Unnamed (west of lower Eureka Glacier)

Occurrence, Active

Commodities and mineralogy

Main commodities Cr
Ore minerals chromite
Gangue minerals olivine; serpentine

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-5
Latitude 63.3155
Longitude -146.4291
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 6,500 feet on peak 6580, about 2 miles west of the toe of Eureka Glacier, near the north end of the boundary between sections 32 and 33, T. 18 S., R.7 E., Fairbanks Meridian. The occurrence corresponds to locality 37 in table 2 of Nokleberg and others (1991).

Geologic setting

Geologic description

This occurrence is in an Upper Triassic mafic intrusive complex (Nokleberg and others, 1991). Rose (1966 [ADMM GR 20, figure 3]) mapped the complex as diorite, quartz diorite, and gabbro. The occurrence consists of chromite disseminated in a serpentinized olivine cumulate inclusion in metagabbro. Sample 79NK242B contained more than 0.5 percent chromium (Nokleberg and others, 1991).
Geologic map unit (-146.431366697806, 63.3150735652461)
Mineral deposit model Disseminated chromite in mafic-ultramafic rock.
Age of mineralization Late Triassic, the age of the ultramafic inclusion.
Alteration of deposit The olivine cumulate inclusion is serpentinized.

Production and reserves

Workings or exploration This occurrence was discovered during geologic mapping (Nokleberg and others, 1991). It is on active MAN Resources claims (W.T. Ellis, unpublished field notes, 2001).
Indication of production None