanian- to Permian-age Ahtell Creek quartz monzonite pluton; the pluton intrudes the Pennsylvanian- to Permian-age Tetelna Formation (mainly volcanic rocks). Both the Ahtell pluton and the Tetelna Formation are cut by dikes and irregular bodies of a mid-Jurassic-age complex that varies from diorite to quartz diorite; porphyry mineralization occurs mainly in the diorite complex and adjacent hornfels. Potassic alteration with potassium feldspar, biotite, and magnetite is nearest the mineralization; succeeded by a shell of sodium-calcium alteration with albite, actinolite, and magnetite; followed by an outermost shell of propylitic alteration with pyrite. Explored extensively since the discovery of placer deposits in the area in 1934; geologic mapping, sampling, and geochemical surveys, and aerial geophysical survey in 2006; 3 holes drilled in 2010 intersected extensive altered and mineralized rock. No reserves. |
