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Omar

Prospect in Alaska, United States with commodities Copper, 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. 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 10094088
MRDS ID A015621
Record type Site
Current site name Omar
Related records 10281700

Geographic coordinates

Geographic coordinates: -160.8836, 67.48946 (WGS84)
Relative position The main occurrences at the Omar prospect are centered approximately 0.5 mile northwest of Omar Mountain at an elevation of 1,500 to 2,000 feet. They are in sections 9 and 10, T. 24 N., R. 10 W., of the Kateel River Meridian. Grybeck (1977), location 8, and Schmidt and Allegro (1988), location 152.

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
Copper Primary
Cobalt Critical Secondary

Comments on the commodity information

  • Gangue = iron oxides

Materials information

Materials Type of material
Bornite Ore
Chalcopyrite Ore
Covellite Ore
Malachite Ore
Pyrite Ore
Tetrahedrite Ore
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Hydrothermal dolomitization.

Mineral occurrence model information

Model code 233
USGS model code 32c
Deposit model name Kipushi Cu-Pb-Zn (BC name is Carbonate-hosted Cu)
Mark3 model number none

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Dolomite
    Stratigraphic age (youngest) Late Devonian

Nearby scientific data

(1) -160.8836, 67.48946
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Omar deposit consists of copper and iron sulfides in discordant veinlets, blebs and stringers in Devonian carbonates. A 3-kilometer-long, complex fracture zone trends north northwest across the prospect and hosts the deposit. Highly leached gossans are in the southern and central areas of the prospect. Three samples of gossan contained 1,070 ppm copper, greater than 20,000 ppm copper, and 13,400 ppm copper. Mineralized zones containing chalcopyrite, bornite, covellite and malachite in breccias and fracture fillings range from 300 to 1,000 meters long and up to 30 meters wide. Bornite and chalcopyrite are the dominant copper sulfides. Typical samples of sulfide-bearing talus contain 9.6% Cu. A sample from the southwest slope of hill 2455 contained 15.39% copper; other samples collected along the 3-kilometer trend ranged from 0.1% Cu to 9.6% Cu (Degenhart and others, 1978). High values of cobalt accompany the copper sulfides, along with minor zinc and silver. The thickest intercepts from two drill cores 300 feet apart were 25 to 30 feet of 9% Cu. These holes intersected two parallel shear zones (C.G. Bigelow, personal communication, 1975). ? Microscopic examination shows that the chalcopyrite forms coherent exsolution lamellae and non-coherent blebs and dots within bornite or tetrahedrite. Solution of the host dolostone created open spaces which were filled by dolomite, sulfide and quartz. The mineralizing event occurred prior to metamorphism and deformation associated with the middle Jurassic to Cretaceous Brooks Range orogeny (Folger and Schmidt, 1986). The carbonate sequences at Omar have been folded into broad anticlines and synclines. Most rock units at Omar strike north-northeast to northwest. Dips vary from 6 degrees to vertical. The geologic setting and mineralization at Omar closely resemble those at Ruby Creek, 100 miles to the east in the Ambler quadrangle.
  • Age = Devonian.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Active?

Mining district

District name Kiana

Comments on the reserve resource information

  • Reserves = Based on results of two drill holes, Bear Creek Exploration calculated possible reserves of 200,000 tons of ore containing 9% copper.

Comments on the workings information

  • Workings / Exploration = The Omar deposit was discovered by Bear Creek Exploration in 1962 as a result of a regional geochemical reconnaissance program. Work done on the prospect includes geologic mapping, soil, silt and rock sampling, hand trenching, ATM and EM surveys and 19 core drill holes. The geophysical surveys produced indifferent results even though they were run in areas of known mineralization (C.G. Bigelow, personal communication, 1975).

Reference information

Bibliographic references

  • Deposit

    Degenhart, C.E., Griffis, R.J., McQuat, J.F., and Bigelow, C.G., 1978, Mineral studies of the western Brooks Range performed under contract to the U.S. Bureau of Mines, Contract #JO155089: U.S. Bureau of Mines Open-File Report 103-78, 529 p., 11 sheets.

  • Deposit

    WGM Inc., 1980, Non-fuel mineral resource study of Alaska: Anchorage, Alaska, WGM, Inc., unpublished report, 320 p. (Report held by NANA Regional Corporation, Anchorage, Alaska).

  • Deposit

    Jansons, Uldis, 1982, Cobalt content in samples from the Omar copper prospect, Baird Mountains, Alaska: U.S. Bureau of Mines Open-File Report MLA 109-82, 16 p.

  • Deposit

    Folger, P.F., and Schmidt, J.M., 1986, Geology of the carbonate-hosted Omar copper prospect, Baird Mountains, Alaska: Economic Geology, v. 81, p. 1690-1695.

  • 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

    U.S. Bureau of Land Management, 1989, Geology, Energy and Mineral Resources, Proposed Squirrel River Wild and Scenic River and adjacent area, Baird Mountains, northwest Alaska: U.S. Bureau of Land Management, Division of Mineral Resources, Kobuk District, 42 p.

  • Deposit

    Cobb, E.H., Mayfield, C.F., and Brosge, W.P., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in eleven quadrangles in northern Alaska (Arctic, Baird Mountains, Chandler Lake, DeLong Mountains, Demarcation Point, Howard Pass, Misheguk Mountain, Mount Michelson, Noatak, Point Lay, and Table Mountain); Supplement to Open-File Report 75-628; Part A, Summaries of data to January 1, 1981: U.S. Geological Survey Open-File Report 81-767-A, 25 p.

Comments on the references

  • Primary Reference = Degenhart and others, 1978; Folger and Schmidt, 1986

General comments

Subject category Comment text
Deposit Model Name = Kipushi Cu-Pb-Zn (Cox and Singer, 1986; model 32c).
Deposit Other Comments = Outcrops are rare at Omar and extensive frost-heaved rubble obscures most lithologic contacts.

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.