Alaska
Prospect

Nunatak (Muir Inlet)

Alaska, United States
MolybdenumCopperGoldSilver
⌖ Show on mapUSGS source ↗
Commodities
PrimaryMolybdenum
SecondaryCopper, Gold, Silver
Commodity typeM
Deposit
Model80: Porphyry Mo, low-F
Materials
Ore mineralsBornite, Chalcopyrite, Chrysocolla, Enargite, Magnetite, Malachite, Molybdenite, Pyrite, Pyrrhotite, Tetrahedrite
GangueCalcite, Quartz
Geology
AlterationThe alteration consists of minor K-feldspar and pyrometasomatic conversion of calc-units to calc-hornfels and skarn. Actinolite is locally developed in the skarn and actinolitic skarns appear to be more favorable for ore The tactitic skarn consists mainly of orthoclase and clinozoisite, with lesser amounts of diopside, garnet, quartz, and plagioclase. Rocks adjacent to the quartz granodiorite porphyry are silicified. Phlogopite, montmorillonite, calcite, and feldspar occur in the altered zones flanking some veins (MacKevett and others, 1971, p. 75).
Economic & production
Development statusProspect
Identification
Deposit ID10308916
MRDS IDD000846
RegionNA
Data scoreB
Coordinates58.98973, -136.1051
References
Twenhofel, W.S., 1946, Molybdenite deposits of the Nunatak area, Muir Inlet, Glacier Bay, in Twenhofel, W. S., Robinson, G. D., and Gault, H. R., Molybdenite investigations in southeastern Alaska: U.S. Geological Survey Bulletin 947-B, p. 7-38.Sanford, R.S., Apell, G.A., and Rutledge, F.A., 1949, Investigations of Muir Inlet or Nunatak molybdenum deposit, Glacier Bay, southeastern Alaska: U.S. Bureau of Mines Report of Investigations 4421, 6 p.Rossman, Darwin, 1963, Geology of the eastern part of the Mount Fairweather quadrangle, Glacier Bay, Alaska: U.S. Geological Survey Bulletin 1121-K, p. K1-K57.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.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.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.Moerlein, G.A., 1968, Geology and drilling results, Nunatak molybdenum prospect, Walper property, southeastern Alaska: Unpublished report available at U.S. Bureau of Land Management Library at Juneau, Alaska.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.Reed, J.C., 1938, Some mineral deposits of Glacier Bay and vicinity, Alaska: Economic Geology, v. 33, p. 52-80.