Unnamed Occurrence (ARDF - MH049; between Clearwater Creek and West Fork Maclaren River), Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH049; between Clearwater Creek and West Fork Maclaren River)	- not defined -
Valdez Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

Location: This occurrence is at an elevation of about 5,500 feet about midway between Clearwater Creek and the West Fork Maclaren River. The map site is near the top of the ridge about 0.4 mile west-northwest of VABM Little in section 15, T. 20 S., R. 5 E., Fairbanks Meridian. The occurrence corresponds to locality 8 in figure 4 of Cobb (1979 [OFR 79-238]) and to locality 15 in table 2 of Nokleberg and others (1991). The location is probably accurate within one-third mile.
Geology: The country rock at this occurrence is basalt of the Nikolai Greenstone of Late Triassic age (Nokleberg and others, 1991). The mineral deposit is a vein in propylitically altered greenstone. A quartz-epidote vein in an approximately 9-foot-wide shear zone contains bornite, chalcocite, and malachite. Sample 79IL031A of vein material assayed 2.4 percent copper, 15 parts per million (ppm) silver, and 0.1 ppm gold (Nokleberg and others, 1991, locality 15).
Workings: The occurrence was probably first reported in the early 1970's (Smith and others, 1973, 1975); it was revisited and sampled by the U.S. Geological Survey in the 1980's (Nokleberg and others, 1991).
Age: The copper deposits are younger than a pre-Late Jurassic period of folding of basaltic host series (Stout, 1976, p. 30-31). They are probably Cretaceous or early Tertiary (see MH060).
Alteration: Propylitic alteration of basalt.

Commodities (Major) - Ag, Cu; (Minor) - Au
Development Status: None
Deposit Model: Copper-bearing vein in weakly cupriferous greenstone. Basaltic Cu (Cox and Sin

Other Databases

Link to USGS - Alaska:	MH049

Other Regions, Features and Areas containing this locality

References