Unnamed (north of Arrigetch Peaks) (ARDF #SP015) As, Cu, Sn, Zn

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.

References

MRDS Number	10308329
References Grybeck, D.J., and Nelson, S.W., 1981, Mineral deposit map of the Survey Pass quadrangle, Brooks Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1176-F, 1 sheet, scale 1:250,000. 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