|Quadrangle map, 1:250,000-scale||NB|
|Quadrangle map, 1:63,360-scale||A-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is about 1,500 feet south of upper Gravel Creek and 2,000 feet north-northwest of peak 7510. The prospect is about 0.5 mile east-southeast of the center of section 31, T. 4 N., R. 23 E. of the Copper River Meridian. This is locality 5 of Richter and others (1973), locality 50 of Richter and others (1975), and National Park Service locality WRST-88 (unpublished data). It is located to within a few hundred feet.|
Geologic descriptionDisseminated pyrite and minor chalcopyrite occur in diorite near its contact with Jurassic or Cretaceous siliciclastic rocks (Richter and others, 1973). The deposit is marked by a hydrothermal alteration zone 300 by 1,000 feet in size. Surface samples average less than 0.10 percent copper and less than 0.01 percent molybdenum (Matson and Richter, 1971 [OFR 71-202]; Richter and others, 1975). The deposit is estimated to contain 12 million tons of material with an average grade of 0.20 percent copper and very low molybdenum (Richter and others, 1975). The diorite host rock is considered part of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and others, 1975).
|Geologic map unit||(-141.254834609744, 62.0782771826698)|
|Mineral deposit model||Porphyry Cu-Mo (Cox and Singer, 1986; model 21a)|
|Mineral deposit model number||21a|
|Age of mineralization||Mid-Cretaceous; the diorite host rock is part of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).|
|Alteration of deposit||A hydrothermal alteration zone is developed over an area of about 300 by 1,000 feet. Oxidation has resulted in iron-staining of this area.|
|Workings or exploration||There has been some surface exploration.|
|Indication of production||None|
|Reserve estimates||The deposit is estimated to contain 12 million tons of material with an average grade of 0.20 percent copper and very low amounts of molybdenum (Richter and others, 1975).|
Additional commentsThe prospect is in the Wrangell-St. Elias National Preserve.
Matson, N.A., Jr., and Richter, D.H., 1971, Geochemical data from the Nabesna A-1 quadrangle, Alaska: U.S. Geological Survey Open-File Report 71-0202, 10 p.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||11/24/2002|