Unnamed (north of upper South Fork, Otter Creek) (ARDF #ID062) Cu

Unnamed (north of upper South Fork, Otter Creek)

Prospect, Inactive

Commodities and mineralogy

Main commodities	Cu
Other commodities	As; Hg
Ore minerals	iron oxide
Gangue minerals	carbonate minerals; quartz

Geographic location

Quadrangle map, 1:250,000-scale	ID
Quadrangle map, 1:63,360-scale	C-4
Latitude	62.54873
Longitude	-157.60098
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This prospect is at an elevation of about 1,700 feet in a saddle on an irregular-shaped ridge between the head of the Dishna River and the head of the North Fork of Otter Creek. The prospect is about 1.1 mile north of hill 1861 and 1.4 mile west of hill 2208 and near the center of the N1/2 section 3, T. 28 N., R. 45 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description This prospect is in an area of pronounced gossan development associated with silica-carbonate-altered mafic dikes that cut sandstone of the Upper Cretaceous, Kuskokwim Group (Miller and Bundtzen, 1994; Miller, Bundtzen, and Gray, 2005). Several prospect pits explored three pods of iron oxide gossan. The total length of gossan is about 160 feet. Grab samples of gossan contain up to 340 parts per billion (ppb) mercury, 60 parts per million (ppm) arsenic, 100 ppm copper, and a trace of silver (McGimsey and others, 1988).
Geologic map unit	(-157.603363800168, 62.5480486478993)
Alteration of deposit	Silica-carbonate alteration of mafic dikes.

Production and reserves

Workings or exploration	Surface samples were collected by the Alaska Division of Geological and Geophysical Surveys and the U.S. Geological Survey in 1986 (McGimsey and others, 1988).
Indication of production	None

References

References McGimsey, R.G., Miller, M.L., and Arbogast, B.F., 1988, Paper version of analytical results, and sample locality map for rock samples from the Iditarod quadrangle, Alaska: U.S. Geological Survey Open-File Report 88-421-A, 110 p., 1 sheet, scale 1:250,000. Miller, M.L., and Bundtzen, T.K., 1994, Generalized geologic map of the Iditarod quadrangle, Alaska showing potassium-argon, major oxide, trace element, fossil, paleocurrent, and archeological sample localities: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-A, 48 pages; 1 sheet, scale 1:250,000. Miller, M.L., Bundtzen, T.K., and Gray, J.E., 2005, Mineral resource assessment of the Iditarod quadrangle, west-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-B, scale 1:250,000, pamphlet.
Reporters	T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); and C.C. Hawley (Hawley Resource Group)
Last report date	5/19/2003