Unnamed (east of Stony River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag
Ore minerals chalcopyrite; pyrite; pyrrhotite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale LH
Quadrangle map, 1:63,360-scale B-2
Latitude 61.2993
Longitude -153.6655
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 5,000 feet on the south flank of a ridge on the east side of Stony River valley. The map site is near the southeast corner of section 13, T 14 N, R 25 W, of the Seward Meridian. This is location 17 of MacKevett and Holloway (1977), location 6 of Resource Associates of Alaska (1976), and location 44 of Gamble and others (1989). It is included as an unnamed occurrence by Cobb and Reed (1981). It is approximately located, perhaps to within one-half mile.

Geologic setting

Geologic description

Cobb and Reed (1981) reported that chalcopyrite, pyrite, and pyrrhotite occur as blebs and disseminations in Cretaceous(?) metasedimentary rocks adjacent to a Tertiary granitic pluton. The mineralization is localized in metasiltstone and metaconglomerate adjacent to and in roof pendants of the quartz diorite to quartz monzonite pluton. The metasedimentary rocks contain blebs and vugs of epidote, quartz, and feldspar. The area is crosscut by a regional northwest-trending fault. A 1,500-foot-diameter gossan containing 20 percent pyrite lies to the north of the occurrence. Rock samples contain as much as 2,700 ppm copper and 7 ppm silver (Resource Associates of Alaska, 1976).
Geologic map unit (-153.667771921955, 61.2986397704817)
Mineral deposit model Disseminated sulfides in contact zone of granitic pluton
Age of mineralization Tertiary. Mineralization is in the altered zone around a Tertiary pluton.
Alteration of deposit Silicification and epidote replacement.

Production and reserves

Workings or exploration Reconnaissance sampling has been completed in this area.
Indication of production None

References