Unnamed (near Desolation Glacier) (ARDF #MF015) Cu, Ni

Unnamed (near Desolation Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu; Ni
Other commodities	Au; Ti
Ore minerals	chalcopyrite; ilmenite; pentlandite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale	MF
Quadrangle map, 1:63,360-scale	D-5
Latitude	58.78
Longitude	-137.57
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	The occurrence is on the north side of Desolation Glacier about 1.5 miles above its foot and between 3000 and 4000 feet elevation. The location is accurate within about 0.25 mile; it is approximately the same as number 17 of Kimball and others (1978).

Geologic setting

Geologic description Disseminated pyrrhotite, pyrite, chalcopyrite occur in a 'gabbro diabase' dike with average width of 5-6 ft that is exposed for 200 feet . The rock also contains a reported 2-5 percent titanium and probably contains ilmenite. An average grade reported is 0.59 percent nickel, 0.62 percent copper, and 0.010 ounce per ton in gold (Mark-Anthony, 1977). Based on the content of nickel, pentlandite is probably present . The dike cuts the hornblende schist and gneiss unit of Brew and others (1978). Based on the mid-Tertiary age of the nickel-bearing layered mafic intrusions of the Fairweather Range (Goldfarb, 1997), the mafic dike probably is also Tertiary. Brew and others (1978) considered the pre-metamorphic age of the schist host rocks as possibly Precambrian; Berg and others (1972) interpreted it as Mesozoic.
Geologic map unit	(-137.5719093835, 58.7796383441682)
Mineral deposit model	Mineralized mafic dike probably affiliated with layered gabbro intrusions.
Age of mineralization	Tertiary.

Production and reserves

Workings or exploration	Average value from surface exposures was reported to be 0.59 percent nickel, 0.62 percent copper, and 0.01 ounce per ton gold; titanium ranged from 2-5 percent (Mark-Anthony, 1977, cited by Kimball and others, 1978, p. C124). The occurrence was found by private prospectors.
Indication of production	None
Additional comments Small deposit, but worthy of additional followup because of its grade. It was not found by the Bureau of Mines investigators in 1977 (Kimball and others, 1978, p. C124) during stormy weather. The occurrence is in Glacier Bay National Park and Preserve.

References

MRDS Number	A013140
References Berg, H.C., Jones, D.L., and Richter, D.H., 1972, Gravina-Nutzotin Belt--Tectonic significance of an upper Mesozoic sedimentary and volcanic sequence in southern and southeastern Alaska: U.S. Geological Survey Professional Paper 800-D, p. D1-D24. 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. Goldfarb, R J., 1997, Metallogenic evolution of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 4-34. 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. Mark-Anthony, Leo, 1977, Maps and notes on investigations in Glacier Bay, 1958-1960. (Unpublished material available at U.S. Bureau of Land Management library, Juneau, Alaska).
Reporters	C.C. Hawley (Hawley Resource Group)
Last report date	4/6/1999