NURE geochemical investigations in the Eastern United States

The Savannah River Laboratory (SRL) is conducting a hydrogeochemical and stream sediment reconnaissance of the eastern United States as part of the National Uranium Resource Evaluation (NURE) program of the United States Department of Energy (DOE). Stream samples are collected at a density of one per 13 square kilometers in crystalline rock areas and 25 square kilometers in sedimentary rock areas. Stream sediment (-40 mesh) is taken at each site, and stream water is concentrated on ion exchange resin in some areas. Ground water samples are collected at an average density of about one site per 20 square kilometers. Measurements made at each site include alkalinity, pH, and conductivity of water. Measurements of the radon and helium contents of ground water samples were made on a semiregional scale in pilot studies. Samples are analyzed at SRL by neutron activation techniques. Concentrations of uranium and about 20 other elements are determined in concentrated water samples. Results from several orientation studies are discussed including a Triassic Basin area near Sanford, North Carolina; the North and South Carolina Coastal Plain; and from reconnaissance studies in the Carolinas-Virginia Piedmont and Blue Ridge areas. In the Sanford Triassic Basin area, uranium content averaged 0.035 ppB in ground water from the organic-rich Cumnock formation and 1.8 ppB in the arkosic Pekin formation. Tuffaceous metavolcanics in the adjacent Carolina Slate Belt yielded water averaging about 0.1 ppB U. Studies in the Carolina Piedmont and Coastal Plain include helium, He/Ne and radon determinations in ground water. Background helium contents average about 5 ppM;anomalous samples range up to over twenty times background. During the next several years, an extensive data base will be established and published for elemental concentrations in stream sediment and surface and ground waters over much of the United States