Unnamed (west head of Hugh Miller Glacier) (ARDF #MF052) Cu

Unnamed (west head of Hugh Miller Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu
Other commodities	Ag; Au; Fe; Mn
Ore minerals	arsenopyrite; chalcopyrite; pyrite
Gangue minerals	epidote; garnet

Geographic location

Quadrangle map, 1:250,000-scale	MF
Quadrangle map, 1:63,360-scale	D-3
Latitude	58.785
Longitude	-136.765
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	The occurrence is on a ridge west of the head of Hugh Miller Glacier at an elevation of about 4100 feet. It is about 0.75 mile east of Reid Glacier at a point about 4 miles above the terminous of the glacier at Reid Inlet. The location is accurate within 0.1 mile. The site of the occurrence is location number 50 of Kimball and others (1978).

Geologic setting

Geologic description The occurrence is in the middle Geickie province of Brew and others (1978). Rocks are mainly hornfels, phyllite, semischist and marble of Paleozoic age which are cut and locally contact metamorphosed by granitic bodies of Cretaceous age. At the mineral locality, pyrite-rich epidote-garnet skarn layers are as much as 3 feet thick. Locally, chalcopyrite and arsenopyrite are present in the skarn. Massive pyrite skarn contains as much as 1100 ppm copper, 1.5 ppm silver, 0.15 ppm gold, 5000 ppm manganese and greater than 20 percent iron (Kimball and others, 1978, p. C248, location 50).
Geologic map unit	(-136.766860007316, 58.78460589459)
Mineral deposit model	Iron-copper skarn somewhat similar to Cu skarn and Fe skarn (Cox and Singer, 1986; model 18b and 18d).
Mineral deposit model number	18b and 18d
Age of mineralization	Cretaceous.
Alteration of deposit	Marble has been converted to pyritic garnet-epidote skarn.

Production and reserves

Workings or exploration	There are no mine workings; exposures limited to surface outcrops. Chip samples of pyrite-rich sulfide layers showed > 20 percent iron, from 730 to 1100 ppm copper and trace amounts of silver and gold (Kimball and others, 1978).
Indication of production	None
Additional comments Cretaceous-aged mineralization of a terrane of Paleozoic age. The area is in Glacier Bay National Park and Preserve.

References

MRDS Number	A013163
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. 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.
Reporters	C.C. Hawley (Hawley Resource Group)
Last report date	4/9/1999