Unnamed (near terminus of Casement Glacier) (ARDF #JU015) Cu

Unnamed (near terminus of Casement Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu
Ore minerals	pyrite

Geographic location

Quadrangle map, 1:250,000-scale	JU
Quadrangle map, 1:63,360-scale	D-6
Latitude	58.9242
Longitude	-135.9639
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is at an elevation of about 300 feet, approximately 3.5 miles southwest of Snow Dome and 3 miles north of Adams Inlet. It is near the terminus of Casement Glacier in the NE1/4 section 18, T. 34 S., R. 57 E. of the Copper River Meridian. The location is accurate within 1/4 mile.

Geologic setting

Geologic description The rocks in the vicinity of this occurrence are predominantly Silurian and Devonian graywacke and argillite, and nonfoliated, Tertiary felsic granitic rocks and migmatite. Foliated, Cretaceous intermediate granitic plutons and migmatite crop out south of the occurrence (Brew and others, 1978). At the occurrence, altered zones 5 to 30 feet thick cut granitic rock near hornfels at the contact. The altered zones contain pyrite. A composite sample of altered rock contained 500 ppm copper and 5 ppm molybdenum (MacKevett and others, 1971). The rocks in the vicinity of this occurrence are deformed and metamorphosed Silurian or Devonian carbonate, clastic and volcanic clastic rocks that have been intruded by Upper Jurassic and Lower Cretaceous granitic and dioritic rocks (Brew and others, 1992).
Geologic map unit	(-135.965780629052, 58.9238132295208)
Age of mineralization	Tertiary.
Alteration of deposit	Hornfelsing and iron-staining.

Production and reserves

Indication of production	None

References

MRDS Number	A012079
References Brew, D.A., Himmelberg, G.R., Loney, R.A., and Ford, A.B., 1992, Distribution and characteristics of metamorphic belts in the southeastern Alaska part of the North American Cordillera--Metamorphic styles in young and ancient orogenic belts: Journal of Metamorphic Geology, v. 10, no. 3, p. 465-482. 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. 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.
Reporters	J.C. Barnett and L.D. Miller (Juneau, Alaska )
Last report date	12/15/2001