Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
Water and rock geochemistry, geologic cross sections, geochemical modeling, and groundwater flow modeling for identifying the source of groundwater to Montezuma Well, a natural spring in central Arizona
The National Park Service (NPS) seeks additional information to better understand the source(s) of groundwater and associated groundwater flow paths to Montezuma Well in Montezuma Castle National Monument, central Arizona. The source of water to Montezuma Well, a flowing sinkhole in a desert setting, is poorly understood. Water emerges from the middle limestone facies of the lacustrine Verde Forma
Authors
Raymond H. Johnson, Ed DeWitt, Laurie Wirt, L. Rick Arnold, John D. Horton
Preliminary geologic map of the Cottonwood Mountain quadrangle, Iron County, Utah
No abstract available.
Authors
Florian Maldonado, John J. Anderson, Robert F. Biek
Timing, distribution, amount, and style of Cenozoic extension in the northern Great Basin
This field trip examines contrasting lines of evidence bearing on the timing and structural style of Cenozoic (and perhaps late Mesozoic) extensional deformation in northeastern Nevada. Studies of metamorphic core complexes in this region report extension beginning in the early Cenozoic or even Late Cretaceous, peaking in the Eocene and Oligocene, and being largely over before the onset of “modern
Authors
Christopher D. Henry, Allen J. McGrew, Joseph Colgan, Arthur W. Snoke, Matthew E. Brueseke
Review and interpretation of previous work and new data on the hydrogeology of the Schwartzwalder Uranium Mine and vicinity, Jefferson County, Colorado
The Schwartzwalder deposit is the largest known vein type uranium deposit in the United States. Located about eight miles northwest of Golden, Colorado it occurs in Proterozoic metamorphic rocks and was formed by hydrothermal fluid flow, mineralization, and deformation during the Laramide Orogeny. A complex brittle fault zone hosts the deposit comprising locally brecciated carbonate, oxide, and su
Authors
Jonathan S. Caine, Raymond H. Johnson, Emily C. Wild
Review of samples of sediments, tailings, and waters adjacent to the Cactus Queen Gold Mine, Kern County, California
The Cactus Queen Mine is located in the western Mojave Desert in Kern County, California. The Cactus Queen gold-silver (Au-Ag) deposit is similar to other Au-Ag deposits hosted in Miocene volcanic rocks that consist of silicic domes and associated flows, pyroclastic rocks, and subvolcanic intrusions. The volcanic rocks were emplaced onto a basement of Mesozoic silicic intrusive rocks. A part of th
Authors
James J. Rytuba, Christopher S. Kim, Daniel N. Goldstein
Isostatic gravity map of the Point Sur 30' x 60' quadrangle and adjacent areas, California
This isostatic residual gravity map is part of a regional effort to investigate the tectonics and water resources of the central Coast Range. This map serves as a basis for modeling the shape of basins and for determining the location and geometry of faults in the area. Local spatial variations in the Earth's gravity field (after removing variations caused by instrument drift, earth-tides, latitud
Authors
J. T. Watt, R. L. Morin, V. E. Langenheim
Magnetostratigraphy and tectonic rotation of the Miocene Spanish Canyon Formation at Alvord Mountain, California
No abstract available.
Authors
John W. Hillhouse, David M. Miller
ATV magnetometer systems for efficient ground magnetic surveying
Ground magnetic data contain information, not pre-sent in aeromagnetic data, which may be useful for precisely mapping near-surface faults and contacts, as well as constraining or aiding interpretation of other geophysical methods. However, collecting ground magnetic data on foot is labor-intensive and is therefore limited to small surveys. In this article, we present two newly developed all-terra
Authors
Noah D. Athens, Jonathan M. G. Glen, Robert L. Morin, Simon L. Klemperer
Three-dimensional geologic model of the southeastern Espanola Basin, Santa Fe County, New Mexico
This multimedia model and report show and describe digital three-dimensional faulted surfaces and volumes of lithologic units that confine and constrain the basin-fill aquifers within the Espanola Basin of north-central New Mexico. These aquifers are the primary groundwater resource for the cities of Santa Fe and Espanola, six Pueblo nations, and the surrounding areas. The model presented in this
Authors
Michael P. Pantea, Mark R. Hudson, V. J. S. Grauch, Scott A. Minor
A refined characterization of the alluvial geology of yucca flat and its effect on bulk hydraulic conductivity
In Yucca Flat, on the Nevada National Security Site in southern Nevada, the migration of radionuclides from tests located in the alluvial deposits into the Paleozoic carbonate aquifer involves passage through a thick, heterogeneous section of late Tertiary and Quaternary alluvial sediments. An understanding of the lateral and vertical changes in the material properties of the alluvial sediments wi
Authors
G. A. Phelps, K. J. Halford
Vadose zone controls on weathering intensity and depth: Observations from grussic saprolites
An investigation of vadose zone weathering processes has been undertaken on grussic saprolites developed on Californian granitoids. Preliminary results indicate strong climatic control, through infiltration, on the depth and intensity of weathering. At sites with higher infiltration, the vadose zone is comprehensively altered to grussic saprolite and saprock. Conversely, lower infiltration sites d
Authors
B. W. Goodfellow, G.E. Hilley, Marjorie S. Schulz
Self-potential investigations of a gravel bar in a restored river corridor
Self-potentials (SP) are sensitive to water fluxes and concentration gradients in both saturated and unsaturated geological media, but quantitative interpretations of SP field data may often be hindered by the superposition of different source contributions and time-varying electrode potentials. Self-potential mapping and close to two months of SP monitoring on a gravel bar were performed to inve
Authors
N. Linde, J. Doetsch, D. Jougnot, O. Genoni, Y. Durst, Burke J. Minsley, T. Vogt, N. Pasquale, J. Luster