Unnamed (ridge northeast of Brooker Mountain)

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag; Sb
Other commodities As; Au; Cu; Pb; Zn
Ore minerals arsenopyrite; galena; pyrite; scorodite; sphalerite; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-3
Latitude 63.5115
Longitude -151.0403
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of about 3100 feet on the southeast- trending ridge about midway between Brooker Mountain and Alpha Ridge. It is in the SE1/4 section 21, T. 16 S., R. 18 W., Fairbanks Meridian. The location is accurate within 500 feet. The prospect corresponds to number 4 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The country rock at this prospect is feldspar-quartz-mica schist of the Birch Creek Schist (Bundtzen, 1981). Although the mineral deposit is not exposed, the distribution of float in relation to old pits and topography indicates that the deposit is a vein which strikes about EW and dips at a moderate or shallow angle to the south (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 4). A selected sample of sulfide-rich material in a pit assayed 144 ounces of silver per ton, 18 percent arsenic, and 45 percent antimony. It also contained 0.365 percent copper, 8.4 percent lead, and 3.75 percent zinc (Thornsberry, McKee, and Salisbury, 1984, v. 2). Some of the material contains about 50 percent stibnite. The high arsenic value indicates that arsenopyrite or its oxidation product scorodite is present.
Geologic map unit (-151.042585234926, 63.5109909331408)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization The deposit is assumed to be Eocene (see record MM091).

Production and reserves

Workings or exploration The vein has been explored by several shallow pits of unknown date.
Indication of production Undetermined

Additional comments

The prospect is in Denali National Park and Preserve.

References