Eagle River (ARDF #AN113) Ag, Au, Cu, Pb, Zn

Eagle River

Prospect, Inactive

Alternative names

Mayflower

Commodities and mineralogy

Main commodities	Ag; Au; Cu; Pb; Zn
Ore minerals	argentiferous galena; arsenopyrite; chalcopyrite; gold; malachite; pyrite; sphalerite
Gangue minerals	calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale	AN
Quadrangle map, 1:63,360-scale	A-6
Latitude	61.13
Longitude	-149.09
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	Prospect located near the south bank of Eagle River, 4,500 ft west-northwest of the terminus of Eagle Glacier. Accurate within 2,000 ft. Locality 7 on plate 33 of Park (1933), locality 51 of Cobb (1972), and locality 40 of MacKevett and Holloway (1977).

Geologic setting

Geologic description Mineralized quartz veins in fine-grained, massive metagraywacke of the Late Cretaceous Valdez Group. The host rock shows sheared zones that strike N 5 W and are vertical or dip about 65 NW. Several large interbedded conglomerate lenses and minor argillite are present within the graywacke. Mineralized quartz veins that are less than 1 ft thick and that can be traced for 400 ft, are found in two sheared zones 50 ft apart (Park, 1933). Quartz veins contain galena, pyrite, sphalerite, arsenopyrite, chalcopyrite, and limited malachite. Assays show 0.05 oz/ton Au and 10 to 25 oz/ton Ag (Park, 1933). Calcite veinlets found in joints of graywacke (Martin and others, 1915). The most conspicuous quartz vein can be traced south of the river and probably is also exposed to the north of Eagle River.
Geologic map unit	(-149.09219995551, 61.1294433376686)
Mineral deposit model	Low-sulfide Au-quartz veins? (Cox and Singer, 1986; model 36a?) or Chugach-type low-sulfide Au-quartz vein? (Bliss, 1992; model 36a.1?) or Polymetallic veins? (Cox and Singer, 1986; model 22c?).
Mineral deposit model number	36a, 36a.1, 22c
Age of mineralization	Late Cretaceous or younger; the veins cut Late Cretaceous Valdez Group rocks.
Alteration of deposit	Oxidation of Cu minerals.

Production and reserves

Workings or exploration	Assays show 0.05 oz/ton Au and 10 to 25 oz/ton Ag (Park, 1933). Limited amount of work on prospect by 1933. Smith (1938) reported prospecting in 1936, a vein opened by a few open cuts with apparently encouraging results. By 1951 the prospect could not be found (White, 1952).
Indication of production	None
Additional comments Property originally known as the Mayflower lode (Park, 1933).

References

MRDS Number	A011652
References Berg, H.C., and Cobb, E.H., 1967, Metalliferous lode deposits of Alaska: U.S. Geological Survey Bulletin 1246, 254 p. Capps, S.R., 1916, Gold mining in the Willow Creek district: U.S. Geological Survey Bulletin 642-G, p. 147-194, 195-200. Clark, S.H.B., 1972, Reconnaissance bedrock geologic map of the Chugach Mountains near Anchorage, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map 350, 1 sheet, scale 1:250,000. Clark, S.H.B., and Yount, M.E., 1972, Reconnaissance geologic map and geochemical analyses of stream-sediment and rock samples of the Anchorage A-6 Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map 351, 2 sheets, scale 1:63,360. Cobb, E.H., 1972, Metallic mineral resources map of the Anchorage Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map 409, 1 sheet, scale 1:250,000. Jansons, U., Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, Southcentral Alaska: U.S. Bureau of Mines Open-File Report 5-84, 218 p., 2 sheets, scale 1:250,000. Martin G.C., Johnson, B.L., and Grant, U.S., 1915, Geology and mineral resources of Kenai Peninsula, Alaska: U.S. Geological Survey Bulletin 587, 243 p. Park, F.C., 1933, The Girdwood District, Alaska: U.S. Geological Survey Bulletin 849-G, p. 381-424. Smith, P.S., 1938, Mineral industry of Alaska in 1936: U.S. Geological Survey Bulletin 897-A, p. 1-107. White, M.G., 1952, Preliminary summary of reconnaissance for uranium in Alaska, 1951: U.S. Geological Survey Circular 196, 17 p.
Reporters	D.P. Bickerstaff (USGS contractor); S.W. Huss (USGS)
Last report date	7/30/1998