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  3. Mineral Resource Data System (MRDS)

Unnamed (on tributary of Cheeneetnuk River)

Occurrence in Alaska, United States with commodities Copper, Silver
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10307834
Record type Site
Current site name Unnamed (on tributary of Cheeneetnuk River)

Geographic coordinates

Geographic coordinates: -155.20984, 62.06444 (WGS84)
Relative position This unnamed occurrence is located on a north-south ridgeline overlooking an unnamed tributary of Cheeneetnuk River; it is at an elevation of 2,475 feet (754 m) in the SE1/4 sec. 19, T. 23 N., R. 32 W., of the Seward Meridian. The location corresponds to map number 138 in Gilbert (1981); his station no. 77WG203. The reporter visited the site in 1989.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

McGrath A-5(quadrangle 1:63,360 scale)

McGrath SW(quadrangle 1:100,000 scale)

McGrath(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Stony River(hydrologic unit)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary

Materials information

Materials Type of material
Pyrite Ore

Alteration

  • (Local) Axinite, secondary biotite.

Mineral occurrence model information

Model code 72
USGS model code 19a
Deposit model name Polymetallic replacement
Mark3 model number 47

Host and associated rocks

  • Host or associated Associated
    Rock type
    Stratigraphic age (youngest) Middle Eocene
    Chronological age 39.8

Nearby scientific data

(1) -155.20984, 62.06444
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = This unnamed occurrence is a sulfide gossan hosted in Upper Paleozoic argillite of the Mystic subterrane, adjacent to a Tertiary andesite dike (Gilbert, 1981; Wilson and others, 1998). The gossan trends northeast for 90 meters and may be related to the dike. Pyrite impregnates ferricrete gossan in one sample; otherwise sulfide minerals have been completely oxidized. The argillite is locally thermally upgraded to hornfels; axinite and secondary biotite are observed in talus and rubble crop. A mid-Tertiary (39.8 Ma) granite pluton (Solie and others, 1991) is exposed in low angle contact with the Upper Paleozoic argillite and probably underlies the ridge where the mineralization occurs. Surface dimensions of the gossan are not available. One grab sample of gossan contained 350 ppm copper and 0.3 grams/tonne silver (Gilbert, 1981).
  • Age = Unknown; possibly related to 39.8 Ma granite body nearby (Gilbert, 1981; Solie and others, 1991).
  • Age = Chronological age is for a granite body nearby.

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 = W.G. Gilbert found the occurrence during a geologic mapping program for the Alaska Division of Geological and Geophysical Surveys in 1977 (Gilbert, 1981). One grab sample of gossan contained 350 ppm copper and 0.3 grams/tonne silver (Gilbert, 1981).

Reference information

Comments on the references

  • Primary Reference = Gilbert, 1981

General comments

Subject category Comment text
Deposit Model Name = Polymetallic replacement (?) (Cox and Singer, 1986; model 19a).

Reporter information

Type Date Name Affiliation Comment
Reporter 10-DEC-98 T.K. Bundtzen Pacific Rim Geological Consulting

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.