Unnamed Occurrence (ARDF - HE110; upper Edgar Creek), Bonnifield Mining District, Denali Borough, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - HE110; upper Edgar Creek)	- not defined -
Bonnifield Mining District	Mining District
Denali Borough	Borough
Alaska	State
USA	Country

Location: This occurrence is at an elevation of about 5,500 feet, in the eastern headwaters of upper Edgar Creek, a tributary to the Yanert Fork River. The map site is in the NE1/4 of sec. 10, T. 15 S., R. 2 W., of the Fairbanks Meridian. The location is accurate to within 2000 feet. This is location 26 of Sherwood and others (1976).
Geology: The country rocks in the area of this occurrence are the Devonian Yanert Fork sequence, consisting mainly of siliceous mudstone, argillite, slate, phyllite, semischist, and impure quartzite. Thin interbeds of banded metachert and metavolcanic rocks are also present (Wilson and others, 1998). The bedded rocks are cut by Triassic(?) gabbroic sills and dikes. The occurrence consists of disseminations of chalcopyrite and possibly other sulfide minerals, in the metasedimentary rocks near a gabbro sill. Locally, the copper mineral(s) are oxidized to malachite. Samples contained 4,700 ppm copper and 0.4 ppm gold (Sherwood and others, 1976).
Workings: Surface samples only. Samples contained 4,700 ppm copper and 0.4 ppm gold (Sherwood and others, 1976).
Age: Possibly Triassic, assuming that the mineralization is related to the gabbro.

Commodities (Major) - Cu; (Minor) - Au
Development Status: No

Other Databases

Link to USGS - Alaska:	HE110

Other Regions, Features and Areas containing this locality

References