Star Group

Site Name

Primary: Star Group
Secondary: Tonopah
Secondary: Rex

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Commodity

Primary: Gold
Primary: Silver

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Location

State: Alaska
District: Chandalar

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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: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:

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Physiography

Not available

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Mineral Deposit Model

Model Name: Low-sulfide Au-quartz vein

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Type: L
Alteration Text: Oxidation of sulfides in the quartz veins.

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Rocks

Role: Host
Age Type: Host Rock
Age Young: Devonian

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Analytical Data

Not available

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Materials

Ore: Arsenopyrite
Ore: Gold
Ore: Scorodite
Gangue: Quartz

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Comments

Comment (Geology): Age = Host rock is Devonian.

Comment (Exploration): Status = Inactive

Comment (Reference): Primary Reference = Chipp, 1970

Comment (Workings): Workings / Exploration = The Star prospect has been prospected by a 10-foot shaft on the Star No. 2 claim and by several pits and trenches on the Star No. 1 and 3 claims.

Comment (Deposit): Other Comments = See also: Summit prospect (CH041), Mikado mine(CH045), Little Squaw mine (CH040).

Comment (Deposit): Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Comment (Geology): Age = Middle Cretaceous based on arguments by Dillon (1982) that the age of emplacement of the gold-bearing quartz veins of the Koyukuk and Chandalar districts was between the Neocomian metamorphism of the Devonian host rocks and their erosional unroofing and cooling in Albian time.

Comment (Geology): Geologic Description = The Star claim group (including the Tonopah claim) covers one of the four principal auriferous quartz vein systems in the Chandalar area. The vein system of the Star group, like the other vein systems in the area, is localized along steeply-dipping, northwest-trending normal faults in Devonian quartz-muscovite schist, phyllite, and quartzite, intruded by Devonian mafic sills and dikes (Chipp, 1970). In general, the veins in this area are less than 10 feet thick and are discontinuous, pinching out within a few hundred feet or less. The veins are composed principally of white crystalline to microcrystalline quartz, and their sulfide content is generally less than 5 percent. The principal sulfides in relative order of abundance are arsenopyrite, galena, sphalerite, and pyrite. Scorodite and limonite commonly are oxidation products. The quartz veins exhibit evidence of shearing, indicating that they were emplaced before or during fault movement. Major structural features in the area include large-scale northeast-trending anticlines and synclines, northeast-trending thrusts, and the northwest-trending, high-angle cross faults.? the fault zone on which the Star group is located lies between the Mikado and Summit faults (Chipp, 1970). A prospect pit on the property exposed a 6-foot-wide, partly vuggy quartz vein containing visible arsenopyrite and scorodite. The vein trends approximately N70W and dips 70 to 90 degrees northeast. A grab sample assayed 11 ppm Au. Another pit exposed vuggy, brown-stained quartz containing phyllite inclusions and minor arsenopyrite. On the Tonopah claim (west of the airstrip on upper Big Creek) trenching has exposed a 50-foot-wide fracture zone containing numerous east-west-trending, vuggy, iron-stained quartz-filled fractures 2 inches or less in width. Chipp (1970) suggests that this zone is probably the continuation of the Star vein system.? the genesis of the gold deposits in the Chandalar district is still in question. Various authors have hypothesized genetic links to a variety of felsic and mafic igneous rocks from which the gold was remobilized during metamorphism (Mertie, 1925; Boadway, 1933; Chipp, 1970; Dillon, 1982).

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References

Reference (Deposit): Maas, K.M., 1987, Maps summarizing land availability for mineral exploration and development in northern Alaska, 1986: U.S. Bureau of Mines Open-File Report 10-87, 33 quadrangle overlays.

Reference (Deposit): Brosgi, W.P., and Reiser, H.N., 1972, Geochemical reconnaissance in the Wiseman and Chandalar districts and adjacent region, southern Brooks Range, Alaska: U.S. Geological Survey Professional Paper 709, 21 p.

Reference (Deposit): Heiner, L.E., and Wolff, E.N., eds., 1968, Mineral resources of northern Alaska, Final report, submitted to the NORTH Commission: Mineral Industry Research Laboratory, University of Alaska, Report 16, 306 p.

Reference (Deposit): Chipp, E.R., 1970, Geology and geochemistry of the Chandalar area, Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys Geologic Report 42, 39 p., 1 sheet, scale 1:36,000.

Reference (Deposit): Dillon, J.T., 1982, Source of lode and placer gold deposits of the Chandalar and upper Koyukuk Districts: Alaska Division of Geological and Geophysical Surveys Open-File Report 158, 25 p., 1 sheet, scale 1:250,000.

Reference (Deposit): DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000.

Reference (Deposit): Mertie, J.B., Jr., 1925, Geology and gold placers of the Chandalar district, in Brooks, A.H., and others, Mineral resources of Alaska, report on progress of investigations in 1923: U.S. Geological Survey Bulletin 773, p. 215-263.

Reference (Deposit): Grybeck, D.J., 1977, Known mineral deposits of the Brooks Range, Alaska: US Geological Survey Open-File Report 77-166C, 41 p., 1 sheet, scale 1:1,000,000.

Reference (Deposit): Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Chandalar and Wiseman quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-340, 205 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-457, 1 sheet, scale 1:250,000.

Reference (Deposit): Anderson, Eskil, 1944, Petrographic descriptions of rocks collected during 1944 field investigation in north-west Alaska, and lists of ore and rock samples and placer concentrates collected in northwestern and interior Alaska during 1945 field season: Alaska Territorial Department of Mines Miscellaneous Report 195-28, 76 p.

Reference (Deposit): Boadway, E.A., 1933, Report on Mikado and Little Squaw veins, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-7, 37 p.

Reference (Deposit): Boadway, E.A., 1932, Report on Sulzer properties, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-6, 23 p., 4 sheets.

Reference (Deposit): Cobb, E.H., and Cruz, E.L., 1983, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in the Chandalar quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-278, 91 p.

Reference (Deposit): Reed, I.M., 1930, Report on the Little Squaw area of the Chandalar mining district: Alaska Territorial Department of Mines Miscellaneous Report 31-4, 18 p.

Reference (Deposit): Maas, K.M., 1987, Maps summarizing land availability for mineral exploration and development in northern Alaska, 1986: U.S. Bureau of Mines Open-File Report 10-87, 33 sheets.

Reference (Deposit): Reed, I.M., 1927, Report on some of the quartz prospects of the Chandalar district: Alaska Territorial Department of Mines Miscellaneous Report 31-2, 4 p.

Reference (Deposit): Bundtzen, T.K., Eakins, G.R., and Conwell, C.N., 1982, Review of Alaska mineral resources 1981: Alaska Division of Geological and Geophysical Surveys Annual Report 1981, 48 p.

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