Unnamed (north of Coal Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag
Ore minerals chalcocite; malachite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-6
Latitude 63.1863
Longitude -146.9364
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 4,500 feet on the south side of the ridge north of Coal Creek. The occurrence is in the NE1/4 section 15, T. 20 S., R. 4 E., Fairbanks Meridian. It is an approximate location that may correspond to locality 4 in figure 4 of Cobb (1979 [OFR 79-238]).

Geologic setting

Geologic description

The rock at this site is the Nikolai Greenstone of Late Triassic age (Nokleberg and others, 1991). The occurrence is one of several copper in basalt occurrences reported by Smith and others (1973, 1975). Copper, accompanied by epidote and quartz, occurs in primary chalcocite and secondary malachite in vesicles, veinlets, and on fracture surfaces. The host rock is propylitized.
Geologic map unit (-146.938664122672, 63.1858573592053)
Mineral deposit model Basaltic (greenstone) Cu (Cox and Singer, 1986; model 23).
Mineral deposit model number 23
Age of mineralization Probably Cretaceous or early Tertiary (see MH060).
Alteration of deposit Propylitic alteration.

Production and reserves

Workings or exploration This occurrence was found during mapping and reconnaissance sampling (Smith and others, 1973, 1975).
Indication of production None