Unnamed (on hill 4890 east of VABM Keg)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Cu
Ore minerals azurite; chalcocite; malachite

Geographic location

Quadrangle map, 1:250,000-scale GU
Quadrangle map, 1:63,360-scale D-5
Latitude 62.791
Longitude -146.205
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence is near the crest of hill 4890 about 2.5 miles east of VABM Keg. It is in the NE1/4SW1/4, section 29, T. 12 N., R. 5 W., Copper River Meridian. The occurrence is located accurately within 1000 feet.

Geologic setting

Geologic description

The occurrence is in schistose, andesitic to basaltic, volcanic rocks, tentatively correlated with the Pennsylvanian to Permian, Tetelna Formation. Numerous occurrences of chalcocite partly oxidized to azurite and malachite occur in the section (Arehart, 1982, p. 3). This locality is Arehart's sample 2308 which contained more than 2 percent copper and 50 ppm silver. The sample was high-grade material; there are also probably numerous additional small copper occurrences in the vicinity.
Geologic map unit (-146.207223097187, 62.7905625236268)
Mineral deposit model Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Mineral deposit model number 24a
Age of mineralization Remobilization of copper may have occurred during greenschist metamorphism in the Jurassic(?).
Alteration of deposit Local introduction of epidote.

Production and reserves

Workings or exploration The occurrence was found in 1981 during regional reconnaissance by Noranda Inc. on Ahtna Inc., Regional Native Corporation lands.
Indication of production None

Additional comments

Outcrops are mostly limited to ridge crests; hill slopes below about 3,500 feet in elevation are mostly covered with gravel and have thick brush mats. Additional information can be obtained from Ahtna Minerals in Anchorage, Alaska.

References

MRDS Number 10307475

References

Arehart, G.B., 1982, Reconnaissance geology/geochemistry of the Alphabet Hills, Gulkana quadrangle, Alaska: Noranda Exploration, 4 p., maps and appendices. (Report held by Ahtna Minerals Co., Anchorage, Alaska).
Reporters W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (U.S. Geological Survey)
Last report date 12/20/2000