Unnamed (near Mt. Barnard)

Occurrence in Alaska, United States with commodities Copper, Silver, Gold, Cobalt

Geologic information

Identification information

Deposit ID 10002215
MRDS ID A013116
Record type Site
Current site name Unnamed (near Mt. Barnard)
Related records 10185555

Geographic coordinates

Geographic coordinates: -136.90213, 59.08972 (WGS84)
Relative position This occurrence is at an elevation of 5,475 feet in Glacier Bay National Park and Preserve; it is at the top of a nunatak, 2.6 miles southeast of the summit of Mount Barnard. It is shown as location 38 on Plate III of Brew and others (1978) and location SE27 by Nokleberg and others (1987).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary
Cobalt Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Pyrrhotite Ore
Epidote Gangue

Alteration

  • (Local) Chloritization, epidotization, sericitization.

Mineral occurrence model information

Model code 72
USGS model code 19a
Deposit model name Polymetallic replacement
Mark3 model number 47

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
    Stratigraphic age (youngest) Late Cretaceous
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite

Nearby scientific data

(1) -136.90213, 59.08972

Comments on the geologic information

  • Geologic Description = The following description is summarized from Brew and others (1978).?Small pods up to 0.5 foot thick of pyrrhotite and pyrite with a trace of chalcopyrite are associated with andesite, greenstone, epidote, and thin bands of limestone or marble. Abundant chloritic and some sericitic alteration are in a contact metamorphic zone near a Cretaceous granitic intrusive. A grab sample of one pod contained 1,000 ppm copper, 0.1 ppm gold, 0.5 ppm silver, and 100 ppm cobalt. The mineralization is probably Cretaceous, based on the age of the granitic intrusive which is associated with it.
  • Age = Probably Cretaceous or younger based on its association with nearby granitic intrusive rocks (Brew and others, 1978).

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Juneau (Glacier Bay subdistrict)

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013116
USGS Alaska Resource Data File ARDF SK018

Bibliographic references

  • 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.

  • Deposit

    Cobb, E.H., 1981, Summaries of data and lists of references to metallic and selected nonmetallic mineral occurrences in the Skagway quadrangle, Alaska, Supplement to Open-File Report 78-316, Part A in Summaries of data to January 1, 1980: U.S. Geological Survey Open-File Report 81-82-A, 11 p.

  • Deposit

    Cobb, E.H., 1981, Summaries of data and lists of references to metallic and selected nonmetallic mineral occurrences in the Skagway quadrangle, Alaska, Supplement to Open-File Report 78-316, Part B in Lists of References to January 1, 1980: U.S. Geological Survey Open-File Report 81-82-B, 10 p.

  • Deposit

    Berg, H.C., 1984, Regional geologic summary, metallogenesis, and mineral resources of southeastern Alaska: U.S. Geological Survey Open-file Report 84-572, 298 p., 1 plate, scale approx. 1:600,000.

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

  • Deposit

    Cobb, E.H., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Skagway quadrangle, Alaska; Supplement to Open-File Report 78-316; Part B, Lists of references to January 1, 1980: U.S. Geological Survey Open-File Report 81-82-B, 10 p.

  • Deposit

    Cobb, E.H., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Skagway quadrangle, Alaska; Supplement to Open-File Report 78-316; Part A, Summaries of data to January 1, 1980: U.S. Geological Survey Open-File Report 81-82-A, 11 p.

Comments on the references

  • Primary Reference = Brew and others, 1978

General comments

Subject category Comment text
Deposit Model Name = Probable replacement deposit adjacent to intrusive (Cox and Singer, 1986; model 19a).
Deposit Other Comments = There are probably similar deposits in the vicinity, but the rugged terrain and glaciers hamper investigation (Brew and others, 1978). The deposit is within Glacier Bay National Park and Preserve where exploration and development is restricted.

Reporter information

Type Date Name Affiliation Comment
Reporter 04-FEB-2001 T.C. Crafford T. Crafford & Associates