Publications
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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 in the absence of an age plateau, even in cases of significant
Authors
Robert J. Fleck, Jonathan T. Hagstrum, Andrew T. Calvert, Russell C. Evarts, Richard M. Conrey
By
Energy and Minerals Mission Area, Natural Hazards Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Groundwater and Streamflow Information Program, Volcano Hazards Program, Volcano Science Center, Geology, Minerals, Energy, and Geophysics Science Center
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, weakly magnetic, and characterized by lower seismic velociti
Authors
Victoria E. Langenheim, Robert C. Jachens, Carlos Aiken
Magmatism, ash-flow tuffs, and calderas of the ignimbrite flareup in the western Nevada volcanic field, Great Basin, USA
The western Nevada volcanic field is the western third of a belt of calderas through Nevada and western Utah. Twenty-three calderas and their caldera-forming tuffs are reasonably well identified in the western Nevada volcanic field, and the presence of at least another 14 areally extensive, apparently voluminous ash-flow tuffs whose sources are unknown suggests a similar number of undiscovered cal
Authors
Christopher D. Henry, David John
Undiscovered gas resources in the Alum Shale, Denmark, 2013
Using a geology-based assessment methodology, the U.S. Geological Survey estimates a mean undiscovered volume of 6.9 trillion cubic feet of natural gas in the Alum Shale in Denmark.
Authors
Donald L. Gautier, Ronald R. Charpentier, Stephanie B. Gaswirth, Timothy R. Klett, Janet K. Pitman, Christopher J. Schenk, Marilyn E. Tennyson, Katherine J. Whidden
ASARCO Incorporated’s Car Project, 1990-94, western Gabbs Valley, Mineral Co., Nevada: precious metal exploration transitioned to geothermal exploration
No abstract available.
Authors
Peter G. Vikre, Fleetwood Koutz
Paleomagnetic contributions to the Klamath Mountains terrane puzzle-a new piece from the Ironside Mountain batholith, northern California
We obtained paleomagnetic samples from six sites within the Middle Jurassic Ironside Mountain batholith (~170 Ma), which constitutes the structurally lowest part of the Western Hayfork terrane, in the Klamath Mountains province of northern California and southern Oregon. Structural attitudes measured in the coeval Hayfork Bally Meta-andesite were used to correct paleomagnetic data from the bathol
Authors
Edward A. Mankinen, C. Sherman Grommé, W. Porter Irwin
Principal facts and an approach to collecting gravity data using near-real-time observations in the vicinity of Barstow, California
A gravity survey was done in the vicinity of Barstow, California, in which data were processed and analyzed in the field. The purpose of the data collection was to investigate possible changes in gravity across mapped Quaternary faults and to improve regional gravity coverage, adding to the existing national gravity database. Data were collected, processed, analyzed, and interpreted in the field i
Authors
G. Phelps, C. Cronkite-Ratcliff, L. Klofas
Crustal-scale recycling in caldera complexes and rift zones along the Yellowstone hotspot track: O and Hf isotopic evidence in diverse zircons from voluminous rhyolites of the Picabo volcanic field, Idaho
Rhyolites of the Picabo volcanic field (10.4–6.6 Ma) in eastern Idaho are preserved as thick ignimbrites and lavas along the margins of the Snake River Plain (SRP), and within a deep (>3 km) borehole near the central axis of the Yellowstone hotspot track. In this study we present new O and Hf isotope data and U–Pb geochronology for individual zircons, O isotope data for major phenocrysts (quartz,
Authors
Dana L. Drew, Ilya N. Bindeman, Kathryn E. Watts, Axel K. Schmitt, Bin Fu, Michael McCurry
Previously unrecognized regional structure of the Coastal Belt of the Franciscan Complex, northern California, revealed by magnetic data
Magnetic anomalies provide surprising structural detail within the previously undivided Coastal Belt, the westernmost, youngest, and least-metamorphosed part of the Franciscan Complex of northern California. Although the Coastal Belt consists almost entirely of arkosic graywacke and shale of mainly Eocene age, new detailed aeromagnetic data show that it is pervasively marked by long, narrow, and r
Authors
Victoria E. Langenheim, Robert C. Jachens, Carl M. Wentworth, Robert J. McLaughlin
Analysis of Neogene deformation between Beaver, Utah and Barstow, California: Suggestions for altering the extensional paradigm
For more than two decades, the paradigm of large-magnitude (~250 km), northwest-directed (~N70°W) Neogene extensional lengthening between the Colorado Plateau and Sierra Nevada at the approximate latitude of Las Vegas has remained largely unchallenged, as has the notion that the strain integrates with coeval strains in adjacent regions and with plate-boundary strain. The paradigm depends on poorly
Authors
R. Ernest Anderson, Sue Beard, Edward A. Mankinen, John W. Hillhouse
Normalized rare earth elements in water, sediments, and wine: identifying sources and environmental redox conditions
The concentrations of the rare earth elements (REE) in surface waters and sediments, when normalized on an element-by-element basis to one of several rock standards and plotted versus atomic number, yield curves that reveal their partitioning between different sediment fractions and the sources of those fractions, for example, between terrestrial-derived lithogenous debris and seawater-derived bio
Authors
David Z. Piper, Michael Bau
Steady rotation of the Cascade arc
Displacement of the Miocene Cascade volcanic arc (northwestern North America) from the active arc is in the same sense and at nearly the same rate as the present clockwise block motions calculated from GPS velocities in a North American reference frame. Migration of the ancestral arc over the past 16 m.y. can be explained by clockwise rotation of upper-plate blocks at 1.0°/m.y. over a linear melti
Authors
Ray E. Wells, Robert McCaffrey