Unnamed (west mouth of Rendu Inlet) (ARDF #MF056) Cu

Unnamed (west mouth of Rendu Inlet)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu
Other commodities	Co; Ni
Ore minerals	chalcopyrite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale	MF
Quadrangle map, 1:63,360-scale	D-2
Latitude	58.913
Longitude	-136.628
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	The occurrence is near sea level at the west mouth of Rendu Inlet 0.45 miles northeast of VABM Rendu. It is about 1.5 miles north of the point between Rendu Inlet and Glacier Bay. The location is probably accurate within 0.1 mile. The location is number 38 of MacKevett and others (1971), number 33 0f Cobb (1972), and number 43 of Kimball and others (1978).

Geologic setting

Geologic description Iron-stained pyritic zones up to 20 feet long and 1 foot thick occur in bleached marble of the Paleozoic marble and hornfels unit of Brew and others (1978). The unit is probably correlative with post-Silurian pre-Triassic limestone of Seitz (1959). The bedded rocks are intruded by granitic rocks of Cretaceous age. A pyritic zone containing minor chalcopyrite and possibly pyrrhotite was sampled by MacKevett and others (1971, table 9). A selected sample from a thin pyrite-rich lens contained 1500 ppm copper, 700 ppm cobalt, and 1000 ppm nickel, suggesting the prescence of nickeliferous pyrrhotite as an additional phase.
Geologic map unit	(-136.629865501475, 58.9126076403615)
Age of mineralization	Cretaceous or younger.
Alteration of deposit	Bleaching of marble near sulfidized zones.

Production and reserves

Workings or exploration	Surface exposures only, 2 samples collected (MacKevett and others, 1971).
Indication of production	None
Additional comments Paleozoic marble invaded by granitic plutons of Cretaceous age. The area is in Glacier Bay National Park and Preserve.

References

MRDS Number	A013167
References 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., 7 sheets. 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. 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. 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. Seitz, J.F., 1959, Geology of Geikie Inlet area, Glacier Bay, Alaska: U.S. Geological Survey Bulletin 1058-C, p. 61-120.
Reporters	C.C. Hawley (Hawley Resource Group)
Last report date	4/9/1999