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Unnamed (at head of tributary to Post River)

Occurrence in Alaska, United States with commodities Arsenic, Lead, Zinc
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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 10307882
Record type Site
Current site name Unnamed (at head of tributary to Post River)

Geographic coordinates

Geographic coordinates: -153.4668, 62.01748 (WGS84)
Relative position This unnamed occurrence is located at the base of a steep north-facing cliff near the cirque headwall of an unnamed northwest flowing tributary of Post River. It is at an elevation of 4,500 feet (1,372 m) in the NE1/4 sec. 10, T. 22 N., R. 23 W., of the Seward Meridian. The occurrence corresponds to map number 34 in Bundtzen, Harris, and Gilbert (1997). The reporter sampled the site in 1988; at station no. 88BT163.

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
Lead Primary
Zinc Critical Secondary

Materials information

Materials Type of material
Galena Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Strong ferricrete alteration.

Mineral occurrence model information

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

Host and associated rocks

  • Host or associated Host
    Rock type
    Stratigraphic age (youngest) Early Eocene
    Chronological age 37.5

Nearby scientific data

(1) -153.4668, 62.01748
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = This unnamed occurrence consists of a series of N70W, steeply dipping joints and fractures filled with quartz, pyrite, and euhedral galena grains. Width and strike length of the mineralized area was not determined. Host rock is a medium-grained, phaneritic variant of the Hartman pluton (Bundtzen, Harris, and Gilbert, 1997), which has been dated by K-Ar methods as 37.9 Ma (Solie and others, 1991). A strong ferricrete gossan is associated with the sulfide-bearing stockwork veins. One chip sample of of mineralized stockwork veins contained 500 ppm arsenic, 20 ppb gold, and 340 ppm zinc (Bundtzen, Harris, and Gilbert, 1997). Lead was not analyzed.
  • Age = Mineralization undated; host pluton is 37.5 Ma (Solie and others, 1991).
  • Age = Chronological age is for Host Rock.

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 visited the site in 1988. One chip sample of mineralized stockwork veins contained 500 ppm arsenic, 20 ppb gold, and 340 ppm zinc. Lead was not analyzed (Bundtzen, Harris, and Gilbert, 1997).

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.