Prospect, Active?

Commodities and mineralogy

Main commodities Cr; Cu; Ni; Pd; Pt
Other commodities Au
Ore minerals chalcopyrite; magnetite; pentlandite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-5
Latitude 63.3173
Longitude -146.2028
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Notar prospect is at an elevation of about 4,900 feet about 3.8 miles north-northwest of the junction of Broxson Gulch and Eureka Creek. It is near the northwest corner of section 34, T. 18 S., R. 8 E. The location is accurate.

Geologic setting

Geologic description

The Notar prospect is in an east-trending, northward-dipping sill of Late Triassic, ultramafic and mafic rocks that are part of the Eureka complex (Rose, 1966; Nokleberg and others, 1992 [MF]; Nokleberg and others, 1992 [Open-File]; Bittenbender and others, 2007). The rocks in the area are mainly variably serpentinized dunite with some peridotite and gabbro.
The prospect was found by industry in the 1990s (W.T. Ellis, unpublished data, 1996). The mineralization is in olivine melagabbro that contains as much as 7 percent disseminated sulfides, mainly pyrrhotite with small amounts of chalcopyrite and pentlandite, and magnetite. Samples contained up to 0.11 percent copper, 0.17 percent nickel, 42 parts per billion (ppb) palladium, and 40 ppb platinum.
The prospect was examined and sampled by Bittenbender and others (2007). They collected 5 samples that contained up to 17 ppb gold, 88 ppb platinum, 344 parts per million (ppm) copper, 822 ppm chromium, and 2,900 ppm nickel. A sample of peridotite they collected south of the prospect contained 49 ppb gold, 27 ppb platinum, 22 ppb palladium, 653 ppm copper, and 1,540 ppm nickel.
Geologic map unit (-146.205064552446, 63.3168779600421)
Mineral deposit model Nickel-copper-PGE mineralization in a differentiated mafic-ultramafic sill.
Age of mineralization Genetically related to the emplacement of a Late Triassic mafic-ultramafic complex.
Alteration of deposit Dunite is variably serpentinized.

Production and reserves

Workings or exploration Found and sampled by industry in the 1990s; examined and sampled by the Bureau of Land Management in the early 2000s.
Indication of production None
Reserve estimates None.
Production notes None.



Bittenbender, P.E., Bean, K.W., Kurtak, J.M., and Deininger, James Jr., 2007, Mineral assessment of the Delta River Mining District area, east-central, Alaska: U.S. Bureau of Land Management, Alaska Technical Report 57, 675 p.
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