A GEOCHEMICAL ATLAS OF NORTH-CAROLINA, USA

A geochemical atlas of North Carolina, U.S.A., was prepared using Nati onal Uranium Resource Evaluation (NURE) stream-sediment data, Before t ermination of the NURE program, sampling of nearly the entire state (4 8,666 square miles of land area) was completed and geochemical analyse s were obtained. The NURE data are applicable to mineral exploration, agriculture, waste disposal siting issues, health, and environmental s tudies. Applications in state government include resource surveys to a ssist mineral exploration by identifying geochemical anomalies and are as of mineralization. Agriculture seeks to identify areas with favorab le (or unfavorable) conditions for plant growth, disease, and crop pro ductivity. Trace elements such as cobalt, copper, chromium, iron, mang anese, zinc, and molybdenum must be present within narrow ranges in so ils for optimum growth and productivity. Trace elements as a contribut ing factor to disease are of concern to health professionals. Industry can use pH and conductivity data for water samples to site facilities which require specific water quality. The North Carolina NURE databas e consists of stream-sediment samples, groundwater samples, and stream -water analyses. The statewide database consists of 6,744 stream-sedim ent sites, 5,778 groundwater sample sites, and 295 stream-water sites. Neutron activation analyses were provided for U, Br, Cl, F, Mn, Na, A l, V, Dy in groundwater and stream water, and for U, Th, Hf, Ce, Fe, M n, Na, Sc, Ti, V, Al, Dy, Eu, La, Sm, Yb, and Lu in stream sediments. Supplemental analyses by other techniques were reported on U (extracta ble), Ag, As, Ba, Be, Ca, Co, Cr, Cu, K, Li, Mg, Mo, Nb, Ni, P, Pb, Se , Sn, Sr, W, Y, and Zn for 4,619 stream-sediment samples. A small subs et of 334 stream samples was analyzed for gold. The goal of the atlas was to make available the statewide NURE data with minimal interpretat ion to enable prospective users to modify and manipulate the data for their end use. The atlas provides only very general indication of geoc hemical distribution patterns and should not be used for site specific studies. The atlas maps for each element were computer-generated at t he state's geographic information system (Center for Geographic Inform ation and Analysis [ CGIA ] ). The Division of Statistics and Informat ion Services provided input files. The maps in the atlas are point map s. Each sample is represented by a symbol generally corresponding to a quartile class. Other reports will transmit sample and analytical dat a for state regions. Data are tentatively planned to be available on d isks in spreadsheet format for personal computers. During the second p hase of this project, stream-sediment samples are being assigned to st ate geologic map unit names using a GIS system to determine background and anomaly values. Subsequent publications will make this geochemica l data and accompanying interpretations available to a wide spectrum o f interdisciplinary users.