PMRGX-3

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Cu; Mo; Pb; Sb; Sn; Zn
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale PM
Quadrangle map, 1:63,360-scale A-3
Latitude 55.17
Longitude -160.669
Nearby scientific data Find additional scientific data near this location
Location and accuracy The map site of this occurrence is on Unga Island on the east shore of outer Acheredin Bay, about 1.9 miles south of the lagoon at the head of the bay (Christie, 1974, color anomaly 80; Wilson and others, 1988, locality 85). It is referred to as PMRGX-3 (Smoker) in Wilson and others (1988). The location is accurate to within 1,200 feet.

Geologic setting

Geologic description

This occurrence consists of a 1- by 2-mile color anomaly (Christie, 1974, color anomaly 80). At this site, Christie noted 6-inch to 3-foot-thick 'beds' of intensely argillized volcanic rock containing as much as 20 percent pyrite. The average pyrite content is 2 to 5 percent. A fractured diorite dike containing disseminated pyrite also crops out in the area. Two rock samples collected by Christie in 1974 contained as much as 0.01 ppm gold, 2.1 ppm silver, 98 ppm copper, 49 ppm zinc, and 1.6 ppm molybdenum. The country rocks are mapped as Eocene to Oligocene Popof volcanic rocks (Wilson and others, 1995).
Six rock samples collected by the U.S. Geological Survey in the mid-1980s were reported to be anomalous in antimony, copper, gold, lead, silver, and tin (Wilson and others, 1988).
Geologic map unit (-160.671075049768, 55.1691613976978)
Age of mineralization Eocene or younger.
Alteration of deposit Extensive intense clay-pyrite alteration (acid sulfate?).

Production and reserves

Workings or exploration An Aleut-Quintana-Duval joint venture carried out brief reconnaissance mapping and sampling in 1974 (Christie, 1974). Only minor amounts of base and precious metals were found. UNC Teton Exploration Drilling Company geologists examined the site during the period 1979-1981. They called it a 'smoker-type' occurrence, but found little of interest. Samples collected by the U.S. Geological Survey in the mid-1980s were reported to be anomalous in antimony, copper, gold, lead, silver, and tin (Wilson and others, 1988).
Indication of production None

Additional comments

The site is located on land patented by, or interim-conveyed to, the Aleut Corporation.

References