1. Mineral Resources
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  3. Mineral Resource Data System (MRDS)

Unnamed (in Terra Cotta Mountains)

Occurrence in Alaska, United States with commodities Arsenic, Gold, Antimony, Tungsten, Cobalt
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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. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10307879
Record type Site
Current site name Unnamed (in Terra Cotta Mountains)

Geographic coordinates

Geographic coordinates: -153.39681, 62.10148 (WGS84)
Relative position This unnamed occurrence is located in the Terra Cotta Mountains near the base of a northwesterly spur overlooking a north flowing, unnamed tributary of the South Fork of Kuskokwim River. It is at an elevation of 4,200 feet (1,280 m) in the NE1/4 sec. 12, T. 23 N., R. 23 W., of the Seward Meridian. The reporter visited the site in 1988; at station no. 88BT169.

Site location context

Political divisions (FIPS codes)

Bethel(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

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

McGrath SE(quadrangle 1:100,000 scale)

McGrath(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Arsenic Critical Primary
Gold Primary
Antimony Critical Primary
Tungsten Critical Primary
Cobalt Critical Secondary

Materials information

Materials Type of material
Arsenopyrite Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Extensive ferricrete gossan.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Nearby scientific data

(1) -153.39681, 62.10148
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = This unnamed occurrence is a quartz-sulfide vein swarm in altered dacitic tuffs of the Eocene, Terra Cotta Volcanic Field (Bundtzen, Harris, and Gilbert, 1997). Most of the material is in the form of talus and no exposures of the veins were observed. Some sulfide zones have been transformed into extensive gossan. The extent of the mineralized area was not measured. One sample contained 240 ppb gold, 2,200 ppm arsenic, 880 ppm tungsten, 110 ppm cobalt, and 200 ppm antimony (Bundtzen, Harris, and Gilbert, 1997).

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 = The reporter sampled the site in 1988 during geologic mapping for the Alaska Division of Geological and Geophysical Surveys (Bundtzen, Harris, and Gilbert, 1997). One sample contained 240 ppb gold, 2,200 ppm arsenic, 880 ppm tungsten, 110 ppm cobalt, and 200 ppm antimony.

Reference information

Comments on the references

  • Primary Reference = Bundtzen, Harris, and Gilbert, 1997

General comments

Subject category Comment text
Deposit Model Name = Polymetallic vein (Cox and Singer, 1986; model 22c).

Reporter information

Type Date Name Affiliation Comment
Reporter 09-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.