Unnamed (3850 Nunatak west of Tarr Inlet)

The Unnamed (3850 Nunatak west of Tarr Inlet) 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 (3850 Nunatak west of Tarr Inlet)

Commodity

Primary: Copper
Secondary: Silver
Secondary: Zinc

Location

State: Alaska
District: Juneau

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: Porphyry Cu, skarn-related

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Skarn developed in calc-magnesian rocks. Skarn minerals include garnet and epidote.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chalcopyrite
Ore: Pyrite
Ore: Pyrrhotite
Gangue: Quartz

Comments

Comment (Exploration): Status = Inactive

Comment (Geology): Age = Tertiary.

Comment (Workings): Workings / Exploration = Surface occurrence only; samples of massive sulfide pods as much as 0.5 foot thick contained anomalous amounts of copper, zinc, and silver (Kimball and others, 1978, table C37, sample--location--number 27).

Comment (Deposit): Model Name = Skarn, massive sulfide -- similar to porphyry copper, skarn related (Cox and Singer, 1986; model 18a).

Comment (Deposit): Other Comments = Extensive ice cover which could conceal skarn- or porphyry copper-type deposits. The occurrence is in Glacier Bay National Park and Preserve.

Comment (Geology): Geologic Description = The occurrence area is extensively ice-mantled. Generally it is in an area where the country rocks are volcanic rocks of Permian age intruded by granitic rocks of Cretaceous age (Brew and others, 1978). At the occurrence, skarn-like pods of massive sulfide as much as 0.5 foot across occur in marble and volcanic rocks at a granitic contact. Silicate minerals in the skarn include actinolite, chlorite, diopside, epidote, and garnet. The sulfides are mainly pyrite and pyrrhotite, and minor chalcopyrite. Chip samples (Kimball and others, 1978, table C37, location 27) contained as much as 770 ppm copper, 190 ppm zinc, and 1.5 ppm silver.

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

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): 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.

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