Unnamed (between Sirr Creek and Wild Lake)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Sb
Other commodities Pb; Zn
Ore minerals chalcopyrite; galena; malachite; pyrite; tetrahedrite
Gangue minerals ankerite; calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale WI
Quadrangle map, 1:63,360-scale C-4
Latitude 67.5217
Longitude -151.5889
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is located on a ridge between Sirr Creek and Wild Lake, about 1.6 miles north of the mouth of Seward Creek on Wild Lake. It is about 0.4 mile south-southwest of the center of section 9, T. 31 N,, R. 18 W. The occurrence is the site of sample 128 of Chipp (1972). Several other samples were collected for about 1.5 miles up the ridge to the north by Chipp (1972), and Kurtak and others (2002) The location is accurate.

Geologic setting

Geologic description

This occurrence consists of numerous thin quartz veins and lenses in Middle to Lower Devonian chlorite and sericite schist (Dillon and others, 1986). Most are barren quartz although some also contain ankerite(?). Over an area about 200 by 300 feet in size, small amounts of tetrahedrite(?), chalcopyrite, galena, malachite, and pyrite are scattered through the quartz (Chipp, 1972; Kurtak and others, 2002). One sample of altered calcareous schist with vein quartz and unspecified sulfides contains 0.52 parts per million (ppm) gold, 31 ppm silver, 1 percent antimony, 9,700 ppm copper, 2,400 ppm lead, and 1,000 ppm zinc (Chipp, 1972; sample 128).
Geologic map unit (-151.591654214304, 67.5212485656802)
Mineral deposit model Scattered, thin quartz lenses and veins with rare, scattered base and precious-metal minerals.
Age of mineralization Unclear other than the veins and lenses are probably younger than the Devonian host rocks.
Alteration of deposit Chipp (1972) and Dillon and others (1981) describe some of the samples as altered calcareous-schist, but did not describe the alteration.

Production and reserves

Workings or exploration Briefly examined and sampled by the Alaska Division of Geological and Geophysical Surveys (Chip, 1972, Dillon and others, 1981) and the Bureau of Land Management (Kurtak and others, 2002).
Indication of production None
Reserve estimates None.
Production notes None.

References

MRDS Number A011935

References

Reporters J.M. Britton (Anchorage); D.J. Grybeck (Contractor, USGS)
Last report date 2/1/2011