Twin Lakes West Occurrence, Bristol Bay Mining District, Lake and Peninsula Borough, Alaska, USAi

Regional Level Types
Twin Lakes West Occurrence	Occurrence
Bristol Bay Mining District	Mining District
Lake and Peninsula Borough	Borough
Alaska	State
USA	Country

Site is in Lake Clark National Park and Preserve.
Location: About 2.1 km north of the eastern arm of Twin Lakes on peak 5,280. The 1.3 km wide, oval-shaped occurrence extends approximately 7.3 km S-SE across Twin Lakes, terminating near peak 5,570. Corresponds with locality 11 of Nelson and others (1985) and locality 21 of MacKevett and Holloway (1977). Sec. 22, T. 7 N., R. 26 W., of the Seward Meridian. Longitude and latitude of occurrence is accurate within 1,200 m.
Geology: Mineralization occurs as fine-grained disseminations and hairline fracture fillings of pyrite and lesser chalcopyrite, sphalerite, and galena in silicified rhyolite and rhyolite-dacite volcanic rocks and breccias (Nelson and others, 1983). Resource Associates of Alaska (1976) considered the setting as a possible volcanic vent center. These rocks have undergone epidote and chlorite alteration, silicification, and lesser sericitization. The volcanic rocks have potassium-argon ages that range from 56.2 to 62.7 m.y. (Eakins and others, 1978).
Age: The volcanic rocks that host the mineralization have potassium-argon ages that range from 56.2 to 62.7 m.y. (Eakins and others, 1978).
Alteration: The volcanic rocks have undergone epidote and chlorite alteration, silicification, and lesser sericitization.
Production: No production
Reserves: No reserves

Commodities (Major) - Cu, Pb, Zn
Development Status: None
Deposit Model: Polymetallic vein ? (Cox and Singer, 1986; model 22c ?)

Other Databases

Link to USGS - Alaska:	LC017

Other Regions, Features and Areas containing this locality

References