Unnamed (on Kupreanof Peninsula)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag; Zn

Geographic location

Quadrangle map, 1:250,000-scale SB
Quadrangle map, 1:63,360-scale D-5
Latitude 55.79
Longitude -159.57
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrrence is on the Kupreanof Peninsula, near the head of Osterback Creek (MacKevett and Holloway, 1977, locality 6; Wilson and others, 1988, locality 6). The map site is at an elevation of 1,500 feet, 0.2 mile southeast of the center of sec. 1, T. 51 S., R. 67 W., of the Seward Meridian. The location is accurate to within 2 miles.

Geologic setting

Geologic description

There are contradictory descriptions of the geology of the area of this occurrence. MacKevett and Holloway (1977) and Hollister (1978) reported several altered zones in Tertiary bedded rocks, in or near Tertiary granitic plutons. Hollister (1978) classified the plutons as quartz diorite and reported a color anomaly marking areas of stockwork mineralization accompanied by phyllic, argillic, and propylitic alteration. In the mid-1980s the U.S. Geological Survey mapped the rocks in the area as Eocene to Oligocene Meshik Formation, and did not report any granitic rocks (Wilson and others, 1995). They collected few samples that were reported to be anomalous in copper, silver, and zinc (Wilson and others, 1988).
Geologic map unit (-159.572088580016, 55.7891958724572)
Age of mineralization Tertiary.
Alteration of deposit Hollister (1978) reported phyllic, propylitic, and argillic alteration in an area marked by a large color anomaly.

Production and reserves

Workings or exploration The U.S. Geological Survey mapped and sampled this area in the mid-1980s. Samples 83AYb590-594 and 83AWs78-81 were reported to be anomalous in copper, zinc, and silver (Wilson and others, 1988).
Indication of production None

Additional comments

This occurrence is in the Alaska Peninsula National Wildlife Refuge, near the boundary of land selected by the Bristol Bay Native Corporation.