Unnamed (east of glacier at the head of West Fork Chistochina River) (ARDF #MH276) Au

Unnamed (east of glacier at the head of West Fork Chistochina River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Au
Other commodities	Cu; W
Ore minerals	chalcopyrite; pyrite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	MH
Quadrangle map, 1:63,360-scale	A-2
Latitude	63.2086
Longitude	-144.9181
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is about 2 miles east of the terminus of the Chistochina Glacier at an elevation of about 5,000 feet. It is in the NE1/4SW1/4 section 5, T. 20 S., R. 15 E., Fairbanks Meridian. It corresponds to locality 14 on figure 1 of Rose (1967), locality 5 on figure 6 of Cobb (1979 [OFR 78-238]), and locality 130 in table 2 of Nokleberg and others (1991). The location is probably accurate within 0.2 mile.

Geologic setting

Geologic description Argillite of the Slana Spur Formation is pyritized adjacent to a granodiorite intrusion of probable Mesozoic age (Rose, 1967). The pyritic zone is about 750 by 1,500 feet in extent. A sample of intensely iron stained argillite with a trace of chalcopyrite contained 0.04 ounce of gold per ton and a trace of silver (Rose, 1967). A sample collected during a U.S. Geological Survey investigation contained 1.2 ppm of gold, a trace of silver, and 100 ppm tungsten (Nokleberg and others, 1991).
Geologic map unit	(-144.920328038478, 63.2082030102946)
Mineral deposit model	Polymetallic vein(s) (Cox and Singer, 1986; model 22c).
Mineral deposit model number	22c
Age of mineralization	Probably related to a nearby Mesozoic intrusion.
Alteration of deposit	Pyritization of argillite adjacent to a Mesozoic granodiorite.

Production and reserves

Workings or exploration	Geologic mapping and limited surface sampling.
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), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)
Last report date	6/28/2003