Pioneer Creek

The Pioneer Creek is a chromium 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: Pioneer Creek

Commodity

Primary: Chromium

Location

State: Alaska
District: Anchorage

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Alaskan Cr-Pt (PGE)
Model Name: Podiform chromite (minor)

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Slight serpentinization of olivine.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chromite

Comments

Comment (Reference): Primary Reference = Rose, 1966

Comment (Workings): Workings / Exploration = Trenched by the U.S. Bureau of Mines in 1942. Calculated grades based on weighted average analysis for the lower zone was 6.8 percent chromite and 6.9 percent chromite for the upper zone (Bjorklund and Wright, 1948). The best exposure assayed 7.5 percent chromite across a 13.5 ft zone (Rose, 1966).

Comment (Deposit): Model Name = Podiform chromite or Alaskan PGE (Cox and Singer, 1986; models 8a or 9)

Comment (Deposit): Other Comments = Bjorklund and Wright (1948) considered the deposit to be too small and too low grade to be mineable under conditions prevailing in 1940's.

Comment (Geology): Geologic Description = Jurassic dunite of the Eklutna Sequence containing two mineralized zones about 400 ft apart containing chromite in stringers, small pods, and disseminations. These are separated by olivine and minor clinopyroxene (Bjorklund and Wright, 1948). The lower zone strikes N 50 W, and dips 37 to 78 NE, and can be traced for 50 ft in outcrops and trenches. The upper zone strikes N 10 W, and dips 35 NE, can be traced for 30 ft in trenches, and has a maximum width of 30 ft. There is evidence in the upper zone that indicates some of the dunite may be slumped talus blocks rather than in place (Rose, 1966). ? Calculated grades based on weighted average analysis was 6.8 percent chromite for the lower zone and 6.9 percent chromite for the upper zone (Bjorklund and Wright, 1948). The best exposure assayed 7.5 percent chromite across a 13.5 ft zone (Rose, 1966).

Comment (Exploration): Status = Inactive

Comment (Geology): Age = Lower to Middle Jurassic

References

Reference (Deposit): Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials in the Anchorage quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-1095, 184 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Anchorage quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-409, 1 sheet, scale 1:250,000.

Reference (Deposit): Barnes, F.F., 1948, Preliminary report on the geology along the route of a proposed tunnel to develop hydroelectric power from Eklutna Lake, Alaska: U.S. Geological Survey Open-File Report 54, 9 p.

Reference (Deposit): Bjorklund, Stuart and Wright, W.S., 1948, Investigation of Knik Valley chromite deposits, Palmer, Alaska: U.S. Bureau of Mines Report of Investigation 4356, 5 p.

Reference (Deposit): Clark, S.H.B., and Bartsch, S.R., 1971, Reconnaissance geologic map and geochemical analyses of stream sediment and rock samples of the Anchorage B-6 quadrangle, Alaska: U.S. Geological Survey Open-File Report 475, 63 p., 2 sheets, scale 1:36,360.

Reference (Deposit): MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.

Reference (Deposit): Clark, S.H.B., 1972, Reconnaissance bedrock geologic map of the Chugach Mountains near Anchorage, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map 350, 1 sheet, scale 1:250,000.

Reference (Deposit): Rose, A.W., 1966, Geology and chromite-bearing ultramafic rocks near Eklutna, Anchorage quadrangle, Alaska: Alaska Division of Mines and Minerals Geologic Report 18, 25 p., 1 sheet, scale 1:42,000.

Reference (Deposit): Berg, H.C., and Cobb, E.H., 1967, Metalliferous Lode Deposits of Alaska. U.S. Geological Survey Bulletin 1246, 254 p.

Reference (Deposit): MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

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