Unnamed (tributary to Clear Creek)

Site Name

Primary: Unnamed (tributary to Clear Creek)

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Commodity

Primary: Uranium
Primary: REE

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Location

State: Alaska
District: Koyuk

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Land Status

Not available

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

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

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Physiography

Not available

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Mineral Deposit Model

Not available

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Orebody

Not available

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Structure

Not available

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Alterations

Not available

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Rocks

Role: Associated
Age Type: Associated Rock
Age in Years: 92.800000+-2.600000
Dating Method: K-Ar
Age Young: Holocene

Role: Associated
Age Type: Associated Rock
Age in Years: 88.300000+-1.500000
Dating Method: K-Ar
Age Young: Holocene

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Analytical Data

Not available

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Materials

Ore: Allanite
Gangue: Topaz
Gangue: Sphene
Gangue: Magnetite
Gangue: Ilmenite
Gangue: Hornblende
Gangue: Hematite
Gangue: Anatase

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Comments

Comment (Geology): Age = the heavy mineral concentrates are from Holocene surficial materials but some of these have been derived from the Darby pluton. The Darby pluton is mid-Cretaceous; K/Ar ages for the Darby pluton are 88.3 +/- 1.5 and 92.8 +/- 2.6 Ma (Berry and others, 1976).

Comment (Exploration): Status = Inactive

Comment (Geology): Geologic Description = A heavy-mineral concentrate (concentration ratio of 600:1) from stream gravels at this locality contained 0.023% equivalent uranium (West, 1953). Minerals identified in this concentrate include pyrite, ilmenite, magnetite, anatase, hornblende, topaz, allanite, biotie, and sphene. This drainage crosses the eastern contact of the Darby pluton with metasedimentary rocks (Till and others, 1986). Many of the heavy minerals in the concentrates from stream sediments in the area are known accessory minerals in the Darby pluton. The widespread, elevated Nb values in stream sediments (Miller and Grybeck, 1973) and in heavy -mineral concentrates (West, 1953) of the Clear Creek-Vulcan Creek area to the north, may indicate specific mineralized zones or disseminations in late, felsic phases of the Darby pluton (Miller and Grybeck, 1973). The Darby pluton is a mid-Cretaceous granodiorite and granite that has elevated background levels of uranium and thorium (Miller and others, 1972; Miller and Bunker, 1976; Johnson and others, 1979). This pluton is considered the bedrock source of uranium that was mobilized and deposited in the Death Valley sandstone uranium deposit during the Eocene (Dickinson and others, 1987). K/Ar ages for the Darby pluton are 88.3 +/- 1.5 and 92.8 +/- 2.6 Ma (Berry and others, 1976).

Comment (Reference): Primary Reference = West, 1953

Comment (Deposit): Model Name = Disseminated uranium- and rare-earth-bearing minerals are probably accessory phases in the Darby pluton. Other types of deposits could be present in metasedimentary rocks of this drainage.

Comment (Workings): Workings / Exploration = There are no known workings; exploration in the region may have included reconnaissance stream sediment sampling and radiometric surveys.

Comment (Geology): Age = Chronological age is for the Darby pluton.

Comment (Geology): Ore Material = uraniferous titanium niobate mineral

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References

Reference (Deposit): Berry, A.L., Dalrymple, G.B., Lamphere, M.A., and Von Essen, J.C., 1976, Summary of miscellaneous potassium-argon age determinations, U. S. Geological Survey, Menlo Park, California, for the years 1972-1974: U.S. Geological Survey Circular 727, 13 p.

Reference (Deposit): Miller, T.P., and Grybeck, D.J., 1973, Geochemical survey of the eastern Solomon and southeastern Bendeleben quadrangles, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 553, 115 p.

Reference (Deposit): Miller, T.P., Grybeck, D.J., Elliott, R.L., and Hudson, T.L., 1972, Preliminary geologic map of the eastern Solomon and southeastern Bendeleben quadrangles, eastern Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 72-256, 11 p.

Reference (Deposit): Till, A.B., Dumoulin, J.A., Gamble, B. ., Kaufman, D.S., and Carroll, P.I., 1986, Preliminary geologic map and fossil data, Soloman, Bendeleben, and southern Kotzebue quadrangles, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 86-276, 10 p., 3 plates, scale 1:250,000.

Reference (Deposit): Miller, T.P., and Bunker, C.M., 1976, A reconnaissance study of the uranium and thorium contents of plutonic rocks of the southeastern Seward Peninsula, Alaska: U.S. Geological Survey Journal of Research, v. 4, p. 367-377.

Reference (Deposit): Johnson, B.R., Miller, T.P., and Karl, S., 1979, Uranium-thorium investigations of the Darby pluton, Seward Peninsula, Alaska: U.S. Geological Survey Circular 804-B, p. 68-70.

Reference (Deposit): Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Solomon quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-181, 185 p.

Reference (Deposit): West, W.S., 1953, Reconnaissance for radioactive deposits in the Darby Mountains, Seward Peninsula, Alaska, 1948: U.S. Geological Survey Circular 300, 7 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic resources map of the Solomon quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-445, scale 1:250,000.

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