Baultoff Creek

Site Name

Primary: Baultoff Creek
Secondary: Baultoff

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Commodity

Primary: Copper
Tertiary: Molybdenum
Tertiary: Gold
Tertiary: Silver

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Location

State: Alaska
District: Chisana

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Land Status

Land ownership: Federal
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

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Holdings

Type: Located Claim

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Workings

Not available

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Ownership

Owner Name: Gerald Wood
Info Year: 1984

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Mining Method: Unknown
Years of Production:
Organization:
Significant: Y
Deposit Size: M

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Physiography

Not available

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Mineral Deposit Model

Model Name: Porphyry Cu
Model Name: Porphyry Cu-Mo

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Type: L
Alteration: Gypsiferous

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Rocks

Name: Diorite
Role: Host
Age Type: Host Rock Unit
Age in Years: 114.000000+-
Dating Method: K-Ar
Age Young: Cretaceous

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Analytical Data

Not available

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Materials

Ore: Chalcopyrite
Ore: Pyrite
Gangue: Albite
Gangue: Quartz
Gangue: Actinolite
Gangue: Sericite
Unknown: Magnetite
Unknown: Bornite

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Comments

Comment (Geology): Geologic Description = At the Baultoff prospect, disseminated pyrite and chalcopyrite occur in hornblende diorite and quartz porphyry of the mid-Cretaceous, Klein Creek pluton (Matson and Richter, 1971 [OFR 71-202]: Richter and others, 1975; Hollister and others, 1975). A 400- by 1,000-meter central altered zone is characterized by albite, chlorite, sericite and late anhydrite veins. It is within a 2,000- by 3,000-meter outer zone marked by abundant sericite and pyrite. Local actinolite veins and disseminations are present in the alteration zones. A post-mineralization fault bounds the alteration zone to the east. Surface samples contain less than 0.25 percent copper, and average 0.10 percent copper and less than 0.01 percent molybdenum (Richter and others, 1975). Low amounts of gold and silver are also present. The deposit is estimated to contain 160 million tons with an average grade of 0.20 percent copper and very low amounts of molybdenum (Richter and others, 1975). The diorite and porphyry that host the deposit are part of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).

Comment (Reserve-Resource): Reserves = The deposit is estimated to contain 160 million tons with an average grade of 0.20 percent copper and very low amounts of molybdenum (Richter and others, 1975).

Comment (Workings): Workings / Exploration = Surface exploration and some diamond drilling have been used to evaluated this deposit. Average grades from surface sampling: 0.10% Cu, with all samples below 0,25% Cu and less than 0.01% Mo, Au and Ag also present (Richter and others, 1975, USGS MF-655K, loc. 53).

Comment (Reference): Primary Reference = Richter, D.H., Singer, D.A., and Cox, D.P., 1975, Mineral resources map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-655-K, 1 sheet, scale 1:250,000.

Comment (Deposit): Other Comments = The prospect is in the Wrangell-St. Elias National Preserve. This is one of 8 known porphyry copper deposits which make up the principal mineral resource potential of Nabesna quadrangle. See also: Orange Hill, Bond Creek, Carl Creek, and Horsfeld.

Comment (Age): Mid-Cretaceous; the diorite and porphyry that host the deposit are part of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).

Comment (Geology): Original Alteration entry - Potassic, propylitic; extensive. Locally gypsiferous alteration composed of central altered zone 400 m by 1000 m with chlorite,sericite, and albite cut by late stage anhydrite veins. Outer altered zones characterized by intense sericitization and pyritization.

Comment (Geology): Most recent Alteration = A 400- by 1,000-meter central altered zone is characterized by albite, chlorite, sericite and late anhydrite veins. It is within a 2,000- by 3,000-meter outer zone marked by abundant sericite and pyrite. Local actinolite veins and disseminations are present in the alteration zones. A post-mineralization fault bounds the alteration zone to the east (Richter and others, 1973).

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References

Reference (Deposit): Richter, D.H., Singer, D.A., and Cox, D.P., 1975, Mineral resources map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-655-K, scale 1:250,000.

Reference (Deposit): Hollister, V.F., Anzalone, S.A., and Richter, D.H., 1975, Porphyry copper belts of southern Alaska and contiguous Yukon Territory: CIM (Canadian Mining and Metallurgical) Bulletin, v. 68, no. 756, p. 104-112.

Reference (Deposit): Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eeastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820.

Reference (Deposit): Cobb, E.H., and Richter, D.H., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Nabesna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-927, 117 p.

Reference (Deposit): Richter, D.H., Matson, N.A., Jr., and Smoll, H.R., 1973, Reconnaissance geologic map of the Nabesna A-1 quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map 1-807, scale 1:63,360.

Reference (Deposit): Matson, N.A., and Richter, D.H., 1971, Geochemical data from the Nabesna A-1 quadrangle, Alaska: U.S. Geological Survey Open-File Report 71-0202, 10 p.

Reference (Ownership): ALASKA KARDEX 078-085

Reference (Deposit): Matson, N.A., and Richter, D.H., 1971, Geochemical data from the Nabesna A-1 quadrangle, Alaska: U.S. Geological Survey Open-File Report 71-0202, 10 p., loc. 4, samples 138, 139

Reference (Reserve-Resource): Engineering & Mining Journal 7905, p. 83

Reference (Deposit): MTA 82 No. E-56

Reference (Deposit): MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected nonmetalliferous 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.

Reference (Deposit): Engineering & Mining Journal 7905, p. 83, No. 144

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