Unnamed (on Cape Kumlik)

Occurrence in Alaska, United States with commodities Copper, Silver, Gold, Molybdenum

Geologic information

Identification information

Deposit ID 10001665
MRDS ID A012442
Record type Site
Current site name Unnamed (on Cape Kumlik)

Geographic coordinates

Geographic coordinates: -157.48246, 56.62931 (WGS84)
Relative position This occurrence is located on the east coast of the mainland between Kujulik and Aniakchak Bays. The map site is about 1 mile inland from the easternmost tip of Cape Kumlik (MacKevett and Holloway, 1977, localities 3 and 7; Cox and others, 1981, locality 1). The site location is accurate to within 1/2 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary
Molybdenum Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Molybdenite Ore
Pyrite Ore
Barite Gangue
Quartz Gangue

Alteration

  • (Local) The rocks exhibit a zoned alteration pattern, with a central potassic core grading outward to quartz-sericite and silicification, and to peripheral propylitization.

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Tonalite
    Stratigraphic age (youngest) Pliocene
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite
    Rock unit name Meshik Formation;Meshik Formation;Meshik Formation;Meshik Formation
    Rock description Meshik Formation;Meshik Formation;Meshik Formation;Meshik Formation

Nearby scientific data

(1) -157.48246, 56.62931

Comments on the geologic information

  • Geologic Description = At this site a quartz diorite stock has intruded volcanic rocks of the Oligocene and Eocene Meshik Formation (Detterman and others, 1981). The occurrence is marked by a large color anomaly covering about 1 section. Chalcopyrite and pyrite occur in quartz(?) veinlets and as disseminations in both the intrusive and in the surrounding volcanic rocks (Hedderly-Smith, 1977). Barite has been noted in many stream-sediment samples.? Numerous rock-chip samples collected by Bear Creek Mining Company returned copper values in the 400 ppm to 1000 ppm range and several contained 1000 ppm to 2000 ppm copper (Hedderly-Smith, 1977). The highest value was 5600 ppm copper from a sample of the mineralized intrusive. Molybdenum and silver were indicated as low-order anomalies. Gold was detected in the 0.07ppm 0.31 ppm range. The higher gold values generally coincided with the higher copper values. Of 7 rock samples collected here in 1978 by the U.S. Geological Survey, only 1 contained strongly anomalous values in copper (2200 ppm) (Yount and others, 1978). Cox and others (1981) estimate a small tonnage of low grade mineralization.? the rocks at the center of the mineralized area exhibit potassic alteration (Hedderly-Smith, 1977). Quartz-sericite alteration and silicification occur to the east, south, and west of the central area in both intrusive and volcanic rocks. An outer zone of propylitization is present.
  • Age = Tertiary.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Alaska Peninsula

Comments on the reserve resource information

  • Reserves = This occurrence is estimated to have a small tonnage of low grade (Cox and others, 1981).

Comments on the workings information

  • Workings / Exploration = Resource Associates of Alaska did a stream-sediment geochemical survey in 1975 (Hedderly-Smith, 1977). Bear Creek Mining Company geochemically sampled and mapped the occurrence in 1977 (Hedderly-Smith, 1977). Most samples returned copper values in the 400 to 1000 ppm range. One sample of mineralized intrusive contained 5600 ppm copper. Low order molybdenum and silver anomalies were also detected. The U.S. Geological Survey (Yount and others, 1978) took 7 samples in 1978. The highest copper value obtained was 2200 ppm.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012442
USGS Alaska Resource Data File ARDF SW001

Bibliographic references

  • Deposit

    Yount, M.E., Cooley, E.F., and O'Leary, R.M., 1978, Sample location map, analytical data, and statistical summary of analyses of rock samples, Chignik and Sutwik Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-557, l sheet, scale l:250,000.

  • Deposit

    Cox, D.P., Detra, D.E., and Detterman, R.L., 1981, Mineral resource maps of the Chignik and Sutwik Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF- 1053-K, 2 map sheets, scale 1:250,000.

  • Deposit

    Detterman, R.L., Miller, T.P., Yount, M.E., and Wilson, F.H.,1981, Geologic map the Chignik and Sutwik Island quadrangles Alaska: U.S. Geologic Survey Miscellaneous Investigations Series Map I- 1229, 1 map sheet, scale 1:250,000.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.

  • Deposit

    Hedderly-Smith, D.A., 1977 Annual report, Alaska search, Koniag Inc. region: Bear Creek Mining Company, Spokane Office, 23 p. (Report held by Kennecott Alaska, Anchorage).

Comments on the references

  • Primary Reference = Hedderly-Smith, 1977

General comments

Subject category Comment text
Deposit Model Name = Porphyry copper (Cox and Singer, 1986, model 17)
Deposit Other Comments = This site is located on land selected by the Koniag Native Corporation.

Reporter information

Type Date Name Affiliation Comment
Reporter 31-JAN-2000 S.H. Pilcher U.S. Geological Survey