Unnamed (on upper Benson Creek)

The Unnamed (on upper Benson Creek) is a gold, silver, and copper 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: Unnamed (on upper Benson Creek)

Commodity

Primary: Gold
Primary: Silver
Primary: Copper

Location

State: Alaska
District: Kougarok

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

Not available

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Silicification (?) and oxidation; the development of silica-rich rocks at or near the the base of Paleozoic marble overlying characterizes this type of copper occurrence.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chalcopyrite
Ore: Malachite
Gangue: Quartz

Comments

Comment (Commodity): Gangue = Iron oxides

Comment (Geology): Age = Unknown; if stratigraphic controls are important then it is probably Paleozoic in age.

Comment (Exploration): Status = Probably inactive

Comment (Reference): Primary Reference = Cathcart, 1922

Comment (Workings): Workings / Exploration = A short adit was driven to explore this prospect before 1920.

Comment (Deposit): Model Name = Copper-bearing mineralization in silica-rich zones at or near base of marble.

Comment (Geology): Geologic Description = An adit at this location exposed two, 3- to 5-foot-wide, silica-rich zones in marble that contained chalcopyrite, malachite, and iron oxides (Cathcart, 1922). Mineralization was banded, discontinuous, and appeared to follow layering in the highly folded host rocks. Wimmler (1926, in Asher, 1969, DGGS R18) collected a sample of copper-rich material from what appears to be this locality that assayed 0.04 ounces gold per ton, 0.20 ounces silver per ton, and 1.75 % copper. In places, the contact of the mineralized rocks seems to extend into marble suggesting replacement. This deposit is one of many occurrences of copper mineralization in silica-rich rocks near the regional contact between marble in a lower Paleozoic metasedimentary assemblage and pelitic schist of possible Cambrian or Precambrian age (Till and others, 1986). This type of copper occurrence is present at several localities in the western Solomon quadrangle (Gamble, 1988) and has similarities to several in the Kougarok area of the northeastern Teller quadrangle. In the Teller quadrangle, the Ward mine (TE071) is an example of this type of copper mineral occurrence. The Ward mine has been described as a zone of silicification in marble above a thrust contact with underlying metapelitic schist (Sainsbury and others, 1969; Sainsbury, 1975, p. 90-94). The silica-rich rocks have been metamorphosed and commonly have a laminar fabric. Copper-bearing minerals, mostly malachite but also including azurite and in places chalcopyrite and possibly bornite, are disseminated in the silica-rich rocks. The minor sulfides tend to be along faint laminae and joints (Sainsbury and others, 1969, p. 22). Malachite and azurite also occur in small veins and veinlets in the silica-rich rocks. The summary characterization of this type of Seward Peninsula mineral deposit by Sainsbury (1975, p. 90-94) contains inconsistencies with some descriptions of these deposits. Their origin is uncertain and other possibilities should be considered. One possiblity is that the silica-rich rocks are quartzites and that there is a stratigraphic control to the Ward deposit and similar occurrences elsewhere on Seward Peininsula. Quarzite at the base of the regional carbonate assemblage is recognized elsewhere in the Kougarok Mountain area (Puchner, 1986, p. 1777).

References

Reference (Deposit): Gamble, B.M., 1988, Non-placer mineral occurrences in the Solomon, Bendeleben, and southern part of the Kotzebue quadrangles, western Alaska: U.S. Geological Survey Map MF-1838-B, 13 p., 1 sheet, scale 1:250,000.

Reference (Deposit): Wimmler, N.L., 1926, Lode deposits in Seward Peninsula: Alaska Territorial Department of Mines Miscellaneous Report 192-01, 10 p.

Reference (Deposit): Puchner, C.C., 1986, Geology, alteration, and mineralization of the Kougarok Sn deposit, Seward Peninsula, Alaska; Discussion reply: Economic Geology, v. 82, p. 2201-2204.

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): 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): Asher, R.R., 1969, Geology and geochemistry of part of the Iron Creek area, Solomon D-6 quadrangle, Seward Peninsula, Alaska: Alaska Division of Mines and Geology Geochemistry Report 18, 19 p.

Reference (Deposit): Sainsbury, C.L., 1975, Geology, ore deposits, and mineral potential of the Seward Peninsula, Alaska: U.S. Bureau of Mines Open-File Report 73-75, 108 p., 3 sheets, scale 1:250,000.

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.

Reference (Deposit): Cathcart, S.H., 1922, Metalliferous lodes in southern Seward Peninsula: U.S. Geological Survey Bulletin 722, p. 163-261.

Reference (Deposit): Sainsbury, C.L., Kachadoorian, Reuban, Hudson, Travis, Smith, T.E., Richards, T.R., and Todd, W.E., 1969, Reconnaissance geologic maps and sample data, Teller A-1, A-2, A-3, B-1, B-2, B-3, C-1, and Bendeleben A-6, B-6, C-6, D-5, and D-6 quadrangles. Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 377, 49 p., 12 sheets, scale 1:63,360.

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