Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold; pyrite; 'sulfides'
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5465
Longitude -150.918
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Pittsburgh prospect (Cobb, 1980 [OFR 80-363]) is at an elevation of about 2700 feet near the head of a south-facing gulch east of Iron Gulch. It is about 0.3 mile north of the center of section 7, T. 16 S., R. 17 W., Fairbanks Meridian. The location is accurate within about 500 feet. The prospect is included in occurrence 41 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The area of the Pittsburgh prospect is underlain by schistose metafelsite of the Spruce Creek sequence (Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, fig. K-2; v. 2, occurrence 41). The deposit consists mainly of a mineralized quartz-calcite vein that probably is the continuation of the Pennsylvania vein (MM116). According to Davis (1923, p. 129): 'Although there is a gap of about 1000 feet... it is quite likely that this vein [Pennsylvania] is the same one that is exposed on the discovery cut of the Pittsburgh claim. The vein matter is quartz containing some pyrite and calcite, and free gold can be panned from samples taken along the outcrop.' When visited by Davis, the discovery cut on the Pittsburgh vein was partly sloughed, but vein material was still visible. He reported a 6- to 7-foot-thick quartz-calcite vein containing sulfides.
Apparently, little work has been on the Pittsburgh claim since its discovery. A rock sample collected close to the west end line of the claim contained 1050 ppm lead and 4 ppm silver (Hawley and Associates, 1978, sample 147). Thornsberry, McKee, and Salisbury (1984, v. 2) found several sloughed pits and fairly abundant quartz float on the claim.
Geologic map unit (-150.920286264714, 63.5459943909179)
Mineral deposit model Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36c
Age of mineralization The deposit is assumed to be Eocene (see record MM091).

Production and reserves

Workings or exploration The property was developed by pits and shallow shafts in 1922 or earlier. The claim has been inactive for many years.
Indication of production Undetermined

Additional comments

The prospect is in Denali National Park and Preserve.