Unnamed (northwest of Chistochina Glacier) (ARDF #MH285) Cu

Unnamed (northwest of Chistochina Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Cu
Other commodities	Ag; Au; Ni; Pt
Ore minerals	chalcopyrite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale	MH
Quadrangle map, 1:63,360-scale	A-2
Latitude	63.2037
Longitude	-144.8708
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is float on a moraine on the mountain northwest of the 1966 terminus of the glacier at the head of the Chistochina River. It is in the southern part of the SE1/4SE1/4 section 4, T. 20 S., R. 15 E., Fairbanks Meridian. The occurrence corresponds to locality 18 on figure 1 of Rose (1967) and locality 9 on figure 6 of Cobb (1979 [OFR 79-238]) and is included with nearby site MH284 in locality 133 on table 2 of Nokleberg and others (1991).

Geologic setting

Geologic description A dunite boulder was collected on glacial moraine near the projected contact of an ultramafic body consisting of dunite, peridotite, and pyroxenite with argillite of the Eagle Creek Formation (Rose, 1967). The ultramafic body is about 1,500 feet across and extends for about one mile, sandwiched between quartz monzonite to the south and argillite of the Eagle Creek Formation to the north. The boulder contained abundant pyrite and probably chalcopyrite and pyrrhotite; it assayed 0.75 percent copper, a trace of gold and platinum, 0.12 ounce of silver per ton, and 0.2 percent nickel (Rose, 1967). The boulder was probably derived locally.
Geologic map unit	(-144.873029695114, 63.2033045536306)
Mineral deposit model	Ni-Cu-PGE in differentiated mafic-ultramafic sill.
Age of mineralization	Probably related to ultramafic rocks of Late Triassic age.

Production and reserves

Workings or exploration	No workings are reported. The sulfide-bearing boulder was found during mapping by Rose (1967).
Indication of production	None

References

References Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mount Hayes quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-238, 140 p. Nokleberg, W.J., Lange, I.M., Roback, R.C., Yeend, Warren, and Silva, S.R., 1991, Map showing locations of metalliferous lode and placer mineral occurrences, mineral deposits, prospects, and mines, Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-C, 42 p., 1 sheet, scale 1:250,000. Rose, A.W., 1967, Geology of the upper Chistochina River area, Mount Hayes quadrangle, Alaska: Alaska Division of Mines and Minerals Geologic Report 28, 41 p., 2 maps, scale 1:40,000.
Reporters	W.T. Ellis (Alaska Earth Sciences) and C.C Hawley (Hawley Resource Group)
Last report date	7/1/2003