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Unnamed (on upper Benson Creek)

Prospect in Alaska, United States with commodities Silver, Gold, Copper
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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. Host and associated rocks
  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 10001848
MRDS ID A012664
Record type Site
Current site name Unnamed (on upper Benson Creek)

Geographic coordinates

Geographic coordinates: -164.64441, 64.91237 (WGS84)
Relative position This lode prospect is in the headwaters of Benson Creek (SO123) at an elevation of about 1,000 feet. This is locality 6 of Cobb (1972, MF 445; 1978, OF 78-181).

Site location context

Political divisions (FIPS codes)

Nome(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Solomon D-6(quadrangle 1:63,360 scale)

Solomon NW(quadrangle 1:100,000 scale)

Solomon(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Nome(hydrologic unit)

Norton Sound(hydrologic accounting unit)

Northwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Primary

Comments on the commodity information

  • Gangue = Iron oxides

Materials information

Materials Type of material
Chalcopyrite Ore
Malachite Ore
Quartz Gangue

Alteration

  • (Local) Silicification (?) and oxidation; the development of silica-rich rocks at or near the the base of Paleozoic marble overlying characterizes this type of copper occurrence.

Host and associated rocks

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

Nearby scientific data

(1) -164.64441, 64.91237
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = An adit at this location exposed two, 3- to 5-foot-wide, silica-rich zones in marble that contained chalcopyrite, malachite, and iron oxides (Cathcart, 1922). Mineralization was banded, discontinuous, and appeared to follow layering in the highly folded host rocks. Wimmler (1926, in Asher, 1969, DGGS R18) collected a sample of copper-rich material from what appears to be this locality that assayed 0.04 ounces gold per ton, 0.20 ounces silver per ton, and 1.75 % copper. In places, the contact of the mineralized rocks seems to extend into marble suggesting replacement. This deposit is one of many occurrences of copper mineralization in silica-rich rocks near the regional contact between marble in a lower Paleozoic metasedimentary assemblage and pelitic schist of possible Cambrian or Precambrian age (Till and others, 1986). This type of copper occurrence is present at several localities in the western Solomon quadrangle (Gamble, 1988) and has similarities to several in the Kougarok area of the northeastern Teller quadrangle. In the Teller quadrangle, the Ward mine (TE071) is an example of this type of copper mineral occurrence. The Ward mine has been described as a zone of silicification in marble above a thrust contact with underlying metapelitic schist (Sainsbury and others, 1969; Sainsbury, 1975, p. 90-94). The silica-rich rocks have been metamorphosed and commonly have a laminar fabric. Copper-bearing minerals, mostly malachite but also including azurite and in places chalcopyrite and possibly bornite, are disseminated in the silica-rich rocks. The minor sulfides tend to be along faint laminae and joints (Sainsbury and others, 1969, p. 22). Malachite and azurite also occur in small veins and veinlets in the silica-rich rocks. The summary characterization of this type of Seward Peninsula mineral deposit by Sainsbury (1975, p. 90-94) contains inconsistencies with some descriptions of these deposits. Their origin is uncertain and other possibilities should be considered. One possiblity is that the silica-rich rocks are quartzites and that there is a stratigraphic control to the Ward deposit and similar occurrences elsewhere on Seward Peininsula. Quarzite at the base of the regional carbonate assemblage is recognized elsewhere in the Kougarok Mountain area (Puchner, 1986, p. 1777).
  • Age = Unknown; if stratigraphic controls are important then it is probably Paleozoic in age.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Probably inactive

Mining district

District name Kougarok

Comments on the workings information

  • Workings / Exploration = A short adit was driven to explore this prospect before 1920.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Cathcart, 1922

General comments

Subject category Comment text
Deposit Model Name = Copper-bearing mineralization in silica-rich zones at or near base of marble.

Reporter information

Type Date Name Affiliation Comment
Reporter 19-AUG-1999 Travis L. Hudson Applied Geology

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.