Unnamed (south of West Fork Rainy Creek)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Cu; Ni
Ore minerals chalcopyrite; marcasite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-4
Latitude 63.3008
Longitude -146.001
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is at an elevation of about 4,800 feet, about 3.3 miles northeast of the mouth of Specimen Creek on Eureka Creek. It is about 0.3 mile north-northeast of the center of section 3, T. 19 S., R. 9 E.

Geologic setting

Geologic description

As described by Nokleberg and others (1992 [OF]; 1992 [MF]), the rocks in the area are Triassic gabbro to the south and Triassic greenstone to the north. Rose (1965) described the mineralization as a flat-lying lens about 3 feet thick and 10 feet long that consists of massive pyrrhotite, pyrite, and minor pyrite. The pyrrhotite is partly altered to marcasite. The lens is overlain by white, bleached marble with diopside and brown garnet; gabbro is beneath it (Bittenbender and others, 2007). A sample collected by Rose (1965) contained 0.37 percent copper, 0.5 percent nickel, 0.03 ounce of gold per ton, and 0.33 ounce of silver per ton. A sample collected by Nokleberg and others (1991) contained 0.43 percent copper and 12.5 parts per million silver. Bittenbender and others (2007) collected a sample across 2.5 feet of the lens of mineralization; it contained more than 15 percent iron, 659 ppm copper, 982 ppm nickel, 0.0003 ounce of gold per ton, and 0.009 ounce of silver per ton. As of 2007, the prospect was covered by a large block of claims held by Nevada Star Resource Corp. but there was no indication of any workings on it.
Geologic map unit (-146.003260637563, 63.3003807966639)
Mineral deposit model Copper-nickel skarn deposit?
Age of mineralization Possible Triassic or younger based on the age of some of the host rocks in the area but may be related to nearby Permian intrusive rocks.
Alteration of deposit Pyrrhotite oxidized to marcasite. Lens of mineralization associated with a diopside-garnet marble.

Production and reserves

Workings or exploration As of 2007, the prospect was on claims held by Nevada Star Resource Corp. but there was no indication of any substantial workings on it.
Indication of production None
Reserve estimates None.
Production notes None.


MRDS Number A011784


Reporters W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS); D.J. Grybeck (Contractor, USGS)
Last report date 5/13/2012