Unnamed (north side of Spruce Peak and upper Glen Creek)

Prospects, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; As; Pb; Zn
Ore minerals arsenopyrite; galena; pyrite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5834
Longitude -150.7046
Nearby scientific data Find additional scientific data near this location
Location and accuracy This record describes two prospects. One, at the coordinates for this record, is on the northwest flank of Spruce Peak at an elevation of about 4350 feet. This prospect corresponds to occurrence 86 of Thornsberry, McKee, and Salisbury (1984) and is accurate within 500 feet. The other prospect is in upper Glen Creek. It corresponds to occurrence 79 of Thornsberry, McKee, and Salisbury.

Geologic setting

Geologic description

The two prospects described in this record are geologically similar. Both are in massive metafelsite of the lower Paleozoic Spruce Creek sequence, and feature disseminations and stratiform, semi-massive aggregates, of pyrite (Bundtzen, 1981). At the prospect on the northwest flank of Spruce Peak, the pyrite is accompanied by small amounts of arsenopyrite, sphalerite, and probably galena. The prospect in upper Glen Creek contains only pyrite.
A representative sample of the deposit northwest of Spruce Peak assayed 8.2 ppm gold, 12 ppm silver, 2600 ppm arsenic, 1850 ppm lead, 1500 ppm zinc, and 26 ppm tungsten (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 86). Soils near the prospect contain 0.1 to 0.95 ppm gold and 0.2 to 1.2 ppm silver (Hawley and Associates, 1978, samples 264, 265, fig. 4.1-A(1)).
At the prospect in upper Glen Creek, layers of metafelsite as much as 0.5 foot thick contain up to 20 percent pyrite. Samples assay up to 270 ppm arsenic and 14 ppm antimony, background values of copper, lead, and zinc, and no gold or silver (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 79).
Geologic map unit (-150.706884326099, 63.5828994587492)
Mineral deposit model Stratabound massive sulfide deposit in metafelsite (Cox and Singer, 1986; model 28a?).
Mineral deposit model number 28a?
Age of mineralization These stratabound deposits might be early Paleozoic, the protolith age of the Spruce Creek sequence.

Production and reserves

Workings or exploration The deposits were explored by small pits.
Indication of production None

Additional comments

The prospects are in Denali National Park and Preserve.

References