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Unnamed (Knight Island, Snug Harbor)

Prospect, Inactive

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Commodities and mineralogy

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

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-2
Latitude 60.2643
Longitude -147.7186
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located near tidewater on the north side of Snug Harbor, 1.5 miles northwest of Discovery Point (see the 1:250,000 quadrangle for this feature). It is in the NE1/4 section 16, T. 2 N., R. 10 E., of the Seward Meridian. This is location 241 of Tysdal (1978 [MF-880-A]) and location S-38 of Jansons and others (1984). This location is accurate to 300 feet.

Geologic setting

Geologic description

The prospect consists of a shear zone in slate and graywacke of the Orca Group of early Tertiary age; the shear zone contains lenses of massive sulfide along with quartz veins (Nelson and others, 1985; Kurtak and Jeske, 1986). The shear zone is 3 to 5 feet wide; it trends N20E and dips steeply northwest. The surface exposure is strongly iron-stained. Sulfides consist of pyrrhotite, chalcopyrite, and sphalerite that are, along with quartz, in fractures and brecciated zones (Kurtak and Jeske, 1986). Workings on the prospect consist of a 70-foot-long adit that appears to parallel the trend of the mineralized zone for 55 feet, then crosscuts it. A single sample from the adit contained 110 ppm copper and 53 ppm zinc. An 8-foot chip sample collected from the iron-stained shear zone at the mouth of the adit contained 0.37 percent copper and 0.82 percent zinc (Kurtak and Jeske, 1986).
Geologic map unit (-147.720637765767, 60.2637261916545)
Mineral deposit model Besshi massive sulfide (Cox and Singer, 1986; model 24b)
Mineral deposit model number 24b
Age of mineralization Tertiary or younger; the occurrence is in rocks of the Orca Group of Tertiary age.
Alteration of deposit There is considerable limonite staining in the surface exposure of the shear zone.

Production and reserves

Workings or exploration Workings on the prospect consist of a 70-foot-long adit that appears to parallel the trend of the mineralized zone for 55 feet, then crosscuts it. A single sample from the adit contained 110 ppm copper and 53 ppm zinc. An 8-foot chip sample from the iron-stained shear zone at the mouth of the adit, contained 0.37 percent copper and 0.82 percent zinc (Kurtak and Jeske, 1986).
Indication of production None

References

MRDS Number A010535

References

Cobb, E.H., and Tysdal, R.G., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Blying Sound and Seward quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-621, 276 p.
Grant, U.S., and Higgins, D.F., Jr., 1909, Notes on geology and mineral prospects in the vicinity of Seward, Kenai Peninsula: U.S. Geological Survey Bulletin 379-C, p. 98-107.
Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, southcentral Alaska: U.S. Bureau of Mines Mineral Land Assessment 5-84, 218 p., 2 sheets, scale 1:250,000.
Johnson, B.L., 1918, Copper deposits of the Latouche and Knight Island districts, Prince William Sound: U.S. Geological Survey BuIletin 662-C, p. 193-220.
Kurtak, J.M., and Jeske, R.E., 1986, Mineral investigations in the Chugach National Forest, Alaska (Islands area): U.S. Bureau of Mines Open-File Report 54-86, 302 p., 1 sheet, scale 1:63,360.
Moffit, F.H., and Fellows, R.E., 1950, Coper deposits of the Prince William Sound district, Alaska: U.S. Geological Survey Bulletin 963-B, p. 47-80.
Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.
Tysdal, R.G., 1978, Mines, prospects, and occurrences map of the Seward and Blying Sound quadrangles, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-880-A, 2 sheets, scale 1:250,000.
Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 12/18/2001