Unnamed (southwest edge of Buckstock Mountains)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Bi
Ore minerals pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SM
Quadrangle map, 1:63,360-scale A-8
Latitude 61.15326
Longitude -158.85205
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the summit of a prominent, northeast-trending ridge at the head of two, north-flowing, unnamed tributaries of the Aniak River. The occurrence is at an elevation of about 1,800 feet, about 0.7 mile southwest of hill 2303 near the southwest corner of section 3, T. 12 N., R. 54 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence is a vuggy quartz vein that cuts sedimentary rocks of the Mesozoic Gemuk Group, adjacent to a large, sericitized, felsic dike (Cady and others, 1955; T.K. Bundtzen, unpublished field data, 1999). The dike strikes northeast and dips about 40N; the quartz vein parallels the dike. One grab sample of the quartz vein contained 63 parts per billion (ppb) gold, 4,000 ppb silver, and 21 parts per million (ppm) bismuth. A sample of gossan collected in a dike swarm to the north of the this occurrence contained 188 ppm arsenic, 338 ppm copper, and 230 ppm zinc (D. Bradley, unpublished analytical data, 1999).
Geologic map unit (-158.854375823213, 61.1525466578368)
Mineral deposit model Polymetallic vein? (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c?
Age of mineralization Unknown. Miller and others (2002) report a U-Pb age of 59.2 Ma from the Buckstock pluton.
Alteration of deposit Sericite in felsic dike.

Production and reserves

Workings or exploration The U.S. Geological Survey investigated the occurrence in 1999.
Indication of production None



Reporters T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.) and M.L. Miller (U.S. Geological Survey)
Last report date 5/10/2003