Lichen; Rush Prospect, Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Lichen; Rush Prospect	Prospect
Valdez Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

MAS/MIL number 20700053.
Location: This prospect is at an elevation of about 3,150 feet, about 6 miles west of the Susitna River and 4.0 miles southeast of the center of Coal Lake. The prospect is about 0.15 mile west of the center of sec. 2, T. 32 N., R. 11 E., Seward Meridian. The location is accurate to within 1/4 mile. This is locality 18 of Csejtey and Miller (1978).
Geology: This prospect is a stratabound copper deposit in Triassic(?) metavolcanic rocks. Veins and disseminated sulfides occur in a mafic, volcanic flow (Smith and others, 1975; Schmidt and others, 2002). The ore minerals are confined to a single flow, and consist of disseminations and veinlets of bornite, chalcopyrite, covellite, digenite, and malachite. Veinlets average less than 0.4 inches thick and contain quartz, feldspar, and epidote as well as sulfides. The mineralized zone is about 6 feet by 3,000 feet in size; it strikes N60W and dips nearly vertically. The host rock has undergone greenschist-grade regional metamorphism and is coated with secondary iron and copper minerals. Samples of mineralized rock contain up to 4.5 percent copper, 16 parts per million gold, and 68 parts per million silver (Smith and others, 1975). The prospect was explored in the 1970's by Cities Service Minerals using soil geochemical sampling, ground magnetic and EM surveys, and excavation of 2 trenches. Seraphim Engineering and Cities Service Minerals Company staked 145 claims in 1975-1976. The Amphitheater 1-25 claims were staked by Cominco American in 1988. As of January 1, 2000 a large block of state mining claims and prospecting sites covered the prospect (Northern Associates Inc., written commun., 2001).
Workings: The prospect was explored in the 1970's by Cities Service Minerals using soil geochemical sampling, ground magnetic and EM surveys, and excavation of 2 trenches. Seraphim Engineering and Cities Service Minerals Company staked 145 claims in 1975-1976. The Amphitheater 1-25 claims were staked by Cominco American in 1988. As of January 1, 2000 a large block of state mining claims and prospecting sites covered the prospect (Northern Associates Inc., written communication, 2001).
Age: Occurs in Triassic(?) metavolcanic rocks.
Alteration: The volcanic host rock is altered to chlorite and epidote and stained with secondary iron and copper minerals.

Commodities (Major) - Ag, Au, Cu
Development Status: None
Deposit Model: Basaltic copper (Cox and Singer, 1986; model 23)

Other Databases

Link to USGS - Alaska:	TK045

Other Regions, Features and Areas containing this locality

References