Unnamed (on Dubuque Mountain)

The Unnamed (on Dubuque Mountain) is a molybdenum and silver 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: Unnamed (on Dubuque Mountain)

Commodity

Primary: Molybdenum
Primary: Silver

Location

State: Alaska
District: Ketchikan

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: Low-sulfide Au-quartz vein

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Schistose trondhjemite is intensely sericitized. One iron-stained zone is associated with a dark-green intermediate dike about 10 feet thick.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrite
Ore: Magnetite
Ore: Hematite
Gangue: Quartz

Comments

Comment (Workings): Workings / Exploration = A sample of sulfide-bearing aplite contained 0.5 ppm Ag and 15 ppm Mo (Karl, 1992, loc. 41b).

Comment (Reference): Primary Reference = Karl, 1992

Comment (Geology): Age = the fissure veins probably are Late Cretaceous or younger. The mineralization associated with the dikes that cut the trondhjemite probably is Tertiary.

Comment (Geology): Geologic Description = The country rocks in the area of this site are undivided, metamorphosed Silurian and Ordovician volcanic, sedimentary, and intrusive rocks; and Silurian trondhjemite that intrudes the Silurian and Ordovician rocks (Berg, 1972, Berg and others, 1988). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. The occurrences consist of quartz fissure veins and iron-stained zones in foliated, sericitized trondhjemite, or associated with aplite and intermediate dikes that cut the trondhjemite (Berg, 1972, loc. 31; Karl, 1992, loc. 41a, b). One iron-stained zone is associated with a dark-green intermediate dike about 10 feet thick. The quartz veins contain pyrite and hematite, and the trondhjemite contains inch-long pods of magnetite and hematite. A sample of sulfide-bearing aplite contained 0.5 ppm Ag and 15 ppm Mo (Karl, 1992, loc. 41b).

Comment (Deposit): Model Name = Possibly low-sulfide Au-quartz veins (Cox and singer, 1986; model 36a). Disseminated magnetite mineralization of undetermined origin.

References

Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Reference (Deposit): Karl, S.M., 1992, Map and table of mineral deposits on Annette Island, Alaska: U.S. Geological Survey Open-File Report 92-690, 57 p., 1 map, scale 1:63,360.

Reference (Deposit): Berg, H.C., 1972, Geologic map of Annette Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-684, 8 p., 1 sheet, scale 1:63,360,

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