Publications

Computer programs were written in the Fortran language to process and display gravity data with locations expressed in geographic coordinates. The programs and associated processes have been tested for gravity data in an area of about 125,000 square kilometers in northwest Nevada, southeast Oregon, and northeast California. This report discusses the geographic aspects of data processing

For the last several years, Montana has been the leading talc producing state in the United States (U.S. Geological Survey, 1996). For example, in 1992 Montana supplied about 40 percent of the U.S. mine production of talc (Virta, 1992). All of this production has come from the large deposits of high purity talc in the southwestern part of the state. All Montana talc is currently (1997)...

The Thermal Emission Spectrometer spectra of low albedo surface materials suggests that a four to one mixture of pyroxene to plagioclase, together with about a 35 percent dust component provides the best fit to the spectrum. Qualitative upper limits can be placed on the concentration of carbonates (

This report presents porewater and selected water column data collected from Coeur d'Alene Lake in September of 1992. Despite probable oxidation of the porewater samples during collection and handling, these data are used to calculate molecular diffusive fluxes of dissolved metals (that is, Zn, Pb, Cu, and Mn) across the sediment-water interface. While these data and calculations provide

We present evidence for several non‐ice constituents in the surface material of the icy Galilean satellites, using the reflectance spectra returned by the Galileo near infrared mapping spectrometer (NIMS) experiment. Five new absorption features are described at 3.4, 3.88, 4.05, 4.25, and 4.57 μm for Callisto and Ganymede, and some seem to exist for Europa as well. The four absorption...

The U.S. Geological Survey is conducting research on the impacts of produced waters on petroleum resource development and the environment. Ongoing multidisciplinary investigations are focused on the 1) quantity and quality of current water production, 2) geologic and geochemical parameters that influence the viability of injection wells, and 3) processes that affect the dispersion of...

Calcite is ubiquitous at Yucca Mountain, occurring in the soils and as fracture and cavity coatings within the volcanic tuff section. Strontium is a trace element in calcite, generally at the tens to hundreds of ppm level. Because calcite contains very little rubidium and the half-life of the 87Rb parent is billions of years, the 87Sr/86Sr ratios of the calcite record the ratio in the...

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Molybdenum (Mo) is an essential element for many plants and animals (Newton and Otsuka, 1980). Because of its chemical properties, Mo readily provides sites for reactions and catalysis in biochemical systems (Haight and Boston, 1973). It is therefore important to understand the processes that control the distribution, speciation, and behavior of Mo in the surficial environment. These...

Since the first studies of sulfur isotope variations in natural materials (Thode, 1949), it has been apparent that there are large and dramatic variations of 34S/32S ratios and that sulfur isotope studies are a powerful tool for interpreting the origins of sulfur-bearing minerals. However, sulfur is such a common element in the Earth's crust (sixteenth most abundant, averaging 0.03 wt %...