1. Mineral Resources
  2. Online Spatial Data
  3. Alaska Resource Data File (ARDF)

Unnamed (near Siwash Creek)

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Cu
Ore minerals azurite; copper sulfides; malachite

Geographic location

Quadrangle map, 1:250,000-scale CH
Quadrangle map, 1:63,360-scale A-5
Latitude 67.1198
Longitude -149.4035
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence is about 4.1 miles east of the junction of Siwash Creek and Mosquito Fork, at an elevation of about 2,300 feet. It is about 0.3 mile southwest of the center of section 3, T. 27 N., R. 8 W.. The location is accurate to within 1 mile.

Geologic setting

Geologic description

This occurrence was originally described as copper sulfides and copper stains in a small body of chert in Devonian(?) volcanic rocks (Brosgé and Reiser, 1964; DeYoung, 1978). Kurtak and others (2002) describe a bluff about 30 feet high and 100 feet wide of highly silicified pyroxene diorite. The diorite is cut by several quartz veins 1 to 2 inches thick. Analyses of two samples of pyrite-bearing quartz and a sample of the mafic rock did not show any significant base or precious metals.
Geologic map unit (-149.406206087977, 67.1193813215111)
Mineral deposit model Insufficient information to assign.
Age of mineralization Insufficient information to assign.

Production and reserves

Workings or exploration Limited sampling by government agencies.
Indication of production None
Reserve estimates None.
Production notes None.

Additional comments

See also: West Fork occurrence (CH001).
MAS No. 0020310077

References

MRDS Number A012122

References

Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Chandalar and Wiseman quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-340, 205 p.
Cobb, E.H., and Cruz, E.L., 1983, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in the Chandalar quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-278, 91 p.
DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, 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, 2 vols.: Bureau of Land Management, Alaska Technical Report 50, 845 p.
Reporters J.M. Britton (Anchorage, Alaska); D.J. Grybeck (Contractor, U.S. Geological Survey)
Last report date 4/18/2010