Exploration geochemistry: The Los Alamos experience

Los Alamos National Laboratory became actively involved in geochemical exploration in 1975 by conducting a reconnaissance-scale exploration program for uranium as part of the National Uranium Resource Evaluation program. Initially, only uranium and thorium were analyzed. By 1979 Los Alamos was analyzing a multielement suite. The data were presented in histograms and as black and white concentration plots for uranium and thorium only. Data for the remaining elements were presented as hard copy data listings in an appendix to the report. In 1983 Los Alamos began using exploration geochemistry for the purpose of finding economic mineral deposits to help stimulate the economies of underdeveloped countries. Stream-sediment samples were collected on the Caribbean island of St. Lucia and a geochemical atlas of that island was produced. The data were statistically smoothed and presented as computer-generated color plots of each element of the multielement suite. Studies for the US Bureau of Land Management in 1984 consisted of development of techniques for the integration of several large data sets, which could then be used for computer-assisted mineral resource assessments. A supervised classification technique was developed which compares the attributes of grid cells containing mines or mineral occurrences with attributes of unclassified cells not more » known to contain mines or occurrences. Color maps indicate how closely unclassified cells match in attributes the cells with mines or occurrences. 20 refs., 1 fig., 1 tab. « less