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Rock

Prospect, Inactive

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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.

References

MRDS Number A010650

References

Berg, H.C., and Cobb, E.H., 1967, Metalliferous lode deposits of Alaska: U.S. Geological Survey Bulletin 1246, 254 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Seldovia quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-397, 1 sheet, scale 1:250,000.
Cobb, E.H., 1979, Summary of references to mineral occurrences (other than minerals fuels and construction materials) in the Seldovia quadrangle, Alaska: U.S. Geological Survey Open-file Report 80-87, 47 p
Grant, U.S., and Higgins, D.F., Jr., 1910, Preliminary report on the mineral resources of the southern part of Kenai Peninsula: U.S. Geological Survey Bulletin 442-D, p. 166-178.
MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.
Martin G.C., Johnson, B.L., and Grant, U.S., 1915, Geology and mineral resources of Kenai Peninsula, Alaska: U.S. Geological Survey Bulletin 587, 243 p.
Reporters Jeff A. Huber (Anchorage)
Last report date 2/25/1999