Unnamed (south of upper Gravel Creek)

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Mo
Ore minerals chalcopyrite; molybdenite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale A-1
Latitude 62.0786
Longitude -141.2527
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5 of Richter and others (1973), locality 50 of Richter and others (1975), and National Park Service locality WRST-88 (unpublished data).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 setting

Geologic description

Disseminated 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.

Production and reserves

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 comments

The prospect is in the Wrangell-St. Elias National Preserve.

References