|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||B-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Foley prospect includes several prospects centered at an elevation of about 4,300 feet about 2.1 miles north-northwest of the junction of the North and West Forks of Rainy Creek It is near the northeast corner of section 36, T. 18 S., R. 9 E.|
These prospect consist of: 1) several sulfide-bearing, garnet-pyroxene skarns in carbonate beds intruded by the Rainy ultramafic-mafic complex, and 2) sulfide-bearing basalt, diorite, gabbro, and serpentinite in the complex (Foley, 1992). The Rainy complex intrudes the Slana Spur Formation of Pennsylvanian and Permian age; the Formation includes some some carbonate layers. The Rainy complex is up to 5,000 feet thick, dips shallowly north, and can be traced for more than 15 miles; it is mainly serpentinized dunite with subordinate peridotite, pyroxenite, and gabbro (Nokleberg and others, 1992; Nokleberg and others, 1992; Bittenbender and others, 2007). The base of the complex is a layered gabbro as much as 1,500 feet thick.
The prospects were found by industry in the 1990s; examined and sampled by the Bureau Mines (Foley, 1992), the U.S. Geological Survey (Nokleberg and others, 1991), and the Bureau of Land Management (Bittenbender and others, 2007).The mineralization examined by Nokleberg and others (1991) consists of disseminated and nearly massive pods of pyrite, pyrrhotite, magnetite, and chalcopyrite with trace pentlandite, cobaltite, and safflorite, in chromite-bearing olivine cumulates. A sample contained more than 5,000 parts per million (ppm) chromium. A U.S. Bureau of Mines sample of gabbronorite rubble contained 0.9 percent nickel, 0.25 percent copper, 0.02 percent cobalt, 1,070 parts per billion (ppb) palladium, 725 ppb platinum, 300 ppb iridium, 70 ppb rhodium, and 60 ppb ruthenium. Massive sulfide float contains 0.41 percent copper, 0.09 percent cobalt, and 65 ppb palladium (Foley, 1992). Mineralized skarn samples taken near the contact of the Rainy complex contain as much as 6.2 ppm silver, 85 ppb gold, 0.05 percent cobalt, 2.0 percent copper, and 0.09 percent nickel. The area was examined by Bittenbender and others (2007) but they did not locate the prospects.
|Geologic map unit||(-145.926059122787, 63.3174829234633)|
|Mineral deposit model||Nickel-copper-PGE mineralization in a differentiated mafic-ultramafic complex; disseminated chromite in a layered mafic-ultramafic complex; Cu skarn (Cox and Singer, 1986; model 18b).|
|Mineral deposit model number||18b|
|Age of mineralization||Genetically related to the emplacement of a Late Triassic mafic-ultramafic complex.|
|Workings or exploration||Found by industry in the 1990s. Examined and sampled by the Bureau Mines (Foley, 1992), the U.S. Geological Survey (Nokleberg and others, 1991), and the Bureau of Land Management (Bittenbender and others, 2007).|
|Indication of production||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.
Foley, J.Y., 1992, Ophiolite and other ultramafic metallogenic provinces in Alaska (west of the 141th meridian): U.S. Geological Survey Open-File Report 92-20-B, 55 p.
Foley, J.Y., Burns, L.E., Schneider, C.L., and Forbes, R.B., 1989, Preliminary report of platinum group element occurrences in Alaska: Alaska Division of Geological and Geophysical Surveys Public Data File 89-20, 32 p., 1 map sheet, scale 1:2,500,000.
Nokleberg, W. J., Aleinikoff, J. N., Dutro, J. T., Lanphere, M. A., Silberling, N. J., Silva, S. R., Smith, T. E., and Turner, D. L., 1992, Map, tables, and summary of fossil and isotopic age data, Mount Hayes Quadrangle, eastern Alaska range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-D, 43 p., 1 sheet, scale 1:250,000.
Nokleberg, W.J., Aleinikoff, J. N., Lange, I. M.; Silva, S. R., Miyaoka, R. T., Schwab, C. E., Zehner, R. E., Bond, G. C., Richter, D. H., Smith, T. E., and Stout, J. H., 1992, Preliminary geologic map of the Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Open-File Report 92-594, 39 p. 1 sheet, scale 1:250,000.
Nokleberg, W.J., Lange, I.M., Roback, R.C., Yeend, Warren, and Silva, S.R., 1991, Map showing locations of metalliferous lode and placer mineral occurrences, mineral deposits, prospects, and mines, Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-C, 42 p., 1 sheet, scale 1:250,000.
|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|