Unnamed (west mouth of Shag Cove)

The Unnamed (west mouth of Shag Cove) is a copper mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Unnamed (west mouth of Shag Cove)

Commodity

Primary: Copper
Secondary: Zinc
Secondary: Silver
Secondary: Cobalt

Location

State: Alaska
District: Juneau; Inlet

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Polymetallic veins

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Local oxidation of copper minerals.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Azurite
Ore: Bornite
Ore: Chalcopyrite
Ore: Cuprite
Ore: Malachite
Ore: Pyrite
Ore: Pyrrhotite
Gangue: Quartz

Comments

Comment (Deposit): Model Name = Polymetallic vein of probable igneous affiliation (Cox and Singer, 1986; model 22c).

Comment (Workings): Workings / Exploration = There are no workings. The occurrence on the mainland contains as much as 3000 ppm copper, 700 ppm zinc, 200 ppm cobalt, and 1 ppm silver. A selected sample of a sulfide pod which crops out on the island contained 1.5 ppm silver, 260 ppm copper and 100 ppm cobalt. Kimball and others (1978) reported occurences of sulfide-bearing quartz veins 1/2 mile from the mouth of the cove and of sulfide-rich pods and sulfide-bearing quartz veins about 1 1/2 miles from the mouth of the cove.

Comment (Deposit): Other Comments = the site is in Glacier Bay National Park and Preserve.

Comment (Commodity): Gangue = sheared wall rock minerals

Comment (Geology): Geologic Description = Schist, marble, and hornfels derived from sedimentary and volcanic rocks of Paleozoic age crop out west of Shag Cove. A major northwest-striking fault underlies the Cove and is one of the major faults of the Glacier Bay area. A splay off the master fault appears to separate the metamorphic terrane from granitic rocks of Cretaceous age about 0.3 mile southwest of the cove (Brew and others, 1978). ? the mineralized structure is a 65-foot-wide shear zone that strikes northeast and dips steeply northwest--apparently between the master and splay faults, both of which strike northwest.? the shear zone contains quartz veins and subparallel sulfide-rich pods. Pyrrhotite and pyrite are the most abundant sulfide minerals. Chalcopyrite and bornite, partly oxidized to azurite, malachite and cuprite (?), occur in lesser amounts. Sulfide-rich pods of pyrite, pyrrhotite and bornite also occur on the small island off the point at the north end of Shag Cove. A sample from a 3-foot-long sulfide pod in the shear zone contained 3000 ppm copper, 700 ppm zinc, 200 ppm cobalt, and 1 ppm silver (MacKevett and others, 1978, p. 51, table 9). A selected sample from a pod exposed on the island contained 1.5 ppm silver, 260 ppm copper, and 100 ppm cobalt (Kimball and others, 1978, p. C366-367).

Comment (Reference): Primary Reference = Kimball and others, 1978

Comment (Geology): Age = Cretaceous or younger.

Comment (Exploration): Status = Inactive

References

Reference (Deposit): Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.

Reference (Deposit): Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375.

Reference (Deposit): Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mt. Fairweather and Skagway quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-316, 123 p.

Reference (Deposit): MacKevett, E.M., Jr., Brew, D.A., Hawley, C.C., Huff, L.C., and Smith, J.G., 1971, Mineral resources of Glacier Bay National Monument, Alaska: U.S. Geological Survey Professional Paper 632, 90 p., 12 plates, scale 1:250,000.

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