Geologic description
The Chitsia Mountain area is underlain by Middle Devonian to Early Mississippian Totatlanika Schist (Wilson and others, 1998). This formation consists of slightly metamorphosed volcanic sedimentary rocks, including various phyllites, silicified greenschist, and nonresistant greenschist tuffs. It is intruded by resistant porphyro-aphanitic rhyolite (Bundtzen and others, 1976). Regionally, the area contains a system of northeast-trending strike-slip and related conjugate faults associated with Cretaceous to Tertiary plutonic rocks and coeval or younger volcanic rocks (Clautice and others, 1993). The three occurrences consist of a quartz vein system trending N 55 E and dipping 55 degrees SE, hosted in the rhyolite. The quartz veins locally contain limonite and galena. A sulfide-bearing quartz vein sample was assayed by atomic absorption and contained 0.05 ounces Ag per ton, 0.01 ounces Au per ton, less than 0.01 percent Cu, 0.01 percent Pb, 0.02 percent Zn, less than 0.01 percent Mo, and less than 0.01 percent Sb. A stream-sediment sample collected near the rhyolite was assayed by atomic absorption and contained 0.03 ppm Au, 34 ppm Cu, 24 ppm Pb, 125 ppm Zn, and 1.10 ppm Ag (Bundtzen and others, 1976). These areas of base-metal vein mineralization in rhyolite are interpreted to have potential for large low-grade and smaller high-grade metallic deposits (Bundtzen and others, 1976). There are no indications of production. |
