Unnamed (along South Fork of the Fortymile River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; As; Bi
Ore minerals gold; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale EA
Quadrangle map, 1:63,360-scale A-2
Latitude 64.088
Longitude -141.7942
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the east shoreline of the South Fork of the Fortymile River, about 1.2 miles upstream from the mouth of Walker Fork. The occurrence is in section 25, T. 27 N., R. 18 E., of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence is in upper Paleozoic greenschist-facies metasedimentary and metavolcanic rocks (Werdon and others, 2001). Light-gray, sheared, siliceous muscovite-quartz phyllite is cut by a fault zone with pyrite-bearing quartz veins that contain 85 ppb gold, 4.2 ppm silver, 36 ppm arsenic, and 10 ppm bismuth (Szumigala and others, 2000).
Geologic map unit (-141.79648118669, 64.0876736181965)
Mineral deposit model Fault-hosted gold.
Age of mineralization Late Paleozoic or younger.
Alteration of deposit Muscovite-quartz phyllite is sheared and silicified.

Production and reserves

Indication of production None