Erie (ARDF #NB075) Ag, Au, Pb

Erie

Prospect, Inactive

Commodities and mineralogy

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

Geographic location

Quadrangle map, 1:250,000-scale	NB
Quadrangle map, 1:63,360-scale	A-2
Latitude	62.0809
Longitude	-141.8674
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This prospect is on lower Bonanza Creek about 2,000 feet upstream of its mouth. The site is in the SE1/4 of section 35, T. 4 N., R. 19 E. of the Copper River Meridian. This is locality 42 of Richter and others (1975) and the site is included in National Park Service locality WRST-62 (unpublished data). Cobb and Richter (1980) included this prospect under the name 'Erie'. It is located to within a few hundred feet.

Geologic setting

Geologic description At this prospect, Cretaceous volcanic and volcaniclastic rocks contain disseminated pyrite; the rocks are locally cut by pyrite-bearing dikes (Moffit, 1943; Richter and Jones, 1973). Small pyrite and quartz veins in volcanic rock and in a dike that strikes N 20 W and dips 75 N contain free gold and galena with up to 22 ounces silver per ton (Capps, 1916). A grab sample of massive, green fragmental volcanic rock contained 1,500 parts per million (ppm) copper and 500 ppm lead (Richter and Matson, 1970 [OFR 70-275]). Short adits have been driven to explore this prospect. This mineralized zone is on the southeast flank of Gold Hill, where intrusive rocks of the Chisana pluton intrude volcanic rocks of the Cretaceous, Chisana Formation.
Geologic map unit	(-141.869530057819, 62.0805377314687)
Mineral deposit model	Polymetallic veins? (Cox and Singer,1986; model 22c)
Mineral deposit model number	22c?
Age of mineralization	Mid-Cretaceous? The deposit may be related to emplacement of the Chisana pluton which has a K/Ar age of 110 +/- 3.0 Ma (Richter, Lanphere, and Matson, 1975).
Alteration of deposit	Disseminated pyrite and quartz-sulfide veining. Oxidation has produced iron-staining.

Production and reserves

Workings or exploration	This altered and mineralized zone has been explored by surface prospecting and short adits.
Indication of production	Undetermined
Additional comments The prospect is in the Wrangell-St. Elias National Preserve.

References

MRDS Number	A011413
References Capps, S.R., 1916, The Chisana-White River district, Alaska: U.S. Geological Survey Bulletin 630, 130 p. 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. Moffit, F.H., and Wayland, R.G., 1943, Geology of the Nutzotin Mountains, Alaska, with a section on The igneous rocks: U.S. Geological Survey Bulletin 933-B, p. 103-199. Richter, D.H., and Jones, D.L., 1973, Reconnaissance geologic map of the Nabesna A-2 quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-749, 1 sheet, scale 1:63,360. Richter, D.H., and Matson, N.A., Jr., 1970, Geochemical data from the Nabesna A-2 quadrangle, Alaska: U.S. Geological Survey Open-File Report 70-275, 12 p., 1 sheet, scale 1:63,360. Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eeastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820. 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