Unnamed (south of Arrigetch Creek)

Occurrence in Alaska, United States with commodities Silver, Copper, Lead, Tin, Zinc, Arsenic, Bismuth, Fluorine-Fluorite, Tungsten

Geologic information

Identification information

Deposit ID 10001209
MRDS ID A011922
Record type Site
Current site name Unnamed (south of Arrigetch Creek)

Geographic coordinates

Geographic coordinates: -154.02344, 67.42961 (WGS84)
Relative position This site represents several occurrences that cover an area of 4 square miles south of Arrigetch Creek. The coordinates are for the approximate center of the area of occurrences, in sec. 5, T. 23 N., R. 22 E., of the Kateel River Meridian. The location is accurate to within one mile. The site corresponds to localities 33 through 35 of Grybeck and Nelson (1981).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Lead Primary
Tin Primary
Zinc Primary
Arsenic Secondary
Bismuth Secondary
Fluorine-Fluorite Secondary
Tungsten Secondary

Comments on the commodity information

  • Gangue = Calc-silicate minerals

Materials information

Materials Type of material
Chalcopyrite Ore
Sphalerite Ore
Magnetite Gangue

Alteration

  • (Local) Calc-silicate minerals.

Mineral occurrence model information

Model code 43
USGS model code 14b
Deposit model name Sn skarn

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Marble
    Rock unit name Skajit Limestone; Dominantly Marble, Some Interlayered Schist
    Rock description Skajit Limestone; Dominantly Marble, Some Interlayered Schist
    Stratigraphic age (youngest) Late Devonian

Nearby scientific data

(1) -154.02344, 67.42961

Comments on the geologic information

  • Geologic Description = This site consists of three contact-metamorphic (skarn) deposits adjacent to Devonian granite (Grybeck and Nelson, 1981). At one locality several tactite bodies up to 700 m long by 70 m thick at a granite-carbonate contact contain lenses and pods of magnetite, and minor disseminated chalcopyrite, sphalerite and unspecified tungsten minerals. At another locality, heterogeneous contact-metamorphic rocks include fluorite-magnetite rock, quartz-epidote skarn, epidote-garnet skarn and sphalerite-epidote skarn. Selected samples contain up to 150 ppm Ag, 1000 pm Bi, and more than 1 percent each of Sn, Pb, and Zn. A brief reconnaissance of a granite-phyllite contact revealed several tactite pods less than 5 m wide. The most prominent consists of magnetite with copper staining. Grab samples contain up to 1000 ppm each of As, Cu, Sn, and Zn. These occurrences probably are similar in origin to other Devonian contact-metamorphic deposits in nearby areas of the Brooks Range (Newberry and others, 1986).
  • Age = Devonian; related to the intrusion of Devonian pluton.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Koyukuk

Comments on the workings information

  • Workings / Exploration = Sites briefly visited during regional geologic mapping by the USGS in the late 1970s.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A011922
USGS Alaska Resource Data File ARDF SP016

Bibliographic references

  • Deposit

    Grybeck, D.J., and Nelson, S.W., 1981, Mineral deposit map of the Survey Pass quadrangle, Brooks Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1176-F, 1 sheet, scale 1:250,000.

  • Deposit

    Newberry, R.J., Dillon, J.T., and Adams, D.D., 1986, Regionally metamorphosed calc-silicate-hosted deposits of the Brooks Range, northern Alaska: Economic Geology, v. 81, p. 1728-1752

Comments on the references

  • Primary Reference = Grybeck and Nelson, 1981

General comments

Subject category Comment text
Deposit Model Name = Skarn (Cox and Singer, 1986; model 14b)
Deposit Other Comments = Located within Gates of the Arctic National Park.

Reporter information

Type Date Name Affiliation Comment
Reporter 20-SEP-1999 S.W. Nelson U.S. Geological Survey