Flagstaff 1/sup 0/ x 2/sup 0/ NTMS area Arizona: data report (abbreviated)

Abstract

Sampling in the northern half of the quadrangle was restricted to areas outside the Hopi Indian Reservation. Surface sediment samples were collected at 977 sites, at a target sampling density of one site per 13 square kilometers. Ground water samples were collected at 45 sites in the southwestern part of the quadrangle. Neutron activation analysis results are given for uranium and 16 other elements in sediments, and for uranium and 9 other elements in ground 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 sites include: water chemistry measurements (pH, conductivity, and alkalinity); physical measurements where applicable (water temperature, well description, and scintillometer reading); and elemental analyses (U, Al, Br, Cl, Dy, F, He, Mg, Mn, Na, and V). Data from sediment sites include: stream water chemistry measurements from sites where water was available; and elemental analyses for sediment samples (U, Th, Hf, Al, Ce, Dy, Eu, Fe, La, Lu, Mn, Sc, Sm, Na, Ti, V, and Yb). Sample site descriptors are also tabulated. Areal distribution maps, histograms, and cumulative frequency plots for most elements; U/Th, U/Hf, U/(Th + Hf), and Th/La ratios; and scintillometer readings at sediment sample sites are included.Uranium concentrations in sediments of the Flagstaff quadrangle are relatively low, with a maximum value of 11 ppM. The mean of the logs of uranium values in sediments is 0.35, which corresponds to a value of about 2.2 ppM. Highest values occur in areas underlain by Quaternary volcanics and alluvium in the south-western part of the quadrangle, and in lacustrine deposits in the Hopi Buttes area on the eastern edge of the quadrangle. Both of these areas have known uranium occurrences.