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  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 Cr; Cu; Ni
Other commodities Ni
Ore minerals azurite; copper sulfides; magnetite; malachite

Geographic location

Quadrangle map, 1:250,000-scale CH
Quadrangle map, 1:63,360-scale A-6
Latitude 67.1333
Longitude -149.6435
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 3,000 feet, about 2.4 mile west of the junction of Siwash Creek and Mosquito Fork. It is about 0.2 mile southeast of the center of section 25, T. 27 N., R. 10 W.

Geologic setting

Geologic description

This occurrence was originally described as copper sulfides and copper staining at the contact between Devonian(?) black phyllite and slate and Devonian(?) pyroxene diorite and andesite flows (Brosgé and Reiser, 1964). Kurtak and others (2002) indicated that the diorite and andesite flows may be part of a 1,000-foot-wide band of mafic-ultramafic rocks bounded on both sides by chlorite-quartz schist. The mafic-ultramafic rock contains magnetite, is serpentinized at the margins of the band, and may be dunite. Samples of the serpentinized rock averaged 977 parts per million (ppm) nickel and 1,078 ppm chromite.
Geologic map unit (-149.64621013752, 67.1328766098691)
Mineral deposit model Insufficient information to assign.
Age of mineralization Insufficient information to assign.

Production and reserves

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

Additional comments

MAS No. 0020310085

References

MRDS Number A012123

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