Nunatak (south of Snowcap Mountain)

The Nunatak (south of Snowcap Mountain) is a silver, copper, and gold mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Nunatak (south of Snowcap Mountain)

Commodity

Primary: Silver
Primary: Copper
Primary: Gold
Secondary: Zinc
Secondary: Lead
Secondary: Nickel
Secondary: Cobalt

Location

State: Alaska
District: McGrath

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Polymetallic veins

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The sulfide-bearing veins may be variably altered and replaced mafic dikes.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Alloclasite
Ore: Arsenopyrite
Ore: Chalcopyrite
Ore: Erythrite
Ore: Galena
Ore: Glaucodot
Ore: Magnetite
Ore: Pyrite
Ore: Pyrrhotite
Ore: Sphalerite
Gangue: Amphibole
Gangue: Apatite
Gangue: Chlorite
Gangue: Epidote
Gangue: Plagioclase
Gangue: Quartz
Gangue: Clinopyroxene

Comments

Comment (Geology): Geologic Description = Barren quartz veins, quartz-amphibole veins, and sulfide-bearing veins occupy east-west trending, sub-vertical fractures in biotite-hornblende monzodiorite to quartz monzodiorite in this area (Gamble and others, 1989). Two sulfide-bearing veins at an elevation of 5,500 feet on the south end of a small nunatak are about 1 to 2 feet wide and contain 5 to 70 percent chalcopyrite, arsenopyrite, and magnetite, and lesser amounts of galena, sphalerite, pyrite, and pyrrhotite. Erythite (cobalt bloom) is locally present and gangue minerals in the sulfide-bearing veins include amphibole, apatite, clinopyroxene, chlorite, epidote, quartz, and plagioclase. Composite chip samples of these veins contain as much as 1.5 ppm gold, 150 ppm silver, and greater than 20,000 ppm copper, 2,000 ppm arsenic, and 2,000 ppm copper. Apatite is locally abundant in the veins, and some samples contain as much as 1 percent phosphorus. Other sulfide-rich samples from the area contain up to 12 ppm gold, 700 ppm silver, and 640 ppm bismuth, and greater than 20,000 ppm copper, 2,000 ppm arsenic, and 2,000 ppm cobalt. A sample that contains greater than 20,000 ppm arsenic, 5,000 ppm cobalt, and 10,000 ppm nickel and only 7 percent iron may be glaucodot- or alloclasite-bearing (Gamble and others, 1989). The gangue mineralogy of the sulfide-bearing veins may indicate that they are in part mineralized mafic dikes.

Comment (Exploration): Status = Inactive

Comment (Workings): Workings / Exploration = Reconnaissance sampling has been done in this area (Gamble and others, 1989).

Comment (Reference): Primary Reference = Gamble and others, 1989

Comment (Deposit): Model Name = Polymetallic veins? (Cox and Singer, 1986, model 22c)

Comment (Geology): Age = Cretaceous or Tertiary the veins crosscut granitic rocks that may be Late Cretaceous or Tertiary parts of the Alaska-Aleutian Range batholith.

References

Reference (Deposit): Gamble, B.M., Bailey, E. A., and Reed, B. L., 1989, Gold occurrences near Snowcap Mountain, Lime Hills B-2 quadrangle, Alaska: U.S. Geological Survey Open-File Report 89-0646, 8 p.

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