Publications
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Magmatism, metasomatism, tectonism, and mineralization in the Humboldt Range, Pershing County, Nevada
Introduction
The Humboldt Range, Pershing County, Nevada, predominantly consists of Mesozoic igneous and sedimentary rocks that were modified several times by magmatism, metasomatism, and tectonism, and contain a variety of metallic (Ag, Au, Pb, Zn, Sb, W, Hg) and non-metallic (dumortierite, pinite, fluorite) mineral deposits (Knopf, 1924; Kerr and Jenney, 1935; Kerr, 1938; Cameron, 1939; Campbe
Authors
Peter G. Vikre
Lateritic, supergene rare earth element (REE) deposits
Intensive lateritic weathering of bedrock under tropical or sub-tropical climatic conditions can form a variety of secondary, supergene-type deposits. These secondary deposits may range in composition from aluminous bauxites to iron and niobium, and include rare earth elements (REE). Over 250 lateritic deposits of REE are currently known and many have been important sources of REE. In southeastern
Authors
Mark D. Cocker
Potash: a global overview of evaporate-related potash resources, including spatial databases of deposits, occurrences, and permissive tracts
Potash is mined worldwide to provide potassium, an essential nutrient for food crops. Evaporite-hosted potash deposits are the largest source of salts that contain potassium in water-soluble form, including potassium chloride, potassium-magnesium chloride, potassium sulfate, and potassium nitrate. Thick sections of evaporitic salt that form laterally continuous strata in sedimentary evaporite basi
Authors
Greta J. Orris, Mark D. Cocker, Pamela Dunlap, Jeff C. Wynn, Gregory T. Spanski, Deborah A. Briggs, Leila Gass, James D. Bliss, Karen S. Bolm, Chao Yang, Bruce R. Lipin, Stephen Ludington, Robert J. Miller, Mirosław Słowakiewicz
Gravity survey and interpretation of Fort Irwin and vicinity, Mojave Desert, California
In support of a hydrogeologic study of the groundwater resources on Fort Irwin, we have combined new gravity data with preexisting measurements to produce an isostatic residual gravity map, which we then separated into two components reflecting (1) the density distribution in the pre-Cenozoic basement complex and (2) the distribution of low-density Cenozoic volcanic and sedimentary deposits that l
Authors
Robert C. Jachens, Victoria E. Langenheim
Introduction to the geologic and geophysical studies of Fort Irwin, California
Geologic and geophysical investigations in the vicinity of Fort Irwin National Training Center, California, have been completed in support of groundwater investigations, and are presented in eight chapters of this report. A generalized surficial geologic map along with field and borehole investigations conducted during 2010–11 provide a lithostratigraphic and structural framework for the area duri
Authors
David C. Buesch
Generalized surficial geologic map of the Fort Irwin Area, San Bernardino County, California
The geology and landscape of the Fort Irwin area, typical of many parts of the Mojave Desert, consist of rugged mountains separated by broad alluviated valleys that form the main coarse-resolution features of the geologic map. Crystalline and sedimentary rocks, Mesozoic and older in age, form most of the mountains with lesser accumulations of Miocene sedimentary and volcanic rocks. In detail, the
Authors
David M. Miller, Christopher M. Menges, David J. Lidke
By
Energy and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Aeromagnetic data, processing, and maps of Fort Irwin and vicinity, California
Aeromagnetic data help provide the underpinnings of a hydrogeologic framework for Fort Irwin by locating inferred structural features or grain that influence groundwater flow. Magnetization boundaries defined by horizontal-gradient analyses coincide locally with Cenozoic faults and can be used to extend these faults beneath cover. These boundaries also highlight the structural grain within the cry
Authors
Victoria E. Langenheim, Robert C. Jachens
A reconnaissance for signs of a Mississippi Valley-type lead-zinc mineralizing system on the eastern flank of the Rutbah Uplift, Anbar Province, Iraq
Reconnaissance field visits and rock sampling were conducted at eight geologically selected locations within Mesozoic rocks on the eastern flank of the Rutbah Uplift, Anbar Province, western Iraq, in an attempt to determine if these rocks have been affected by a Mississippi Valley-Type (MVT) lead-zinc mineralizing system. Samples subsequently were studied by carbonate mineral staining, transmitted
Authors
Timothy S. Hayes, Mazin Mustafa, Thair Bennet
Paleogeomorphology of the early Colorado River inferred from relationships in Mohave and Cottonwood Valleys, Arizona, California and Nevada
Geologic investigations of late Miocene–early Pliocene deposits in Mohave and Cottonwood valleys provide important insights into the early evolution of the lower Colorado River system. In the latest Miocene these valleys were separate depocenters; the floor of Cottonwood Valley was ∼200 m higher than the floor of Mohave Valley. When Colorado River water arrived from the north after 5.6 Ma, a shall
Authors
Philip Pearthree, Kyle House
U-Pb zircon age data for selected sedimentary, metasedimentary, and igneous rocks from northern and central Alaska
This publication contains the complete results of U-Pb zircon age dating studies of sedimentary and metasedimentary units from northern and central Alaska that are discussed and interpreted in other reports by the author. Most of the U-Pb ages are of detrital zircons from sandstones, although U-Pb ages from igneous and sedimentary clasts from conglomerates in some of those same units are also incl
Authors
Thomas E. Moore
Stochastic modeling of a lava-flow aquifer system
This report describes preliminary three-dimensional geostatistical modeling of a lava-flow aquifer system using a multiple-point geostatistical model. The purpose of this study is to provide a proof-of-concept for this modeling approach. An example of the method is demonstrated using a subset of borehole geologic data and aquifer test data from a portion of the Calico Hills Formation, a lava-flow
Authors
Collin Cronkite-Ratcliff, Geoffrey A. Phelps
Deformation from the 1989 Loma Prieta earthquake near the southwest margin of the Santa Clara Valley, California
Damage to pavement and near-surface utility pipes, caused by the 17 October 1989, Loma Prieta earthquake, provides evidence for ground deformation in a 663 km2 area near the southwest margin of the Santa Clara Valley, California (USA). A total of 1427 damage sites, collected from more than 30 sources, are concentrated in four zones, three of which lie near previously mapped faults. In one of these
Authors
Kevin M. Schmidt, Stephen D. Ellen, David M. Peterson