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Year Published: 2014

Time-domain electromagnetic surveys at Fort Irwin, San Bernardino County, California, 2010–12

Between 2010 and 2012, a total of 79 time-domain electromagnetic (TEM) soundings were collected in 12 groundwater basins in the U.S. Army Fort Irwin National Training Center (NTC) study area to help improve the understanding of the hydrogeology of the NTC. The TEM data are discussed in this chapter in the context of geologic observations of the...

Buesch, David C.; Burgess, Matthew K.; Bedrosian, Paul A.
Burgess, M.K., and Bedrosian, P.A., 2014, Time-domain electromagnetic surveys at Fort Irwin, San Bernardino County, California, 2010–12, chap. F of Buesch, D.C., ed., Geology and geophysics applied to groundwater hydrology at Fort Irwin, California: U.S. Geological Survey Open-File Report 2013–1024, 64 p., https://doi.org/10.3133/ofr20131024F.

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Year Published: 2014

Airborne electromagnetic data and processing within Leach Lake Basin, Fort Irwin, California

From December 2010 to January 2011, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of Leach Lake Basin within the National Training Center, Fort Irwin, California. These data were collected to characterize the subsurface and provide information needed to understand and manage groundwater resources within Fort...

Buesch, David C.; Bedrosian, Paul A.; Ball, Lyndsay B.; Bloss, Benjamin R.
Bedrosian, P.A., Ball, L.B., and Bloss, B.R., 2014, Airborne electromagnetic data and processing within Leach Lake Basin, Fort Irwin, California, chap. G of Buesch, D.C., ed., Geology and geophysics applied to groundwater hydrology at Fort Irwin, California: U.S. Geological Survey Open File Report 2013–1024, 20 p., https://doi.org/10.3133/ofr20131024G.

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Year Published: 2014

40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA

The 40Ar/39Ar investigations of a large suite of fine-grained basaltic rocks of the Boring volcanic field (BVF), Oregon and Washington (USA), yielded two primary results. (1) Using age control from paleomagnetic polarity, stratigraphy, and available plateau ages, 40Ar/39Ar recoil model ages are defined that provide reliable age results...

Fleck, Robert J.; Hagstrum, Jonathan T.; Calvert, Andrew T.; Evarts, Russell C.; Conrey, Richard M.
Fleck, R.J., Hagstrum, J.T., Calvert, A.T., Evarts, R.C., and Conrey, R.M., 2014, 40Ar/39Ar geochronology, paleomagnetism, and evolution of the Boring volcanic field, Oregon and Washington, USA: Geosphere, v. 10, p. 1283–1314.

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Year Published: 2014

Geomorphic evidence for enhanced Pliocene-Quaternary faulting in the northwestern Basin and Range

Mountains in the U.S. Basin and Range Province are similar in form, yet they have different histories of deformation and uplift. Unfortunately, chronicling fault slip with techniques like thermochronology and geodetics can still leave sizable, yet potentially important gaps at Pliocene–Quaternary (∼105–106 yr) time scales. Here, we...

Ellis, Magdalena A; Barnes Jason B; Colgan, Joseph P.
Ellis, M.A., Barnes, J.B., and Colgan, J.P., 2015, Geomorphic evidence for enhanced Plio-Quaternary faulting in the northwestern Basin and Range: Lithosphere, v. 7(1), p. 59–72, doi:10.1130/L401.1.

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Year Published: 2014

Geophysical framework of the Peninsular Ranges batholith—Implications for tectonic evolution and neotectonics

The crustal structure of the Peninsular Ranges batholith can be divided geophysically into two parts: (1) a western mafic part that is dense, magnetic, and characterized by relatively high seismic velocities (>6.25 km/s), low heat flow (<60 mW/m2), and relatively sparse seismicity, and (2) an eastern, more felsic part that is less dense,...

Langenheim, Victoria; Jachens, Robert C.; Aiken, Carlos
Langenheim, V.E., Jachens, R.C., and Aiken, C., 2014, Geophysical framework of the Peninsular Ranges batholith—Implications for tectonic evolution and neotectonics, in Morton, D.M., and Miller, F.K., eds., Peninsular Ranges Batholith, Baja California and Southern California: Geological Society of America Memoir 211, p. 1–20, doi:10.1130/2014.1211(01).

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Year Published: 2014

Tectonic evolution of the Tualatin basin, northwest Oregon, as revealed by inversion of gravity data

The Tualatin basin, west of Portland (Oregon, USA), coincides with a 110 mGal gravity low along the Puget-Willamette lowland. New gravity measurements (n = 3000) reveal a three-dimensional (3-D) subsurface geometry suggesting early development as a fault-bounded pull-apart basin. A strong northwest-trending gravity gradient coincides with the...

McPhee, Darcy K.; Langenheim, Victoria E.; Wells, Ray; Blakely, Richard J.

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Year Published: 2014

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...

Cocker, Mark D.

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Year Published: 2014

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...

Vikre, Peter G.
in, Geological Society of Nevada Field Trip Guidebook, 2014, Special Publication 58

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Year Published: 2014

Potash: a global overview of evaporate-related potash resources, including spatial databases of deposits, occurrences, and permissive tracts: Chapter S in Global mineral resource assessment

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...

Orris, Greta J.; Cocker, Mark D.; Dunlap, Pamela; Wynn, Jeff C.; Spanski, Gregory T.; Briggs, Deborah A.; Gass, Leila; Bliss, James D.; Bolm, Karen S.; Yang, Chao; Lipin, Bruce R.; Ludington, Stephen; Miller, Robert J.; Słowakiewicz, Mirosław
Orris, G.J., Cocker, M.D., Dunlap, P., Wynn, J.C., Spanski, G.T., Briggs, D.G., and Gass, L., with contributions from Bliss, J.D., Bolm, K.S., Yang, C., Lipin, B.R., Ludington, S., Miller, R.J., and Slowakiewicz, M., 2014, Potash—A global overview of evaporite-related potash resources, including spatial databases of deposits, occurrences, and permissive tracts: U.S. Geological Survey Scientific Investigations Report 2010–5090–S, XX p., and spatial data, http://dx.doi.org/10.3133/sir20105090s.

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Year Published: 2014

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-...

Buesch, David C.; Jachens, Robert C.; Langenheim, V.E.
Jachens, R.C., and Langenheim, V.E., 2014, Gravity survey and interpretation of Fort Irwin and vicinity, Mojave Desert, California, chap. H of Buesch, D.C., ed., Geology and geophysics applied to groundwater hydrology at Fort Irwin, California: U.S. Geological Survey Open-File Report 2013–1024, 11 p., https://doi.org/10.3133/ofr20131024H.

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Year Published: 2014

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...

Buesch, David C.; Miller, David M.; Menges, Christopher M.; Lidke, David J.
Miller, D.M., Menges, C.M., and Lidke, D.J., 2014, Generalized surficial geologic map of the Fort Irwin area, San Bernardino County, California, chap. B of Buesch, D.C., ed., Geology and geophysics applied to groundwater hydrology at Fort Irwin, California: U.S. Geological Survey Open-File Report 2013–1024, 11 p., scale 1:100,000, https://doi.org/10.3133/ofr20131024B.

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Year Published: 2014

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...

Buesch, David C.; Buesch, David C.
Buesch, D.C., 2014, Introduction to the geologic and geophysical studies of Fort Irwin, California, chap. A of Buesch, D.C., ed., Geology and geophysics applied to groundwater hydrology at Fort Irwin, California: U.S. Geological Survey Open-File Report 2013–1024, 8 p., https://doi.org/10.3133/ofr20131024A.