Unnamed (north of South Fork bridge)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
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 64.0779
Longitude -141.7719
Nearby scientific data Find additional scientific data near this location
Location and accuracy This unnamed occurrence is at the waterline on the west bank of the South Fork of the Fortymile River; it may be under water during times of high water. The occurrence is about 1.5 miles north of the South Fork bridge on the Taylor Highway, and about 1.5 miles south of the mouth of Walker Fork, on the western edge of section 31, T. 27 N., R. 19 E., of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

This prospect is in upper Paleozoic greenschist-facies metasedimentary and metavolcanic rocks (Werdon and others, 2001). Light-gray to black chert (silicified limestone?) is cut by white quartz stringers and discontinuous pyrite veins. Portions of the outcrop have a banded appearance, and other portions are distinctly brecciated with a light matrix and dark clasts. Some fractures are filled with an unidentified yellow-orange material. Overall, brecciation is minor, and it probably is associated with quartz veining. An assay of a representative sample of quartz-veined and pyrite-rich chert (silicified limestone?) breccia contains 65 ppm gold (Szumigala and others, 2000).
Geologic map unit (-141.774180225199, 64.0775741708851)
Age of mineralization The veins cut upper Paleozoic rocks.
Alteration of deposit Possible silicification of limestone?

Production and reserves

Indication of production None

References