Unnamed (southeast foot of Sugarloaf Mountain)

Occurrence, Active

Commodities and mineralogy

Main commodities Fe
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-4
Latitude 63.1346
Longitude -145.9128
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of 3,950 feet on the southeast flank of Sugarloaf Mountain. It is at the center of SW1/4 section 31, T. 20 S., R. 10 E., Fairbanks Meridian. It corresponds to locality 4 of Rose (1966 [ADMM GR 19]).

Geologic setting

Geologic description

Permian black shale and calcareous black shale at this location contain abundant pyrite, including lenses of almost massive pyrite as much as one-half inch thick (Rose, 1966 [ADMM GR 19]). Analysis of a chip sample showed only 35 parts per million (ppm) copper, 105 ppm zinc, 20 ppm lead, and 9 ppm molybdenum (Rose, 1966 [GR 19]). L.D. Hulbert (oral communication, 2001) suggested that the mineralization could be magmatic, related to the emplacement of high-level metal-depleted gabbroic sills that may be feeders to the Nikolai Greenstone of Late Triassic age.
Geologic map unit (-145.91504231924, 63.1341772235514)
Mineral deposit model Shale-hosted sulfide.
Age of mineralization Permian or Late Triassic.

Production and reserves

Workings or exploration
Lithochemical sampling by MAN Resources indicates extreme metal depletion.
The occurrence is on active claims of MAN Resources.
Indication of production None



Reporters W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)
Last report date 6/17/2002