The Unnamed (near Purple Lake) is a molybdenum 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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Unnamed (near Purple Lake) MRDS details
Site Name
Primary: Unnamed (near Purple Lake)
Commodity
Primary: Molybdenum
Primary: Gold
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
Not available
Orebody
Not available
Structure
Not available
Alterations
Alteration Type: L
Alteration Text: Trondhjemite is sericitized and locally permeated with hydrothermal hematite.
Rocks
Not available
Analytical Data
Not available
Materials
Ore: Pyrite
Ore: Magnetite
Comments
Comment (Geology): Geologic Description = The country rock at this site is Silurian trondhjemite (Berg, 1972 [I 684]; Berg and others, 1988). The trondhjemite, which locally is sheared, sericitized, and permeated with hydrothermal hematite, was regionally metamorphosed to greenschist grade in Late Cretaceous time. The occurrences are in sheared, hydrothermally altered trondhjemite, and consist of disseminated pyrite, and of pyrite-magnetite veins associated with a 300-foot-wide shear zone. A sample of rusty, altered, granitic rock contained 0.14 ppm Au; a sample of a pyrite-magnetite vein contained 15 ppm Mo (Karl, 1992, loc. 43a, b).
Comment (Geology): Age = Probably Late Cretaceous or younger.
Comment (Reference): Primary Reference = Karl, 1992
Comment (Workings): Workings / Exploration = A sample of rusty, altered, granitic rock contained 0.14 ppm Au; and a sample of a pyrite-magnetite vein contained 15 ppm Mo (Karl, 1992, loc. 43a, b).
Comment (Deposit): Model Name = Disseminated sulfide and magnetite mineralization of undetermined origin.
References
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,
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.
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