Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2350
Mesozoic magmatism and timing of epigenetic Pb-Zn-Ag mineralization in the western Fortymile mining district, east-central Alaska: Zircon U-Pb geochronology, whole-rock geochemistry, and Pb isotopes
The Mesozoic magmatic history of the North American margin records the evolution from a more segmented assemblage of parautochthonous and allochthonous terranes to the more cohesive northern Cordilleran orogenic belt. We characterize the setting of magmatism, tectonism, and epigenetic mineralization in the western Fortymile mining district, east-central Alaska, where parautochthonous and allochtho
Authors
Cynthia Dusel-Bacon, J.N. Aleinkoff, W. C. Day, J.K. Mortensen
Seismotectonic significance of the 2008–2010 Walloon Brabant seismic swarm in the Brabant Massif, Belgium
Between 12 July 2008 and 18 January 2010 a seismic swarm occurred close to the town of Court-Saint-Etienne, 20 km SE of Brussels (Belgium). The Belgian network and a temporary seismic network covering the epicentral area established a seismic catalogue in which magnitude varies between ML -0.7 and ML 3.2. Based on waveform cross-correlation of co-located earthquakes, the spatial distribution of th
Authors
Koen Van Noten, Thomas Lecocq, Anjana K. Shah, Thierry Camelbeeck
Potential metal recovery from waste streams
‘Waste stream’ is a general term that describes the total flow of waste from homes, businesses, industrial facilities, and institutions that are recycled, burned or isolated from the environment in landfills or other types of storage, or dissipated into the environment. The recovery and reuse of chemical elements from waste streams have the potential to decrease U.S. reliance on primary resources
Authors
Kathleen S. Smith, Philip L. Hageman, Geoffrey S. Plumlee, James R. Budahn, Donald I. Bleiwas
Comparing activated alumina with indigenous laterite and bauxite as potential sorbents for removing fluoride from drinking water in Ghana
Fluoride is considered beneficial to teeth and bones when consumed in low concentrations, but at elevated concentrations it can cause dental and skeletal fluorosis. Most fluoride-related health problems occur in poor, rural communities of the developing world where groundwater fluoride concentrations are high and the primary sources of drinking water are from community hand-pump borehole drilled w
Authors
Laura Craig, Lisa L. Stillings, David L. Decker, James M. Thomas
What lies beneath: geophysical mapping of a concealed Precambrian intrusive complex along the Iowa–Minnesota border
Large-amplitude gravity and magnetic highs over northeast Iowa are interpreted to reflect a buried intrusive complex composed of mafic–ultramafic rocks, the northeast Iowa intrusive complex (NEIIC), intruding Yavapai province (1.8–1.72 Ga) rocks. The age of the complex is unproven, although it has been considered to be Keweenawan (∼1.1 Ga). Because only four boreholes reach the complex, which is c
Authors
Benjamin J. Drenth, Raymond R. Anderson, Klaus J. Schulz, Joshua M. Feinberg, Val W. Chandler, William F. Cannon
Antimony: a flame fighter
Antimony is a brittle, silvery-white semimetal that conducts heat poorly. The chemical compound antimony trioxide (Sb2O3) is widely used in plastics, rubbers, paints, and textiles, including industrial safety suits and some children’s clothing, to make them resistant to the spread of flames. Also, sodium antimonate (NaSbO3) is used during manufacturing of high-quality glass, which is found in cell
Authors
Niki E. Wintzer, David E. Guberman
Rhenium: a rare metal critical in modern transportation
Rhenium is a silvery-white, metallic element with an extremely high melting point (3,180 degrees Celsius) and a heat-stable crystalline structure, making it exceptionally resistant to heat and wear. Since the late 1980s, rhenium has been critical for superalloys used in turbine blades and in catalysts used to produce lead-free gasoline.
One of the rarest elements, rhenium has an average abundance
Authors
David John
11.12 – Tools and techniques: gravitational method
The gravitational method is used to investigate density variations within the subsurface at depths of several meters to tens of meters, as in depth-to-bedrock investigations, or at depths of several kilometers, as in sedimentary basin thickness investigations. This chapter covers fundamental relations, densities of Earth materials, instruments, field procedures, data reduction, filtering, forward
Authors
Jeffrey Phillips
Physical subdivision and description of the water-bearing sediments of the Santa Clara Valley, California
A thick Quaternary alluvial section fills a sedimentary basin beneath the Santa Clara Valley, California, located within the San Andreas Fault system at the south end of San Francisco Bay. This section consists of an upper sequence about 1,000 feet thick containing eight sedimentary cycles and a lower fine-grained unit as thick as several hundred feet. Together these constitute the Quaternary Sant
Authors
Carl M. Wentworth, Robert C. Jachens, Robert A. Williams, John C. Tinsley, Randall T. Hanson
Expanding metal mixture toxicity models to natural stream and lake invertebrate communities
A modeling approach that was used to predict the toxicity of dissolved single and multiple metals to trout is extended to stream benthic macroinvertebrates, freshwater zooplankton, and Daphnia magna. The approach predicts the accumulation of toxicants (H, Al, Cd, Cu, Ni, Pb, and Zn) in organisms using 3 equilibrium accumulation models that define interactions between dissolved cations and biologic
Authors
Laurie S. Balistrieri, Christopher A. Mebane, Travis S. Schmidt, William (Bill) Keller
Variables and potential models for the bleaching of luminescence signals in fluvial environments
Luminescence dating of fluvial sediments rests on the assumption that sufficient sunlight is available to remove a previously obtained signal in a process deemed bleaching. However, luminescence signals obtained from sediment in the active channels of rivers often contain residual signals. This paper explores and attempts to build theoretical models for the bleaching of luminescence signals in flu
Authors
Harrison J. Gray, Shannon Mahan
Impacts of climate change on the formation and stability of late Quaternary sand sheets and falling dunes, Black Mesa region, southern Colorado Plateau, USA
Detailed geomorphic mapping and analysis of soil-stratigraphy and optically stimulated luminescence (OSL) dating of eolian sand dunes on Black Mesa, Arizona, reveal eolian sediment deposition occurred from 30 to 16 ka, followed by a period of widespread dune stabilization from 12 to 8 ka. Localized reactivation of the previously stabilized dune forms or local changes in sediment supply have occurr
Authors
Amy L. Ellwein, Shannon Mahan, Leslie D. McFadden