The Unnamed (northeast side of Willoughby Island) is a copper 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 (northeast side of Willoughby Island) MRDS details
Site Name
Primary: Unnamed (northeast side of Willoughby Island)
Commodity
Primary: Copper
Secondary: Cobalt
Secondary: Arsenic
Location
State: Alaska
District: Juneau
Land Status
Not available
Holdings
Not available
Workings
Not available
Ownership
Not available
Production
Not available
Deposit
Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:
Physiography
Not available
Mineral Deposit Model
Not available
Orebody
Not available
Structure
Not available
Alterations
Not available
Rocks
Not available
Analytical Data
Not available
Materials
Ore: Chalcopyrite
Ore: Pyrite
Ore: Lollingite
Gangue: Calcite
Comments
Comment (Exploration): Status = Inactive
Comment (Geology): Age = Late Cretaceous or younger.
Comment (Deposit): Other Comments = the deposit is in marble of Devonian and Silurian age; mineralization followed emplacement of mafic dikes of probable Late Cretaceous or Tertiary age. ? the site is in Glacier Bay National Park and Preserve.
Comment (Reference): Primary Reference = Reed, 1938
Comment (Workings): Workings / Exploration = The deposit has not been found since Reed's visit in the 1930s (Reed, 1938). Workings are unknown, but there probably were shallow pits and trenches on the eight claims staked on the deposit before 1902.
Comment (Deposit): Model Name = Massive sulfide replacement in marble. Distal deposit related to subjacent intrusive; deposits formed after late emplacement of mafic dikes.
Comment (Geology): Geologic Description = The northeastern part of Willoughby Island is underlain by massive and bedded limestone of Devonian and Silurian age, part of a major reefoid mass (Brew and others, 1978). Locally the marble is cut by mafic dikes of Late Cretaceous or Tertiary age. At this prospect, pyrite, loellingite (?) and chalcopyrite form massive replacement layers or lenses in marble. One such massive sulfide deposit was described as 5-feet-thick and traceable on strike for 15 feet (Reed, 1938). At least three other similar occurrences were reported nearby by Reed.
References
Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.
Reference (Deposit): Reed, J.C., 1938, Some mineral deposits of Glacier Bay and vicinity, Alaska: Economic Geology, v. 33, p. 52-80.
Reference (Deposit): Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p.
Reference (Deposit): Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375.
Reference (Deposit): MacKevett, E.M., Jr., Brew, D.A., Hawley, C.C., Huff, L.C., and Smith, J.G., 1971, Mineral resources of Glacier Bay National Monument, Alaska: U.S. Geological Survey Professional Paper 632, 90 p., 12 plates, scale 1:250,000.
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