Unnamed (north of mouth of York Creek) (ARDF #JU072) Co, Cu, Ni

Unnamed (north of mouth of York Creek)

Prospect, Inactive

Commodities and mineralogy

Main commodities	Co; Cu; Ni
Other commodities	Au
Ore minerals	pyrite; pyrrhotite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	JU
Quadrangle map, 1:63,360-scale	C-6
Latitude	58.6477
Longitude	-135.9188
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This prospect is at an elevation of approximately 100 feet, 0.5 mile north-northwest of the mouth of York Creek It is just east of the center of section 24, T. 37 S., R. 57 E. of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description The general area is underlain by 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). This deposit was discovered in 1899. It is in hornfels, and consists of 5 widely-spaced, pyrite-rich quartz veins and of altered zones that contain pods of pyrite. The veins are up to 0.5 foot thick, and the altered zones are up to 50 feet thick. A nearby, half-mile-long, iron-stained zone in siliceous limestone contains 5-10% pyrrhotite (Brew and others, 1978). A select grab sample of one of the quartz veins contained 1,500 ppm copper, 150 ppm cobalt, 150 ppm nickel, and a trace of gold (MacKevett and others, 1971).
Geologic map unit	(-135.920663458883, 58.6473374760434)
Alteration of deposit	Conspicuous iron-stained zone.

Production and reserves

Workings or exploration	Surface sampling only.
Indication of production	None

References

MRDS Number	A012095
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