MINERALOGY AND ORIGIN OF THE TALC DEPOSITS NEAR WINTERBORO, ALABAMA

The north and south talc bodies near Winterboro, Alabama, are associated with Cambrian dolomite. The north body lies like a blanket in residual clay which overlies the dolomite bedrock, and the lense-shaped south body is oriented along a fracture in the dolomite with a strike of N 65° W and a dip of 43° NE. The nature and distribution of insoluble residues in the dolomite as well as textural and field evidence suggest that hydrothermal solutions and metasomatic processes produced talc in and near fractures in the dolomite. These solutions are apparently also responsible for the production of chlorite in the dolomite and in associated shales and sandstones, or chlorite metasoma-tites, beneath the south body. Weathering exposed the north body and part of the south body and produced brecciation and siltcification as well as a residuum of talc and chlorite in the vicinity of the orebodies. Insoluble residues in dolomite obtained from diamond drill cores suggest that a mineralized halo of talc and chlorite extends at least 200 feet from the main orebody, with the talc to chlorite ratio increasing as the talc body is approached. This feature, the presence of talc in the residual soils overlying the dolomite, and the associated chlorite and chlorite metasomatites may be useful in prospecting for Winterboro-type talc deposits. © 1980 Society of Economic Geologists, Inc.