Unnamed

Occurrence in Alaska, United States with commodity Molybdenum

Geologic information

Identification information

Deposit ID 10000247
MRDS ID A010286
Record type Site
Current site name Unnamed

Geographic coordinates

Geographic coordinates: -131.17179, 56.11976 (WGS84)
Relative position This unnamed occurrence is located at an elevation of about 3350 feet a few hundred feet upslope from a small (0.1 mile diameter) unnamed lake on a northwest-trending ridge drained by east-flowing tributaries to the lower Hulakon (Eulachon) River (Elliott and Koch, 1981, p. 8, loc. 11). The location is accurate to within about a quarter of a mile.
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Molybdenum Primary

Materials information

Materials Type of material
Molybdenite Ore
Diopside Gangue
Garnet Gangue
Quartz Gangue

Alteration

  • (Local) Formation of calc-silicate skarn in amphibolite country rock

Mineral occurrence model information

Model code 60
USGS model code 18c
Deposit model name Skarn Zn-Pb
Mark3 model number 22
Model code 62
USGS model code 18d
Deposit model name Skarn Fe

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Skarn (Tactite)

Nearby scientific data

(1) -131.17179, 56.11976

Comments on the geologic information

  • Geologic Description = The country rocks in the general area of this occurrence are Mesozoic or Paleozoic paragneiss and orthogneiss, and subordinate amphibolite and marble (Elliott and Koch, 1981; Koch, 1997). ? the mineral occurrence consists of small, irregular pods of garnet-diopside skarn containing 1% disseminated molybdenite (Elliott and Koch, 1981, loc. 11). The skarn, which is accompanied by calc-silicate rock, forms pods and discontinuous disrupted layers(?) in amphibolite. The molybdenite occurs as minute discrete flakes in the skarn, and in and near glassy quartz veinlets (Koch, 1997, p. 31). Pelitic paragneiss about 1.5 miles north of this occurrence contains disseminated minute flakes of molybdenite, and geochemically anomalous Ag and Sn (Koch, 1997, p. 31). Koch (1997, p. 30-32) also reports anomalous values of Ag, Au, Cu, Mo, Sn, and Zn in a few geochemical samples collected by the U. S. Geological Survey in the late 1970's near this occurrence.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Petersburg

Comments on the workings information

  • Workings / Exploration = Pelitic paragneiss about 1.5 miles north of this occurrence contains disseminated minute flakes of molybdenite, and geochemically anomalous Ag and Sn (Koch, 1997, p. 31). Koch (1997, p. 30-32) also reports anomalous values of Ag, Au, Cu, Mo, Sn, and Zn in a few geochemical samples collected in the area near this occurrence by the U.S.Geological Survey in the late 1970's.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A010286
USGS Alaska Resource Data File ARDF BC011

Bibliographic references

  • Deposit

    Elliott, R.L., and Koch, R.D., 1981, Mines, prospects, and selected metalliferous mineral occurrences in the Bradfield Canal quadrangle, Alaska: U.S. Geological Survey Open-File Report 81-728-B, 23 p., 1 sheet, scales 1:250,000 and 1:63,360.

  • Deposit

    Koch, R.D., 1996, Reconnaissance geologic map of the Bradfield Canal quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 81-728-A, 35 p., 1 sheet, scale 1:250,000.

  • Deposit

    Koch, R.D., 1997, Metalliferous mineral resource potential in the Bradfield Canal quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report 97-271, 57 p., 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Elliott and Koch, 1981

General comments

Subject category Comment text
Deposit Model Name = Skarn
Deposit Other Comments = This occurrence is in Misty Fiords National Monument

Reporter information

Type Date Name Affiliation Comment
Reporter 17-MAY-1998 H. C. Berg U.S. Geological Survey