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Publications

Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center

Filter Total Items: 2354

Photomosaics and logs of trenches on the San Andreas Fault at Mill Canyon near Watsonville, California

We present photomosaics and logs of the walls of trenches excavated for a paleoseismic study at Mill Canyon, one of two sites along the San Andreas fault in the Santa Cruz Mtns. on the Kelley-Thompson Ranch. This site was a part of Rancho Salsipuedes beginning in 1834. It was purchased by the present owner’s family in 1851. Remnants of a cabin/mill operations still exist up the canyon dating from
Authors
Thomas E. Fumal, Timothy E. Dawson, Rebecca Flowers, John C. Hamilton, Gordon F. Heingartner, James Kessler, Laura Samrad

Simulation of ventilation efficiency, and pre-closure temperatures in emplacement drifts at Yucca Mountain, Nevada, using Monte Carlo and composite thermal-pulse methods

Predictions of waste canister and repository driftwall temperatures as functions of space and time are important to evaluate pre-closure performance of the proposed repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. Variations in the lithostratigraphic features in densely welded and crystallized rocks of the 12.8-million-year-old Topopah Spring Tuff, espe
Authors
J.B. Case, D.C. Buesch

Eolian sediments

No abstract available.
Authors
A.J. Busacca, J. E. Beget, H. W. Markewich, D.R. Muhs, N. Lancaster, M.R. Sweeney

Numerical study of electromagnetic waves generated by a prototype dielectric logging tool

To understand the electromagnetic waves generated by a prototype dielectric logging tool, a numerical study was conducted using both the finite-difference, time-domain method and a frequency-wavenumber method. When the propagation velocity in the borehole was greater than that in the formation (e.g., an air-filled borehole in the unsaturated zone), only a guided wave propagated along the borehole.
Authors
K.J. Ellefsen, J.D. Abraham, D.L. Wright, A.T. Mazzella

Acidification of forest soil in Russia: From 1893 to present

It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30-40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils developed on ca
Authors
A.G. Lapenis, G. B. Lawrence, A.A. Andreev, A.A. Bobrov, M.S. Torn, J. W. Harden

Modeling sorption of divalent metal cations on hydrous manganese oxide using the diffuse double layer model

Manganese oxides are important scavengers of trace metals and other contaminants in the environment. The inclusion of Mn oxides in predictive models, however, has been difficult due to the lack of a comprehensive set of sorption reactions consistent with a given surface complexation model (SCM), and the discrepancies between published sorption data and predictions using the available models. The a
Authors
J.W. Tonkin, L.S. Balistrieri, J.W. Murray

A new species of Dyoros (Brachiopoda; Chonetoidea) from Nevada (United States) and stratigraphic implications for the Pennsylvanian and Permian Antler Overlap assemblage [Une nouvelle espèce de Dyoros (Brachiopoda; Chonetoidea) du Nevada (États-Unis) et i

Newly discovered fossil localities in coarse-grained deposits of the Pennsylvanian and Permian Antler overlap assemblage in the southern Shoshone Range, north-central Nevada have yielded a low-diversity assemblage consisting chiefly of a new species of chonetoidean brachiopod: Dyoros (Lissosia) nevadaensis nov. sp. The subgenus Dyoros (Lissosia), is known from Leonardian and lower Guadalupian stra
Authors
Patrick R. Racheboeuf, Thomas E. Moore, Robert B. Blodgett

Mono Lake excursion recorded in sediment of the Santa Clara Valley, California

Two intervals recording anomalous paleomagnetic inclinations were encountered in the top 40 meters of research drill hole CCOC in the Santa Clara Valley, California. The younger of these two intervals has an age of 28,090 ± 330 radiocarbon years B.P. (calibrated age ∼32.8 ka). This age is in excellent agreement with the latest estimate for the Mono Lake excursion at the type locality and confirms
Authors
Edward A. Mankinen, Carl M. Wentworth

Paleomagnetism and 40Ar/39Ar ages from volcanics extruded during the Matuyama and Brunhes Chrons near McMurdo Sound, Antarctica

Maps of virtual geomagnetic poles derived from international geomagnetic reference field models show large lobes with significant departures from the spin axis. These lobes persist in field models for the last few millenia. The anomalous lobes are associated with observation sites at extreme southerly latitudes. To determine whether these features persist for millions of years, paleomagnetic vecto
Authors
L. Tauxe, Philip B. Gans, Edward A. Mankinen

Ophiolite and volcanic arc assemblages on the Vizcaino Peninsula and Cedros Island region, Baja California Sur, Mexico: Mesozoic forearc lithosphere of the Cordilleran magmatic arc

Mesozoic ophiolites in the Vizcaíno Peninsula and Cedros Island region of Baja California Sur are suprasubduction zone Cordilleran-type ophiolites structurally juxtaposed with underlying high pressure-temperature subduction complex assemblages. The region is divided into three separate tectonostratigraphic terranes, but here we recognize stratigraphic, intrusive, and petrologie links between these
Authors
D.L. Kimbrough, Thomas E. Moore