Unnamed (west of the Middle Fork Chandalar River)

Prospect, Inactive

Commodities and mineralogy

Main commodities Pb; Zn
Other commodities Ag; Cu
Ore minerals chalcopyrite; galena; sphalerite; tetrahedrite
Gangue minerals barite; quartz

Geographic location

Quadrangle map, 1:250,000-scale PS
Quadrangle map, 1:63,360-scale A-2
Latitude 68.03
Longitude -147.87
Nearby scientific data Find additional scientific data near this location
Location and accuracy Site is at approximately 3,850 ft., about 4 1/2 miles west of the Middle Fork Chandalar River and about 8 miles south-southwest of the confluence of Beaucoup Creek and Middle Fork Chandalar River (west-center sec. 25, T. 16 S., R. 18 E., of the Umiat Meridian). The site corresponds to sample No. 76 ARR 47 shown in Detra (1977, fig. 1). Location accurate within 1/4-mile radius.

Geologic setting

Geologic description

Visible sphalerite and galena occur in a Cu-stained and quartz-veined chert (Menzie and others, 1985). The occurrence is at the upper contact zone of Devonian - Silurian(?) Skajit Limestone with overlying shales, sandstones and conglomerates of the Devonian Hunt Fork Shale and Beaucoup Formation. The chert occurs locally along this contact. The upper contact of the Skajit in this location is an unconformity that has been interpreted as a paleokarst surface. Analysis of a sample of the mineralization from this occurrence returned values of 2 percent Pb, 0.5 to 1 percent Zn, [more than] 0.5 percent Ba and 30 ppm Ag (Detra, 1977).
Geologic map unit (-147.872777263793, 68.0296413023476)
Mineral deposit model Mississippi Valley Zn-Pb? (Cox and Singer, 1986; model 32a?).
Mineral deposit model number 32a?

Production and reserves

Workings or exploration One block of 15 lode claims staked by RAA in 1977. Semi-quantitative spectrographic data from a rock sample (sample number 76 ARR 47) from the site gave the following values: Ag (30 ppm), Ba (greater than 5,000 ppm), Cd (70 ppm), Cu (1,000 ppm), Pb (20,000 ppm), Sb (300 ppm), Zn (10,000 ppm). Zn by wet chemical analysis - 5,000 ppm (Detra, 1977, table 1).
Indication of production None

Additional comments

See also locations PS006 and PS007. Site is in an area of potential carbonate-hosted lead-zinc deposits (Menzie and others, 1985).

References