Mini Y Landslide

Prospect, Active?

Commodities and mineralogy

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

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-5
Latitude 63.3221
Longitude -146.2872
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Mini Y Landslide prospect is at an elevation of about 5,100 feet, about 1.5 miles east of the toe of the Eureka Glacier and about 5.9 miles northwest of the junction of Eureka Creek and Broxton Gulch. The prospect is about 0.2 mile south of the center of section 30, T. 18 S., R. 8 E.

Geologic setting

Geologic description

The rocks in the vicinity of the Mini Y Landslide prospect consists of Upper Triassic serpentinized peridotite and mafic gabbro interlayered with quartz diorite (Rose, 1966 ). The serpentinized rocks, informally called the Eureka ultramafic complex, occupy strands of the Broxson Gulch thrust fault (Nokleberg and others, 1991).
The prospect was examined and sampled by several companies in the 1990s and the 2000s and at various times from the 1980s to the early 2000s by the Alaska Division and Mines and Minerals, the U.S. Geological Survey, and the U.S. Bureau of Land Management.
Disseminated sulfide minerals are present in several types of ultramafic rocks and in skarn of probable ultramafic parentage in upper Landslide Creek. Plagioclase peridotite with pyrite, pyrrhotite, pentlandite, and chalcopyrite assayed 0.15 percent copper, 0.35 percent nickel, 0.4 percent chromium, 300 parts per billion (ppb) palladium, and 380 ppb platinum. A sample of magnetite-chalcopyrite-epidote-diopside skarn assayed 0.5 percent copper and 130 ppb gold (Foley and others, 1989; Foley and Summer, 1990; Foley, 1992; W.T. Ellis, unpublished data, 1996).
Bittenbender and others (2007) did not find any outcrop at this site; rather they found rubble that may be piled up by recent glaciation. They collected four samples of ultramafic and mafic rocks from the rubble; the best contained 13 ppb gold, 118 parts per million (ppm) cobalt, 806 ppm copper, 2,420 ppm nickel, 45 ppb platinum, and 41 ppb palladium.
Geologic map unit (-146.289465799943, 63.3216766644)
Mineral deposit model Nickel-copper-PGE mineralization in a differentiated mafic-ultramafic complex.
Age of mineralization Genetically related to the emplacement of a Late Triassic mafic-ultramafic complex.
Alteration of deposit All of the ultramafic rock units are moderately to strongly serpentinized; diopside-epidote skarn is locally developed.

Production and reserves

Workings or exploration The prospect was examined and sampled by several companies in the 1990s and the 2000s and at various times from the 1980s to the early 2000s by the Alaska Division and Mines and Minerals, the U.S. Geological Survey, and the U.S. Bureau of Land Management.
Indication of production None
Reserve estimates None.
Production notes None.

References

References

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