Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2350
Structural development of high-temperature mylonites in the Archean Wyoming province, northwestern Madison Range, Montana
The Crooked Creek mylonite, in the northwestern Madison Range, southwestern Montana, is defined by several curved lenses of high non-coaxial strain exposed over a 7-km-wide, northeast-trending strip. The country rocks, part of the Archean Wyoming province, are dominantly trondhjemitic to granitic orthogneiss with subordinate amphibolite, quartzite, aluminous gneiss, and sills of metabasite (mafic
Authors
Karl S. Kellogg, David W. Mogk
Aeromagnetic survey of Howard Pass quadrangle and the East half of Misheguk Mountain quadrangle, Alaska—a Web site for the distribution of data
U.S. Geological Survey Open-File-Report 2009-1256 is for the preliminary release of magnetic data (and associated contractor reports) for an airborne survey in the Brooks Range, northwest of Bettles, Alaska.
Authors
Philip J. Brown
Revisions to the stratigraphic nomenclature of the Abiquiu Formation, Abiquiu and contiguous areas, north-central New Mexico
Stratigraphic studies and geologic mapping on the Abiquiu 7.5-min quadrangle have led to revision of the stratigraphic nomenclature for the Oligocene to Miocene Abiquiu Formation in north-central New Mexico. The Abiquiu Formation had previously been defined to include informal upper, middle (Pedernal chert member), and lower members. The basement-derived conglomeratic lower member in the northern
Authors
Florian Maldonado, Shari A. Kelley
Effects of experimental protocol on global vegetation model accuracy: a comparison of simulated and observed vegetation patterns for Asia
Prognostic vegetation models have been widely used to study the interactions between environmental change and biological systems. This study examines the sensitivity of vegetation model simulations to: (i) the selection of input climatologies representing different time periods and their associated atmospheric CO2 concentrations, (ii) the choice of observed vegetation data for evaluating the model
Authors
Guoping Tang, Sarah L. Shafer, Patrick J. Barlein, Justin O. Holman
Paleomagnetism of Miocene volcanic rocks in the Newberry Mountains, California: Vertical-axis rotation and a polarity transition
No abstract available.
Authors
J. W. Hillhouse, R. E. Wells, B. F. Cox
New approaches to stability analysis of steep coastal bluffs
We present a discussion on the limitations and needed improvements for existing slope stability analysis methods to accurately model steep coastal bluff failures resulting from both direct wave action at the toe in weakly cemented sands and precipitation-induced seepage failures in moderately cemented sands. Using a case-study detailing over 5 years of observations of coastal bluff erosion and lan
Authors
Brian D. Collins, Nicholas Sitar
Cenozoic evolution of the abrupt Colorado Plateau–Basin and Range boundary, northwest Arizona: A tale of three basins, immense lacustrine-evaporite deposits, and the nascent Colorado River
In northwest Arizona, the relatively unextended Colorado Plateau gives way abruptly to the highly extended Colorado River extensional corridor within the Basin and Range province along a system of major west-dipping normal faults, including the Grand Wash fault zone and South Virgin–White Hills detachment fault. Large growth-fault basins developed in the hanging walls of these faults. Lowering of
Authors
J. E. Faulds, Keith A. Howard, E. M. Duebendorfer
Linking soil organic matter dynamics and erosion-induced terrestrial carbon sequestration at different landform positions
Recently, the potential for terrestrial carbon (C) sequestration by soil erosion and deposition has received increased interest. Erosion and deposition constitute a sink for atmospheric carbon dioxide relative to a preerosional state or a noneroding scenario, if the posterosion watershed C balance is increased due to (1) partial replacement of eroded C by new photosynthate in the eroded site; and
Authors
Asmeret Asefaw Berhe, Jennifer W. Harden, Margaret S. Torn, John Harte
Temporal Geochemistry Data from Five Springs in the Cement Creek Watershed, San Juan County, Colorado
Temporal data from five springs in the Cement Creek watershed, San Juan County, Colorado provide seasonal geochemical data for further research in the formation of ferricretes. In addition, these data can be used to help understand the ground-water flow system. The resulting data demonstrate the difficulty in gathering reliable seasonal data from springs, show the unique geochemistry of each sprin
Authors
Raymond H. Johnson, Laurie Wirt, Kenneth J. Leib
Origin of meter-size granite basins in the southern Sierra Nevada, California
Meter-size granite basins are found in a 180-km belt extending south from the South Fork of the Kings River to Lake Isabella on the west slope of the southern Sierra Nevada, California. Their origin has long been debated. A total of 1,033 basins have been inventoried at 221 sites. The basins occur on bedrock granitic outcrops at a median elevation of 1,950 m. Median basin diameter among 30 of the
Authors
James G. Moore, Mary A. Gorden, Joel E. Robinson, Barry C. Moring
Analytical Results for Municipal Biosolids Samples from a Monitoring Program near Deer Trail, Colorado (U.S.A.), 2007
Since late 1993, the Metro Wastewater Reclamation District of Denver (Metro District), a large wastewater treatment plant in Denver, Colorado, has applied Grade I, Class B biosolids to about 52,000 acres of nonirrigated farmland and rangeland near Deer Trail, Colorado (U.S.A.). In cooperation with the Metro District in 1993, the U.S. Geological Survey (USGS) began monitoring ground water at part o
Authors
J. G. Crock, D. B. Smith, T. J. B. Yager, C. J. Berry, M. G. Adams
Boreal soil carbon dynamics under a changing climate: A model inversion approach
Several fundamental but important factors controlling the feedback of boreal organic carbon (OC) to climate change were examined using a mechanistic model of soil OC dynamics, including the combined effects of temperature and moisture on the decomposition of OC and the factors controlling carbon quality and decomposition with depth. To estimate decomposition rates and evaluate their variations wit
Authors
Zhaosheng Fan, Jason C. Neff, Jennifer W. Harden, Kimberly P. Wickland