Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Zn
Ore minerals arsenopyrite; chalcopyrite; pyrite; pyrrhotite; sphalerite
Gangue minerals clay; quartz

Geographic location

Quadrangle map, 1:250,000-scale SV
Quadrangle map, 1:63,360-scale A-5
Latitude 59.221
Longitude -151.646
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Rock prospect is located on the north flank of Rock Mountain at about 1,100 feet of elevation. This is Cobb's (1972, MF-397) location 2 and is accurate to a quarter of a mile. Cobb (1979, OFR 80-87) summarized the relevant references under the name Rock.

Geologic setting

Geologic description

The discovery outcrop of the prospect is located on the contact of a graywacke of the Cretaceous Valdez Group with a Tertiary granite dike (Cobb, 1979 OFR 80-87). At this locality, the vein is 22 to 28 inches in width and strikes N19W with a dip of 60N. About 150 feet higher and to the south, what appears to be the same vein is exposed in two trenches where it is 36 to 44 inches wide. The vein contains quartz, arsenopyrite, chalcopyrite, sphalerite, pyrite, and pyrrhotite, but no precious metals are reported (Martin and others, 1915).
Geologic map unit (-151.648108976339, 59.2203319930432)
Mineral deposit model Low-sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Tertiary; possibly related to Tertiary granite dike.
Alteration of deposit Clay selvage along the vein margins.

Production and reserves

Workings or exploration Minor surface trenches. No assay results are reported.
Indication of production None
Reserve estimates None.