Two lithospheric profiles across southern California derived from gravity and seismic data
T. Romanyuk, Walter D. Mooney, Shane T. Detweiler
2007, Journal of Geodynamics (43) 274-307
We present two detailed 2-D density transects for the crust and uppermost mantle across southern California using a linear gravity inversion technique. This technique parameterizes the crust and upper mantle as a set of blocks that are based on published geologic and seismic...
Why the sacramento delta area differs from other parts of the great valley: numerical modeling of thermal structure and thermal subsidence of forearc basins
V.O. Mikhailov, T. Parsons, R.W. Simpson, E.P. Timoshkina, C. Williams
2007, Izvestiya, Physics of the Solid Earth (43) 75-90
Data on present-day heat flow, subsidence history, and paleotemperature for the Sacramento Delta region, California, have been employed to constrain a numerical model of tectonic subsidence and thermal evolution of forearc basins. The model assumes an oceanic basement with an initial thermal profile dependent on its age subjected to refrigeration...
Prioritizing bottomland hardwood forest sites for protection and augmentation
J. Carter, J. Biagas
2007, Natural Areas Journal (27) 72-82
Bottomland hardwood forest has been greatly diminished by conversion to agriculture. Less than 25% of the pre-Columbian bottomland hardwood forests remain in the southeastern United States. Because of the valuable ecological and hydrological functions performed by these forests, their conservation and restoration has been a high priority. Part of these...
Survey trends of North American shorebirds: Population declines or shifting distributions?
Jonathan Bart, Stephen Brown, Brian A. Harrington, R.I. Guy Morrison
2007, Journal of Avian Biology (38) 73-82
We analyzed data from two surveys of fall migrating shorebirds in central and eastern North America to estimate annual trends in means per survey and to determine whether trends indicate a change in population size or might have been caused by other factors. The analysis showed a broad decline in...
Upper cretaceous microbial petroleum systems in north-central Montana
Paul G. Lillis
2007, Mountain Geologist (44) 11-35
Cenomanian to Campanian rocks of north-central Montana contain shallow economic accumulations of dry natural gas derived from microbial methanogenesis. The methanogens utilized carbon dioxide derived from organic matter in the marginal marine sediments and hydrogen from in situ pore water to generate methane. The most recent USGS assessment of the shallow...
Pre-eruption recharge of the Bishop magma system
D.A. Wark, W. Hildreth, F.S. Spear, D.J. Cherniak, E.B. Watson
2007, Geology (35) 235-238
The 650 km3 rhyolitic Bishop Tuff (eastern California, USA), which is stratigraphically zoned with respect to temperatures of mineral equilibration, reflects a corresponding thermal gradient in the source magma chamber. Consistent with previous work, application of the new TitaniQ (Ti-in-quartz) thermometer to quartz phenocryst rims documents an ∼100 °C temperature increase...
Effects of season, rainfall, and hydrogeomorphic setting on mangrove tree growth in Micronesia
K. W. Krauss, B. D. Keeland, J. A. Allen, K. C. Ewel, Daniel J. Johnson
2007, Biotropica (39) 161-170
Seasonal patterns of tree growth are often related to rainfall, temperature, and relative moisture regimes. We asked whether diameter growth of mangrove trees in Micronesia, where seasonal changes are minimal, is continuous throughout a year or conforms to an annual cycle. We installed dendrometer bands on Sonneratia alba and Bruguiera...
Factors influencing ground-water recharge in the eastern United States
B. T. Nolan, R. W. Healy, P.E. Taber, K. Perkins, K.J. Hitt, D.M. Wolock
2007, Journal of Hydrology (332) 187-205
Ground-water recharge estimates for selected locations in the eastern half of the United States were obtained by Darcian and chloride-tracer methods and compared using statistical analyses. Recharge estimates derived from unsaturated-zone (RUZC) and saturated-zone (RSZC) chloride mass balance methods are less variable (interquartile ranges or IQRs are 9.5 and 16.1...
Littoral fish assemblages of the alien-dominated Sacramento-San Joaquin Delta, California, 1980-1983 and 2001-2003
L. R. Brown, D. Michniuk
2007, Estuaries and Coasts (30) 186-200
We analyzed monthly boat electrofishing data to characterize the littoral fish assemblages of five regions of the Sacramento-San Joaquin Delta (northern, southern, eastern, western, and central), California, during two sampling periods, 1980-1983 (1980s) and 2001-2003 (2000s), to provide information pertinent to the restoration of fish populations in this highly altered...
Resource availability, matrix quality, microclimate, and spatial pattern as predictors of patch use by the Karner blue butterfly
R. Grundel, N.B. Pavlovic
2007, Biological Conservation (135) 135-144
Determination of which aspects of habitat quality and habitat spatial arrangement best account for variation in a species’ distribution can guide management for organisms such as the Karner blue butterfly (Lycaeides melissa samuelis), a federally endangered subspecies inhabiting savannas of Midwest and Eastern United States. We examined the extent to...
Solar forcing of Gulf of California climate during the past 2000 yr suggested by diatoms and silicoflagellates
John A. Barron, David Bukry
2007, Marine Micropaleontology (62) 115-139
High-resolution records of the past 2000 yr are compared in a north–south transect (28° N to 24° N) of three cores from the eastern slopes of the Guaymas, Carmen, and Pescadero Basins of the Gulf of California (hereafter referred to as the “Gulf”). Evenly-spaced samples from the varved sediments in each...
Silurian extension in the Upper Connecticut Valley, United States and the origin of middle Paleozoic basins in the Québec embayment
D.W. Rankin, R.A. Coish, R. D. Tucker, Z.X. Peng, S. A. Wilson, A.A. Rouff
2007, American Journal of Science (307) 216-264
Pre-Silurian strata of the Bronson Hill arch (BHA) in the Upper Connecticut Valley, NH-VT are host to the latest Ludlow Comerford Intrusive Suite consisting, east to west, of a mafic dike swarm with sheeted dikes, and an intrusive complex. The rocks are mostly mafic but with compositions ranging from gabbro...
Cycles of hurricane landfalls on the eastern United States linked to changes in Atlantic sea-surface temperatures
Richard Z. Poore, Terry Quinn, Julie Richey, Jackie L. Smith
2007, Circular 1306-2A
The occurrence of hurricane landfalls on the United States may be related to alternating intervals of persistent above-average and below-average surface temperature of the North Atlantic Ocean. The cycle of temperature variations, known as the Atlantic Multidecadal Oscillation (AMO), has been identified by study of records based on thermometer readings...
Impacts of Hurricane Rita on the beaches of western Louisiana
Hilary F. Stockdon, Laura A. Fauver, Sallenger Jr., C. Wayne Wright
2007, Circular 1306-5D
Hurricane Rita made landfall as a category 3 storm in western Louisiana in late September 2005, 1 month following Hurricane Katrina's devastating landfall in the eastern part of the State. Large waves and storm surge inundated the lowelevation coastline, destroying many communities and causing extensive coastal change including beach, dune,...
Origin and emplacement of impactites in the Chesapeake Bay impact structure, Virginia, USA
J. Wright Horton, Jr., Gregory Gohn, David S. Powars, Lucy E. Edwards
2007, Special Paper of the Geological Society of America 73-97
The late Eocene Chesapeake Bay impact structure, located on the Atlantic margin of Virginia, may be Earth's best-preserved large impact structure formed in a shallow marine, siliciclastic, continental-shelf environment. It has the form of an inverted...
Restoring resilience to the Gulf of Mexico coast
Gregory J. Smith
2007, Circular 1306-1A
Hurricane Katrina and its destructive aftermath in 2005 were unprecedented. Hurricanes Dennis, Rita, and Wilma were also powerful hurricanes affecting the Gulf of Mexico that year. These storms highlighted the need to integrate science that supports restoration of natural landscapes with intelligent coastal planning. The following essay describes both the...
Geology of the Yucca Mountain site area, southwestern Nevada
W. R. Keefer, J.W. Whitney, D.C. Buesch
2007, Memoir of the Geological Society of America (199) 53-103
Yucca Mountain in southwestern Nevada is a prominent, irregularly shaped upland formed by a thick apron of Miocene pyroclastic-flow and fallout tephra deposits, with minor lava flows, that was segmented by through-going, large-displacement normal faults into a series of north-trending, eastwardly tilted structural blocks. The principal volcanic-rock units are the...
Pattern and potential causes of White-faced Ibis, Plegadis chihi, establishment in the northern prairie and parkland region of North America
Jill A. Shaffer, Gregory A. Knutsen, Ron E. Martin, Joel S. Brice
2007, Canadian Field-Naturalist (121) 46-56
The Northern Prairie and Parkland Waterbird Conservation Plan calls for renewed attention to determining the current status of waterbird populations, their distributions, and conservation needs. It highlights the need for baseline information on the White-faced Ibis (Plegadis chihi). In response, we examined the historical and current distribution of the ibis...
Chesapeake Inundation Prediction System (CIPS): A regional prototype for a national problem
B. Stamey, W. Smith, K. Carey, D. Garbin, F. Klein, Hongfang Wang, J. Shen, W. Gong, J. Cho, D. Forrest, C. Friedrichs, W. Boicourt, M. Li, M. Koterba, D. King, J. Titlow, E. Smith, A. Siebers, J. Billet, J. Lee, Douglas R. Manning, G. Szatkowski, D. Wilson, P. Ahnert, J. Ostrowski
2007, Conference Paper, Oceans Conference Record (IEEE)
Recent Hurricanes Katrina and Isabel, among others, not only demonstrated their immense destructive power, but also revealed the obvious, crucial need for improved storm surge forecasting and information delivery to save lives and property in future storms. Current operational methods and the storm surge and inundation products do not adequately...
ASAR images a diverse set of deformation patterns at Kilauea volcano, Hawai'i
Michael P. Poland
2007, Conference Paper
Since 2003, 27 independent look angles have been acquired by ENVISAT’s Advanced Synthetic Aperture Radar (ASAR) instrument over the island of Hawai`i, allowing for the formation of thousands of interferograms showing deformation of the ground surface. On Kīlauea volcano, a transition from minor to broad-scale summit inflation was observed by...
Detrital mineral chronology of the Uinta Mountain Group: Implications for the Grenville flood in southwestern Laurentia
P.A. Mueller, D.A. Foster, D.W. Mogk, J. L. Wooden, George D. Kamenov, J.J. Vogl
2007, Geology (35) 431-434
Numerous studies have shown that large quantities of Grenville-age detritus dominate Neoproterozoic to Cambrian arenites in southwest Laurentia (southwestern United States). U-Pb ages and Hf isotopic compositions of zircons and 40Ar/39Ar ages of white mica from clastic sedimentary rocks of the Neoproterozoic Uinta Mountain...
Crustal controls on magmatic-hydrothermal systems: A geophysical comparison of White River, Washington, with Goldfield, Nevada
R.J. Blakely, D. A. John, S. E. Box, B. R. Berger, R.J. Fleck, R. P. Ashley, G.R. Newport, G.R. Heinemeyer
2007, Geosphere (3) 91-107
The White River altered area, Washington, and the Goldfield mining district, Nevada, are nearly contemporaneous Tertiary (ca. 20 Ma) calc-alkaline igneous centers with large exposures of shallow (<1 km depth) magmatic-hydrothermal, acid-sulfate alteration. Goldfield is the largest known high-sulfidation gold deposit in North...
Modern foraminiferal facies in a subtropical estuarine channel, Bertioga, São Paulo, Brazil
P.P.B. Eichler, B.B. Eichler, L. B. De Miranda, A.R. Rodrigues
2007, Journal of Foraminiferal Research (37) 234-247
Numerical analyses of modern foraminiferal abundance and environmental data from the Bertioga Channel (Sa??o Paulo, Brazil) reveal multiple biofacies within an overall paralic setting. Despite its fisheries, mariculture and attraction to tourists, the environmental state of Bertioga Channel remains poorly studied. The present investigation is an attempt to partly fill...
"Did you feel it?" Intensity data: A surprisingly good measure of earthquake ground motion
G. M. Atkinson, D.J. Wald
2007, Seismological Research Letters (78) 362-368
The U.S. Geological Survey is tapping a vast new source of engineering seismology data through its "Did You Feel It?" (DYFI) program, which collects online citizen responses to earthquakes. To date, more than 750,000 responses have been compiled in the United States alone. The DYFI data make up in quantity...
Assessment of contamination from arsenical pesticide use on orchards in the great valley region, Virginia and West Virginia, USA
Gilpin R. Robinson Jr., Peter Larkins, Carol J. Boughton, Bradley W. Reed, Philip L. Sibrell
2007, Journal of Environmental Quality (36) 654-663
Lead arsenate pesticides were widely used in apple orchards from 1925 to 1955. Soils from historic orchards in four counties in Virginia and West Virginia contained elevated concentrations of As and Pb, consistent with an arsenical pesticide source. Arsenic concentrations in approximately 50% of the orchard site soils and approximately...
