Unnamed (north of Arrigetch Peaks)

Occurrence, Inactive

Commodities and mineralogy

Main commodities As; Cu; Sn; Zn
Other commodities Bi
Ore minerals arsenopyrite; chalcopyrite; magnetite; pyrite; pyrrhotite
Gangue minerals calc-silicates

Geographic location

Quadrangle map, 1:250,000-scale SP
Quadrangle map, 1:63,360-scale B-3
Latitude 67.4499
Longitude -154.1653
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is an elevation of about 3,700 feet near the head of an unnamed creek 3 miles northeast of the Arrigetch Peaks. It is near the southeast corner of section 32, T. 24 N., R. 22 E., The site corresponds to locality 32 of Grybeck and Nelson (1981) and area 1 of the SP2 site of Kurtak and others (2002).

Geologic setting

Geologic description

This occurrence consists of selected float samples of iron-stained Paleozoic schist and skarn. The source of the float probably is a contact-metamorphic zone adjacent to Devonian granite that crops out to the south. Selected samples contained up to 5,000 parts per million (ppm) arsenic, 20 ppm bismuth, and 1000 ppm tin (Grybeck and Nelson, 1981). This occurrence probably is similar in origin to other Devonian contact-metamorphic deposits in nearby areas of the Brooks Range (Newberry and others, 1986). Kurtak and others (2002) collected several samples in the vicinity, notably of magnetite-calc-silicate ribbon rock, with pyrite, chalcopyrite, pyrrhotite, and arsenopyrite. . Samples contained up to 4,492 ppm copper, 4,052 ppm tin, and 859 ppm bismuth, and 7,782 ppm zinc.
Geologic map unit (-154.168104618566, 67.4494082181595)
Mineral deposit model Skarn (Cox and Singer, 1986; model 14b).
Mineral deposit model number 14b
Age of mineralization Probably related to nearby Devonian granite.
Alteration of deposit Calc-silicate minerals in skarn and related contact metamorphic rocks adjacent to a Devonian granite.

Production and reserves

Workings or exploration The site was briefly visited and sampled during regional geologic mapping by the USGS in the late 1970s and visited and sampled by the Bureau of Land Management in about 2000.
Indication of production None
Reserve estimates None.
Production notes None.

Additional comments

Located in the heart of a notable scenic part of the Gates of the Arctic National Park.


MRDS Number 10308329


Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Maclean, E.A., 2002, Mineral investigations in the Koyukuk mining district, northern Alaska: Final Report: U.S. Bureau of Land Management Technical Report 50, 2 vols., 845 p.
Newberry, R.J., Dillon, J.T., and Adams, D.D., 1986, Regionally metamorphosed calc-silicate-hosted deposits of the Brooks Range, northern Alaska: Economic Geology, v. 81, p. 1728-1752.
Reporters S.W. Nelson (Anchorage, Alaska); D.J. Grybeck (Contractor, USGS)
Last report date 2/1/2011