Southern Wind River Range
The historic South Pass-Atlantic City and Lewiston districts are characterized by abundant small lode and placer deposits with additional potential for large-tonnage low-grade mineralization and small undiscovered high-grade deposits (Hausel, 1991). This area is a greenstone belt that forms a synclinorium of metamorphosed sedimentary, volcanic, and plutonic rocks intruded by granitic plutons. Gold mineralization occurs mainly in foliation-parallel shear zones, and is associated with quartz, sulfides, and carbonate and related wallrock alterations. Placer and paleoplacer gold deposits are widespread in the vicinity of the greenstone belt. The Oregon Buttes-Dickie Springs paleoplacers are located a few miles south of the South Pass-Atlantic City district. Love, Antweiller, and Mosier (1978) described these paleoplacers as hosting as much as 28.5 million ounces of placer gold. Interest in the South Pass-Atlantic City and Lewiston districts and adjacent placers and paleoplacers remains high – several recent exploration programs and a few small-scale mining operations have targeted these areas. An estimate by Hausel (1989) suggests that as much as 334,000 ounces of gold were mined from the South Pass-Atlantic City district.
Additional recommended WSGS publications and maps related to gold in the South Pass-Atlantic City and Lewiston areas include:
WSGS Public Information Circular 23, Tour guide to the geology and mining history of the South Pass gold mining district, Fremont County, Wyoming, by W. Dan Hausel (1984), map scale 1:24,000, large folded sheet.
WSGS Report of Investigations 44, Economic geology of the South Pass granite-greenstone belt, southern Wind River Range, western Wyoming, by W. Dan Hausel (1991), map scale 1:48,000, 129 p.
WSGS Map Series MS-70, Geologic map of the South Pass 30' x 60' Quadrangle Geologic Mapping page), by Wayne M. Sutherland, and W. Dan Hausel (2006) map scale 1:100,000, 34 p.