El Dorado

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale SI
Quadrangle map, 1:63,360-scale C-6
Latitude 57.5626
Longitude -135.9177
Nearby scientific data Find additional scientific data near this location
Location and accuracy The El Dorado placer occurrence is at sea level at the head of the southeast bay of Ford Arm. The prospect is 0.3 mile east of the center of sec. 3, T. 50 S., R. 59 E. It is location P-89 of Bittenbender and others (1999) and MAS no. 0021140193 (U.S. Bureau of Land Management, 2002). The location is accurate within 0.5 mile.

Geologic setting

Geologic description

Johnson and Karl (l985) map the rocks in the area of this placer prospect as Cretaceous graywacke, melange, and greenstone. The rocks are cut by numerous steeply-dipping, mainly northwest-striking faults; these include the extensions of the faults at the Hirst (SI087) and Chichagof (SI093) mines, which control the mineralization there. Bittenbender and others (1999), citing Still and Weir (1981), report that 17 panned-concentrate and stream-sediment samples contained up to 0.9 parts per million gold.
Geologic map unit (-135.919509504955, 57.5622378387319)
Mineral deposit model Placer gold (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration Only surface sampling.
Indication of production Undetermined

Additional comments

The prospect is in West Chichagof-Yakobi Wilderness.

References

References

Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p.
U.S. Bureau of Land Management, 2002, Alaska mineral locations database report (Sitka quadrangle), July 2, 2002, 205 p. [http://imcg.wr.usgs.gov/dem.html]
Reporters H.C. Berg (U.S. Geological Survey)
Last report date 10/16/2004