Publications

Mass balance models have become standard tools for characterizing element gains and losses and volumetric change during weathering and soil development. However, they rely on the assumption of complete immobility for an index element such as Ti or Zr. Here we describe a dual-phase mass balance model that eliminates the need for an assumption of immobility and in the process quantifies...

The U.S. Geological Survey is conducting a series of multidisciplinary studies of the San Luis Basin as part of the Geologic Framework of Rio Grande Basins project. Detailed geologic mapping, high-resolution airborne magnetic surveys, gravity surveys, magnetotelluric surveys, and hydrologic and lithologic data are being used to better understand the aquifers in the San Luis Basin. This...

Sulfur, a nutrient required by terrestrial ecosystems, is likely to be regulated by atmospheric processes in well-drained, upland settings because of its low concentration in most bedrock and generally poor retention by inorganic reactions within soils. Environmental controls on sulfur sources in unpolluted ecosystems have seldom been investigated in detail, even though the possibility...

The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have not previously been characterized or interpreted. The purpose of this report is (1) to present available geochemical and petrographic data...

Samples of soil, water, mine waste leachates, soil gas, and air were collected from areas mined for mercury (Hg) and baseline sites in the Big Bend area, Texas, to evaluate potential Hg contamination in the region. Soil samples collected within 300 m of an inactive Hg mine contained elevated Hg concentrations (3.8–11 µg/g), which were considerably higher than Hg in soil collected from...

Porphyry dikes and hydrothermal veins from the porphyry Cu-Mo deposit at Butte, Montana, contain multiple generations of quartz that are distinct in scanning electron microscope-cathodoluminescence (SEM-CL) images and in Ti concentrations. A comparison of microprobe trace element profiles and maps to SEM-CL images shows that the concentration of Ti in quartz correlates positively with CL

No abstract available.

To characterize the extent and thickness of lithologic units that may have differing scour potential, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, has performed several geoelectrical surveys of the lower American River channel and flood plain between Cal Expo and the Rio Americano High School in east Sacramento, California. Additional geotechnical...

This study synthesizes available information and estimates the location and quantity of undiscovered copper associated with a late Permian bituminous shale, the Kupferschiefer, of the Southern Permian Basin in Europe. The purpose of this study is to (1) delineate permissive areas (tracts) where undiscovered reduced-facies sediment-hosted stratabound copper deposits could occur within 2.5

The lower Ohio River valley is a terraced fluvial landscape that has been profoundly influenced by Quaternary climate change and glaciation. A modern Quaternary chronostratigraphic framework was developed for the lower Ohio River valley using optically stimulated luminescence (OSL) dating and allostratigraphic mapping to gain insights into the nature of fluvial responses to glacial...

A comparison study of selected static leaching and acid–base accounting (ABA) methods using a mineralogically diverse set of 12 modern-style, metal mine waste samples was undertaken to understand the relative performance of the various tests. To complement this study, in-depth mineralogical studies were conducted in order to elucidate the relationships between sample mineralogy...

Canada and the United States collaborated in geophysical survey operations in the Amerasia Basin from 2007 to 2011 using the Canadian icebreaker CCGS Louis S. St. Laurent and the US icebreaker USCGC Healy. Over 15000 km of bathymetry, sub-bottom profiles, and 16-channel seismic reflection data were acquired over the Canada Basin and Alpha Ridge. Expendable sonobuoys were deployed to...