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Powdermilk

Prospect in Alaska, United States with commodities Silver, Lead, Zinc, Barium-Barite, Cadmium
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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 10003092
MRDS ID A015622
Record type Site
Current site name Powdermilk

Geographic coordinates

Geographic coordinates: -160.79359, 67.45946 (WGS84)
Relative position The Powdermilk prospect is just southeast of the confluence of the two major headwater forks of a major, unnamed, southeast flowing tributary of the Omar River. Coordinates are for the approximate center of the occurrence. The prospect covers an area of 2 square kilometers. It is in sections 24, 25, T. 24 N., R. 10 W., of the Kateel River Meridian. Schmidt and Allegro (1988), location 157.

Site location context

Political divisions (FIPS codes)

Northwest Arctic(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Baird Mountains B-4(quadrangle 1:63,360 scale)

Baird Mountains S(quadrangle 1:100,000 scale)

Baird Mountains C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Kobuk River(hydrologic unit)

Kobuk-Selawik Rivers(hydrologic accounting unit)

Northwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Lead Primary
Zinc Critical Primary
Barium-Barite Critical Secondary
Cadmium Secondary

Materials information

Materials Type of material
Galena Ore
Pyrite Ore
Sphalerite Ore
Barite Gangue

Alteration

  • (Local) Surficial weathering consists of rare iron oxide staining and local clay alteration.

Mineral occurrence model information

Model code 224
USGS model code 32a
Deposit model name Mississippi Valley, S.E. Missouri Pb-Zn
Mark3 model number 42

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Dolomite

Nearby scientific data

(1) -160.79359, 67.45946
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Powdermilk deposit consists of disseminations and clots (under 2.5 centimeter diameter) of sphalerite, galena, and rare pyrite in Devonian light-gray dolostone (Schmidt and Allegro, 1988). The sphalerite is coarsely crystalline, locally zoned, and medium to dark brown and red. Barite forms veins in the dolostone. Soil samples from the western river bank exposure contain as much as 1600 ppm Pb, 420 ppm Zn and 7.2 ppm Ag. Rock samples from the more oxidized, eastern creek exposure contain as much as 280 ppm Pb, 230 ppm Zn and 21 ppm Ag. Rock samples contain as much as 20% sphalerite, 8% galena and 5% pyrite.? the host dolostone strikes NE and dips nearly vertically at the prospect. Synformal structure is suggested. Some gray limestone occurs east of the prospect. The Powdermilk deposit is similar to southeast Missouri Pb-Zn (Cox and Singer, 1986; model 32a) in host rock and mineralization. The sulfides are epigenetic with respect to the host dolostone. Mineralization may be structurally controlled by the synform (Schmidt and Folger, 1986).
  • Age = Devonian

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Kiana

Comments on the workings information

  • Workings / Exploration = The U.S. Geological Survey did reconnaissance mapping, took 39 soil samples along a sample line, and collected additional rock and pan concentrate samples from the area (Zayatz and others, 1988).

Reference information

Bibliographic references

  • Deposit

    Schmidt, J.M., and Folger, P.F., 1986, Lead-zinc-silver mineralization in Paleozoic dolostones, Powdermilk prospect, Baird Mountains B-4 quadrangle: in Bartsch-Winkler, S., and Reed, K.M., eds., Geologic studies in Alaska by the USGS during 1985: U.S. Geological Survey Circular 978, p. 19-21.

  • Deposit

    Schmidt, J.M., and Allegro, G.L., 1988, Map showing mineral occurrences and indicators in the Baird Mountains quadrangle, northwestern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1992, 1 sheet, scale 1:250,000.

  • Deposit

    Zayatz, M.R., Thompson, W.B., Bailey, E.A., Sutley, S.J., Folger, P.F., Karl, S.M., and Schmidt, J.M., 1988, Analytical results and sample locality maps of mineralized and unmineralized rock samples from the Baird Mountains quadrangle, Alaska: U.S. Geological Survey Open-File Report 88-256-A, 159 p., 2 plates, scale 1:250,000.

Comments on the references

  • Primary Reference = Schmidt and Folger, 1986

General comments

Subject category Comment text
Deposit Model Name = Southeast Missouri Pb-Zn (Cox and Singer, 1986; model 32a).

Reporter information

Type Date Name Affiliation Comment
Reporter 29-DEC-99 Williams, Anita U.S. Geological Survey

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.