Moonlight Divide

Prospect in Alaska, United States with commodity Copper

Geologic information

Identification information

Deposit ID 10308278
Record type Site
Current site name Moonlight Divide

Geographic coordinates

Geographic coordinates: -164.45129, 64.79431 (WGS84)
Relative position The Moonlight Divide prospect is located on the ridge crest betweeen the headwaters of Moonlight Creek (SO099) and Ridgeway Creek (SO092) at about 1,400 feet elevation. This is locality 14 of Cobb (1972, MF 445; 1978, OF 78-181). Gamble (1988) shows two occurrences of this name farther west and this as his new locality 125.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary

Materials information

Materials Type of material
Malachite Ore
Quartz Gangue

Alteration

  • (Local) Silicification? The development of silica-rich rocks at or near the the base of Paleozoic marble overlying metapelitic rocks characterizes this type of copper occurrence.

Nearby scientific data

(1) -164.45129, 64.79431

Comments on the geologic information

  • Geologic Description = This prospect 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 and has similarities to several in the Kougarok area of the northeastern Teller quadrangle. In theTeller 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). Gamble (1988) describes rocks near this prospect as an iron-stained quartzite (or silicified marble) within marble with 2 to 3 percent pyrite; a sample contained 400 ppm As.
  • Age = Unknown; if stratigraphic controls are important then it is probably Paleozoic in age.

Economic information

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name Council

Comments on the workings information

  • Workings / Exploration = Some shallow prospect pits were dug and claims were staked (Smith, 1908).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF SO100

Bibliographic references

  • Deposit

    Smith, P.S., 1908, Investigations of mineral deposits of Seward Peninsula: U.S. Geological Survey Bulletin 345, p. 206-250.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

Comments on the references

  • Primary Reference = Smith, 1908

General comments

Subject category Comment text
Deposit Model Name = Copper-bearing mineralization in silica-rich zones at base of marble overlying metapelitic schist.

Reporter information

Type Date Name Affiliation Comment
Reporter 19-AUG-99 Travis L. Hudson Applied Geology