Unnamed (overlooking Middle Fork of Kuskokwim River)

Occurrence in Alaska, United States with commodities Silver, Iron, Molybdenum

Geologic information

Identification information

Deposit ID 10307841
Record type Site
Current site name Unnamed (overlooking Middle Fork of Kuskokwim River)

Geographic coordinates

Geographic coordinates: -154.45284, 62.22746 (WGS84)
Relative position The unnamed occurrence is located in a low saddle overlooking the Middle Fork of the Kuskokwim River at an elevation of 3,000 feet (915 m) in the SW1/4 sec. 27, T. 25 N., R. 28 W., of the Seward Meridian. The reporter visited the site in 1998 at station no. 98BT440.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Iron Secondary
Molybdenum Secondary

Materials information

Materials Type of material
Molybdenite Ore
Pyrite Ore
Epidote Gangue
Quartz Gangue

Mineral occurrence model information

Model code 58
USGS model code 18a
Deposit model name Porphyry Cu, skarn-related
Mark3 model number 9

Nearby scientific data

(1) -154.45284, 62.22746

Comments on the geologic information

  • Geologic Description = This unnamed occurrence is a skarn zone developed in a highly sheared limestone of Late Triassic age, a part of the Mystic subterrane (Gilbert and others, 1988; Bundtzen, Harris, and Gilbert, 1997). Massive pyrite bands averaging 8 centimeters in thickness occur in association with epidote-quartz gangue within a 10 meter wide skarn zone near a gabbro-diorite sill. One grab sample contained 10.75 percent iron, 100 ppm molybdenum, and 1.25 grams/tonne silver (T.K. Bundtzen and G.M. Laird, written communication, 1998).

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = This unnamed occurrence was investigated in 1998. One grab sample contained 10.75 percent iron, 100 ppm molybdenum, and 1.25 grams/tonne silver (T.K. Bundtzen and G.M. Laird, written communication, 1998).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF MG028

Bibliographic references

  • Deposit

    Gilbert, W.G., Solie, D.N., and Kline, J.T., 1988, Geologic map of the McGrath A-3 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 92, 2 sheets, 1:63,360 scale.

  • Deposit

    Bundtzen, T.K., Harris, E.E., and Gilbert, W.G., 1997, Geologic Map of the eastern McGrath quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 97-14, 34 pages, one sheet, scale 1:125,000.

Comments on the references

  • Primary Reference = This description

General comments

Subject category Comment text
Deposit Model Name = Iron-rich skarn (Cox and Singer, 1986; model 18a).

Reporter information

Type Date Name Affiliation Comment
Reporter 22-DEC-98 T.K. Bundtzen Pacific Rim Geological Consulting