Geochemical mapping in Georgia, USA: a tool for environmental studies, geologic mapping and mineral exploration

Because of intensive weathering, poor exposures and thick vegetation, surfi cial geochemical mapping is a valuable tool in the southeastern United Stat es. Stream sediment and stream water geochemical data collected during the late 1970's as part of the U.S. Department of Energy's National Uranium Res ource Evaluation (NURE) Program has recently been mapped and analyzed by th e Georgia Geologic Survey with the aid of a GIS. Results indicate that bedr ock geology and mineralization are the most important variables which influ ence the stream sediment and stream water geochemistry. Anthropogenic sourc es influence the geochemistry to a lesser and more localized extent. Geoche mical mapping in Georgia has been used to define: (1) the background geoche mistry of major river basins for river basin management planning; (2) rock units which have the highest radon potential in the Piedmont and Blue Ridge ; (3) geochemical patterns that are related to regional and local geologic units and structures; and (4) geochemical anomalies related to known or pre viously unidentified mineralization. Geochemical anomalies identified and d efined by the NURE data indicate five heavy mineral belts in the Piedmont, Blue Ridge, and Coastal Plain provinces, Mississippi Valley-type mineraliza tion in the Valley and Ridge province, and base-metal (and perhaps Pt-group ) mineralization associated with mafic metavolcanic rocks, layered mafic in trusions and a regional magnetic high in the Piedmont province. (C) 1999 El sevier Science B.V. All rights reserved.