Unnamed (northeast of Nikonda Creek) (ARDF #NB050) Au, Cu, Pb

Unnamed (northeast of Nikonda Creek)

Prospect, Inactive

Commodities and mineralogy

Main commodities	Au; Cu; Pb
Ore minerals	chalcopyrite; galena; gold; pyrite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	NB
Quadrangle map, 1:63,360-scale	A-4
Latitude	62.1803
Longitude	-142.767
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This prospect is on the west flank of the ridge northeast of Nikonda Creek. It is close to elevation 5346 and about 2,700 feet southwest of elevation 7870. The prospect is about 0.3 mile south-southwest of the center of section 26, T. 5 N., R. 14 E. of the Copper River Meridian. This is locality 4 of Richter (1973), locality 29 of Richter and others (1975), and National Park Service locality WRST-34 (unpublished data). Cobb and Richter (1980 include this locality as an 'Unnamed occurrence'. It is located to within a few hundred feet.

Geologic setting

Geologic description This prospect is a zone of intense hydrothermal alteration and brecciation in volcanic rocks of the upper Paleozoic, Tetelna Volcanics (Richter, 1973, 1976). The breccia is cemented by quartz containing minor chalcopyrite, pyrite and galena. Small unaltered to limonite-stained, porphyry intrusions cut the volcanic rocks (Richter and Matson, 1970 [OFR 70-276]). Rock samples from the area contain up to 0.9 parts per million (ppm) gold, 1,000 ppm lead, and 200 ppm copper (Richter and Matson, 1970 [OFR 70-276]).
Geologic map unit	(-142.769127459615, 62.1799100497091)
Mineral deposit model	Polymetallic veins? (Cox and Singer, 1986; model 22c)
Mineral deposit model number	22c
Age of mineralization	Cretaceous or Tertiary. The host rocks to the mineralization are late Paleozoic, but the porphyries are considered to be Tertiary (Richter, 1973, 1976). The mid-Cretaceous Nabesna pluton, spatially associated with porphyry copper deposits like that at Orange Hill (NB043), outcrops about 2 miles to the north.
Alteration of deposit	Silicification and possibly other types of alteration.

Production and reserves

Workings or exploration	At least surface prospecting has occurred at this site.
Indication of production	None
Additional comments The prospect is in the Wrangell-St. Elias National Preserve.

References

MRDS Number	A011402
References Cobb, E.H., and Richter, D.H., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Nabesna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-927, 117 p. Richter, D.H., 1976, Geologic map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-932, 1 sheet, scale 1:250,000. Richter, D.H., and Matson, N.A., Jr., 1970, Geochemical data from the Nabesna A-4 quadrangle, Alaska: U.S. Geological Survey Open-File Report 70-276, 14 p., 1 sheet, scale 1:63,360. Richter, D.H., Singer, D.A., and Cox, D.P., 1975, Mineral resources map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-655-K, 1 sheet, scale 1:250,000.
Reporters	Travis L. Hudson (Applied Geology)
Last report date	11/24/2002