Unnamed (south of William Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals azurite; malachite

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale A-3
Latitude 62.1985
Longitude -142.4428
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the north flank of the large ridge bordering the south side of the valley of William and Notch Creeks. It is at an elevation of about 6,100 feet, 7,500 feet north-northwest of peak 8750, and 5,700 feet south of William Creek. The occurrence is about 0.5 mile east-southwest of the center of section 21, T. 5 N., R. 16 E. of the Copper River Meridian. It is sample locality 329 of Richter and Matson (1969) and is located to within a few hundred feet.

Geologic setting

Geologic description

This is an occurrence of secondary copper minerals localized in a breccia at the contact between granodiorite and Triassic limestone (Richter and Matson, 1969). A chip sample across 1.5 feet of the copper-stained breccia contained 2 parts per million (ppm) gold, 700 ppm boron, 7,000 ppm copper, and 700 ppm zinc. The granodiorite is along the southeast contact of the mid-Cretaceous Nabesna pluton (Richter, 1971 [I-655]; Richter, 1973; Richter, Lanphere, and Matson, 1975).
Geologic map unit (-142.444929019946, 62.1981237570897)
Mineral deposit model Contact metamorphic polymetallic deposit?
Age of mineralization Mid-Cretaceous? May be related to emplacement of the Nabesna pluton. K/Ar ages for the Nabesna pluton range from 105 +/- 4.0 to 114 +/- 3.4 Ma (Richter, Lanphere, and Matson, 1975).
Alteration of deposit Oxidation has produced secondary copper minerals.

Production and reserves

Workings or exploration Probably only surface examination.
Indication of production None

Additional comments

The occurrence is in the Wrangell-St. Elias National Preserve.

References

MRDS Number A011437

References

Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eeastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820.
Reporters Travis L. Hudson (Applied Geology)
Last report date 11/24/2002