Unnamed (near Cony Mountain)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Au; Cu; Ni; Pd; Pt
Ore minerals chalcopyrite; pentlandite; pyrrhotite; violarite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-4
Latitude 63.29
Longitude -145.4257
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on a nunatak about 0.6 mile east-southeast of Cony Mountain. It is about 0.4 mile south of the center of section 3, T. 19 S., R. 12 E.

Geologic setting

Geologic description

Nokleberg and others (1992 [MF]; 1992 [Open-File]) map the rocks in the area as undivided gabbro, diabase, and metagabbro on their regional 1:250,000-scale geologic map. Ragan and Hawkins (1966) and Bittenbender and others (2007), who examined the geology in more detail, identified a nearly horizontal thrust fault under the occurrence. The upper plate rocks consist of highly deformed, quartz-biotite schist cut by dikes and plugs of Triassic(?) gabbro, pyroxenite, and peridotite. About 300 feet away, the schist has been intruded by Cretaceous(?) granodiorite. The mafic and ultramafic rocks are strongly altered. Peridotite is serpentinized; clinopyroxene is replaced by hornblende, biotite, and chlorite; and plagioclase is sericitized. The rocks in the lower plate are relatively undeformed basalt and fine-grained gabbro. Attempts to date the rocks were unsuccessful.
This occurrence was first identified by Bittenbender and others (2007). Most of the gabbro and peridotite samples that they collected contained at least some chalcopyrite, pyrrhotite, and pentlandite altered to violarite. They collected 6 samples; all contained at least some nickel, copper, and precious metals. The best was a 7-foot sample that contained 3,710 parts per million (ppm) nickel, 4,740 ppm copper, 385 parts per billion (ppb) platinum, 827 ppm palladium, and 340 ppb gold.
Geologic map unit (-145.427938275701, 63.289591425607)
Mineral deposit model Nickel-copper-PGE-gold mineralization possibly related to Triassic? dikes and plugs of mafic and ultramafic rocks.
Age of mineralization Unclear but may be related to Triassic(?) dikes and plugs of mafic and ultramafic rocks.
Alteration of deposit The mafic and ultramafic rocks are strongly altered. The peridotite is serpentinized; clinopyroxene is replaced by hornblende, biotite, and chlorite; and plagioclase is sericitized.

Production and reserves

Workings or exploration Only surface sampling by the Bureau of Land Management from 2001 to 2003.
Indication of production None
Reserve estimates None.
Production notes None.

References

References

Reporters D.J. Grybeck (Contractor, USGS)
Last report date 5/13/2012