|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Crash prospect is at an elevation of about 5,120 feet, about 4.1 miles northwest of the junction of Broxson Gulch and Eureka Creek. It is about 0.4 mile east of peak 5540 and about 0.5 mile north of the center of section 33, T. 18 S., R. 8 E. The location is accurate.|
The Crash 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 The prospect was found by industry in the 1990s (W.T. Ellis, unpublished data, 1996). At this prospect, the sill is about 100 feet thick; it dips north about 40 degrees; and consists of differentiated pyroxenite and gabbro. The footwall of the sill is siliceous volcanic rocks; the hanging wall is argillite, slate, and graywacke. A layer in the sill is altered with plagioclase going to saussurite and pyroxene going to actinolite; malachite and garnierite staining is prominent locally. The gabbro contains as much as 7 percent disseminated sulfides and magnetite. The sulfides are mainly pyrrhotite with small amounts of chalcopyrite and pentlandite. Samples assayed as much as 0.09 percent copper, 0.42 percent nickel, 630 parts per billion (ppb) palladium, and 475 ppb platinum (W.T. Ellis, unpublished data, 1996).Bittenbender and others (2007) examined and sampled the prospect. Their best sample was from iron-stained peridotite that contained 1,315 parts per million (ppm) copper, 2,180 ppm nickel, 322 ppb platinum, 414 ppb palladium, and 85 ppb gold.
|Geologic map unit||(-146.227264671067, 63.315577548307)|
|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||The ultramafic rocks units are moderately to strongly serpentinized.|
|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|
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.
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.
Rose, A.W., 1966, Geological and geochemical investigations in the Eureka Creek and Rainy Creek areas, Mt. Hayes quadrangle, Alaska: Alaska Division of Mines and Minerals Geologic Report 20, 41 p., 3 maps [figures], scale 1:40,000.
|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|