Unnamed (on tributary to Middle Fork of Kuskokwim River)

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

Geologic information

Identification information

Deposit ID 10307842
Record type Site
Current site name Unnamed (on tributary to Middle Fork of Kuskokwim River)

Geographic coordinates

Geographic coordinates: -154.45184, 62.20946 (WGS84)
Relative position This unnamed occurrence is located near the juncture of two second order tributaries to an unnamed stream draining into Middle Fork of Kuskokwim River. It is at an elevation of 2,700 feet (823 m) in the SW1/4 sec. 34, T. 25 N., R. 28 W., of the Seward Meridian. The reporter visited the site in 1998; at station no. 98BT441.

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-3(quadrangle 1:63,360 scale)

McGrath SE(quadrangle 1:100,000 scale)

McGrath C(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
Silver Primary
Copper Primary
Lead Primary
Iron Secondary
Molybdenum Secondary
Nickel Critical Secondary
Vanadium Critical Secondary
Zinc Critical Secondary

Materials information

Materials Type of material
Galena Ore
Marcasite Ore
Pyrite Ore
Sericite Gangue

Mineral occurrence model information

Model code 212
USGS model code 31b
Deposit model name Bedded barite

Nearby scientific data

(1) -154.45184, 62.20946

Economic information

Comments on the geologic information

  • Geologic Description = The unnamed occurrence consists of stratiform pyrite-marcasite-galena bands parallel to sedimentary bedding in black, carbonaceous shale of the Lower Ordovician to Lower Silurian, Post River Formation, a unit of the Dillinger subterrane (Gilbert and others, 1988; Bundtzen, Harris, and Gilbert, 1997). The mineralization occurs in several outcrops at creek level that can be traced for about 75 meters; the sulfide-bearing bands are about 3 meters thick. However, individual sulfide-bearing layers are rarely more than 5 centimeters thick, and are isoclinally deformed as are the sedimentary interlayers. Microprobe analysis showed galena grains impregnated in the pyrite-rich layers. . One grab sample of massive pyrite-marcasite-galena mineralization contained 2.4 grams/tonne silver, 135 ppm copper, 11.60 percent iron, 39 ppm molybdenum, 255 ppm nickel, 176 ppm lead, 168 ppm vanadium, and 208 ppm zinc.
  • Age = Lower Paleozoic if mineralization is syngenetic.

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 investigated the site in 1998 (T.K. Bundtzen and G.M. Laird, written communication, 1998). One grab sample of massive pyrite-marcasite-galena mineralization contained 2.4 grams/tonne silver, 135 ppm copper, 11.60 percent iron, 39 ppm molybdenum, 255 ppm nickel, 176 ppm lead, 168 ppm vanadium, and 208 ppm zinc.

Reference information

Comments on the references

  • Primary Reference = This description

General comments

Subject category Comment text
Deposit Model Name = Sedimentary exhalitive lead-zinc (?) (Cox and Singer, 1986; model 31b).
Deposit Other Comments = See other possible sedimentary exhalitive prospects in McGrath quadrangle (MG049, MG051, MG064, MG071, MG072, MG074).

Reporter information

Type Date Name Affiliation Comment
Reporter 22-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.

Authoritative Alaska resources

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