Unnamed (near Jones River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Fe
Ore minerals chalcopyrite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MG
Quadrangle map, 1:63,360-scale B-1
Latitude 62.446
Longitude -153.241
Nearby scientific data Find additional scientific data near this location
Location and accuracy This unnamed occurrence is located on a northwest facing spur overlooking an unnamed tributary of Jones River; it is at an elevation of 4,900 feet (1,494 m) in the NW1/4 sec. 7, T. 27 N., R. 21 W., of the Seward Meridian. The reporter visited the site in 1984; at station no. 84BT113.

Geologic setting

Geologic description

This unnamed occurrence is a thick, sulfide-bearing, quartz-vein breccia hosted in the mid Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger subterrane (Bundtzen, Harris, and Gilbert, 1997).
The sulfide vein breccia zone averages about 45 meters wide, with individual veins and breccia zones subparallel to bedding in host sandstone and silty limestone. The zone strikes across a saddle in a northeasterly direction; it disappears into talus on both ends. Veins include an older anhedral variety of quartz that has been cut by younger euhedral quartz veins that introduced both chalcopyrite and pyrite. Breccia fragments of sedimentary country rock comprise about 15 percent of the vein material. Total sulfide content is estimated at about 1 percent of the total mineralized zone. No assay data is available. Metallic content is based on recognition of chalcopyrite and pyrite in the field.
Geologic map unit (-153.243231441911, 62.4454059741132)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c

Production and reserves

Workings or exploration The reporter investigated the site during geologic mapping for the Alaska Division of Geological and Geophysical Surveys in 1984. No assay data is available from the mineralized zone. Metallic content is based on recognition of chalcopyrite and pyrite in the field.
Indication of production None
Reserve estimates None.

References