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Unnamed (upper Wachusett Inlet)

Occurrence in Alaska, United States with commodities Copper, Molybdenum, Silver
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Geologic information

Identification information

Deposit ID 10002268
MRDS ID A013171
Record type Site
Current site name Unnamed (upper Wachusett Inlet)
Related records 10233947

Geographic coordinates

Geographic coordinates: -136.35489, 58.95473 (WGS84)
Relative position This occurrence is in upper Wachusett Inlet, about 3 miles below the head of the inlet. The occurrence is on the shore line on the east side of the inlet. The location is accurate within 0.1 mile.? Most of the slope above the deposit is covered by Plateau Glacier or its morainal deposits. The occurrence is about 2 miles south-southwest of the Bruce Hills copper-molybdenum deposit (MF037). The location of the prospect is shown on an inset to figure C64 (Kimball and others, 1978). It is incorrectly located by Cobb (1972) and by MacKevett and others (1971).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Molybdenum Primary
Silver Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Molybdenite Ore
Pyrite Ore
Quartz Gangue

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite

Nearby scientific data

(1) -136.35489, 58.95473
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Comments on the geologic information

  • Geologic Description = A copper-molybdenum-bearing vein cuts quartz diorite of Cretaceous age. The area is only recently free of glacial ice, and mapping is of reconnaissance type. Brew and others (1978, pl. 1A) show most of the area as granitic rock of Cretaceous age. The quartz diorite is cut by andesite and pegmatite dikes and by quartz veins.? At the prospect, which is at the shore line, a narrow quartz -sulfide vein can be traced for about 50 feet, and projected as a brecciated iron-stained vein for another 75 feet. The vein is up to 0.7 foot thick and contains about 25 percent chalcopyrite by volume. Molybdendite and pyrite are also present. Selected vein samples contain as much as 7.4 percent copper and 1500 ppm molybdenum. The vein strikes north-northeast, subparallel to the shore line, and dips steeply to the northwest.
  • Age = Cretaceous or younger.

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

Comments on the reserve resource information

  • Reserves = Based on the surface samples, and calculated over a 4-foot width, the occurrence is an 800-ton resource containing 0.44 percent copper, 0.05 percent molybdenum, and 0.034 ounce per ton silver (Kimball and others, 1978).

Comments on the workings information

  • Workings / Exploration = The area has been explored by surface pits and trenches cut for samples. As sampled by the Bureau of Mines (Kimball and others, 1978, p. C307-C310), a chalcopyrite rich vein 0.7 foot thick contained 7.4 percent copper and 0.02 percent molybdenum. Other select samples ranged from 0.2 to 4.7 percent copper and contained from 0.03 to 0.15 percent molybdenum. Silver ranged from 5 to 30 ppm.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A013171
USGS Alaska Resource Data File ARDF MF060

Bibliographic references

  • 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.

  • 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

    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.

  • 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.

Comments on the references

  • Primary Reference = Kimball and others, 1978

General comments

Subject category Comment text
Deposit Other Comments = Area has been very recently deglaciated by recession of Plateau Glacier. The area contains other copper-molybdenum deposits and occurrences and is favorable for prospecting. ? the site is within Glacier Bay National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 22-DEC-98 Hawley, C.C. Hawley Resource Group