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Sheep Mountain

Past Producer in Alaska, United States with commodities Clay, Copper, Gypsum-Anhydrite, Gold
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Host and associated rocks
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. Reporter information

Geologic information

Identification information

Deposit ID 10000977
MRDS ID A011649
Record type Site
Current site name Sheep Mountain
Related records 10282502

Geographic coordinates

Geographic coordinates: -147.47264, 61.83959 (WGS84)
Relative position Near upper reaches of Glacial Fan Creek, southern flank of Sheep Mountain, 3,300 ft south of VABM Gun. Accurate within 1.5 miles. Locality 48 of Cobb (1972) and locality 37 of MacKevett and Holloway (1977).

Site location context

Political divisions (FIPS codes)

Matanuska-Susitna(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Anchorage D-2(quadrangle 1:63,360 scale)

Anchorage NE(quadrangle 1:100,000 scale)

Anchorage(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Matanuska(hydrologic unit)

Knik Arm(hydrologic accounting unit)

South Central Alaska(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Clay Primary
Copper Primary
Gypsum-Anhydrite Primary
Gold Secondary

Materials information

Materials Type of material
Azurite Ore
Bornite Ore
Chalcocite Ore
Chalcopyrite Ore
Gypsum Ore
Kaolin Ore
Malachite Ore
Pyrite Ore
Calcite Gangue
Epidote Gangue
Quartz Gangue
Sericite Gangue
Serpentine Gangue

Alteration

  • (Local) Large area of south flank of Sheep Mountain is strained dark red from oxidation of pyrite in greenstone (Berg and Cobb, 1967). Oxidation of Cu minerals.

Host and associated rocks

  • Host or associated Host
    Rock type
    Stratigraphic age (youngest) Early Jurassic

Nearby scientific data

(1) Jtk
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Early Jurassic greenstone and minor interbedded sandstone and shale is intruded by numerous mafic dikes and at least one body of unmineralized Jurassic granite. Greenstone has been hydrothermally altered and contains at least 6 separate gypsiferous deposits in altered zones along joints and shear zones. Deposits composed of pods and stringers of gypsum, quartz, alunite, kaolin minerals, pyrite and serpentine minerals (Eckhart, 1953). The gypsum-bearing material averages 25 to 30 percent gypsum, with a maximum of 50 percent. ? In addition also reported from same general area are: (1) small irregular quartz-calcite-epidote veins in greenstone containing chalcopyrite, malachite, azurite and possibly bornite and chalcocite (Berg and Cobb, 1967); (2) disseminated chalcopyrite in greenstone over 5 ft thick zone subparallel to bedding (Martin and Mertie, 1914); (3) trace gold in samples of pyritic greenstone (Berg and Cobb, 1967); and (4) minor anomalous concentrations of copper and gold associated with some of the alteration zones and nearby veins (MacKevett and Holloway, 1977).
  • Age = Jurassic or younger; mineralization hosted by an Early Jurassic greenstone.
  • Age = Host rock is Early Jurassic.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Both

Comments on exploration

  • Status = Inactive

Mining district

District name Willow Creek

Comments on the production information

  • Production Notes = About 50 tons of gypsum had been mined (Eckhart, 1953). In addition, about 55 tons of clay was mined for the manufacture of fire brick and boiler lining.

Comments on the reserve resource information

  • Reserves = the six deposits indicated and inferred reserves contain about 659,000 short tons of gypsum material (Eckhart, 1953).

Comments on the workings information

  • Workings / Exploration = The gypsiferous material averages 25 to 30 percent gypsum, with a maximum of 50 percent. The six deposits indicated and inferred reserves contain about 659,000 short tons of gypsum material, of which about 50 tons of this material had been mined (Eckhart, 1953). In addition, about 55 tons of clay was mined for the manufacture of fire brick and boiler lining. Samples of pyritic greenstone assayed trace gold (Berg and Cobb, 1967), and nearby veins in alteration zones show concentrations of copper and gold (MacKevett and Holloway, 1977).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Eckhart, 1953

Reporter information

Type Date Name Affiliation Comment
Reporter 30-JUL-1998 D.P. Bickerstaff U.S. Geological Survey
Reporter 30-JUL-1998 S.W. Huss U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.