McDermitt 1/sup 0/ x 2/sup 0/ NTMS area, Nevada. Data report (abbreviated)

Abstract

Surface sediment samples were collected at 1337 sites, at a target sampling density of one site per 13 square kilometers. Ground water samples were collected at 255 sites and surface water samples were collected at 41 sites. Neutron activation analysis results are given for uranium and 16 other elements in sediments, and for uranium and 9 other elements in ground water and surface water. Mass spectrometry results are given for helium in ground water. Field measurements and observations are reported for each site. Analytical data and field measurements are presented in tables and maps. Data from ground water and surface water sites include (1) water chemistry measurements (pH, conductivity, and alkalinity), (2) physical measurements where applicable (water temperature, well description, and scintillometer reading), and (3) elemental analyses (U, Al, Br, Cl, Dy, F, Mg, Mn, Na, and V). He analyses are given for ground water. Data from sediment sites include (1) stream water chemistry measurements from sites where water was available, and (2) elemental analyses for sediment samples (U, Th, Hf, Al, Ce, Dy, Eu, Fe, La, Lu, Mn, Sc, Sm, Na, Ti, V, and Yb). Areal distribution maps, histograms, and cumulative frequency plots for most elements; U/Th, U/Hf, U/(Thmore » + Hf), and U/La ratios; and scintillometer readings at sediment sample sites are included. Uranium concentrations in sediments of the McDermitt quadrangle are relatively low, with a maximum value of 20.5 ppM. The mean of the logs of uranium values in sediments is 0.56, which corresponds to a value of about 3.6 ppM. Many of the highest uranium values occur in the Santa Rosa Range and in the Bull Run and Tuscarora Mountains. Most of the higher uranium values occur in areas underlain by tertiary-age granitic intrusive rocks and Tertiary felsic volcanic rocks. Ground water and stream water samples are too widely dispersed to allow for preliminary interpretation.« less