Jurassic "savannah" - Plant taphonomy and climate of the Morrison Formation (Upper Jurassic, Western USA)
Judith T. Parrish, F. Peterson, C.E. Turner
2004, Sedimentary Geology (167) 137-162
The Morrison Formation contains six plant taphofacies: Wood, whole-leaf, leaf-mat, root, common carbonaceous debris, and rare carbonaceous debris. None of these taphofacies is common in the Morrison; particularly striking is the paucity of wood, even in more reducing environments. The flora of the Morrison Formation is distinct in the Kimmeridgian...
Uranium-series coral ages from the US Atlantic Coastal Plain-the "80 ka problem" revisited
J.F. Wehmiller, K. R. Simmons, H. Cheng, R. Lawrence Edwards, J. Martin-McNaughton, L.L. York, D.E. Krantz, C.-C. Shen
2004, Quaternary International (120) 3-14
Uranium series coral ages for emergent units from the passive continental margin US Atlantic Coastal Plain (ACP) suggest sea level above present levels at the end of marine oxygen isotope stage (MIS) 5, contradicting age-elevation relations based on marine isotopic or coral reef models of ice equivalent sea level. We...
Real-time seismic monitoring needs of a building owner - And the solution: A cooperative effort
M. Çelebi, A. Sanli, M. Sinclair, S. Gallant, D. Radulescu
2004, Earthquake Spectra (20) 333-346
A recently implemented advanced seismic monitoring system for a 24-story building facilitates recording of accelerations and computing displacements and drift ratios in near-real time to measure the earthquake performance of the building. The drift ratio is related to the damage condition of the specific building. This system meets the owner's...
Phenotypic variation and vulnerability to predation in juvenile bluegill sunfish (Lepomis macrochirus)
S. R. Chipps, J.A. Dunbar, David H. Wahl
2004, Oecologia (138) 32-38
Bluegill sunfish (Lepomis macrochirus) are known to diversify into two forms specialized for foraging on either limnetic or littoral prey. Because juvenile bluegills seek vegetative cover in the presence of largemouth bass (Micropterus salmoides) predators, natural selection should favor the littoral body design at size ranges most vulnerable to predation....
Use of chemical and isotopic tracers to assess nitrate contamination and ground-water age, Woodville Karst Plain, USA
B. G. Katz, A.R. Chelette, T.R. Pratt
2004, Journal of Hydrology (289) 36-61
Concerns regarding ground-water contamination in the Woodville Karst Plain have arisen due to a steady increase in nitrate-N concentrations (0.25-0.90 mg/l) during the past 30 years in Wakulla Springs, a large regional discharge point for water (9.6 m3/s) from the Upper Floridan aquifer (UFA). Multiple isotopic and chemical tracers were...
The effect of elevated methane pressure on methane hydrate dissociation
S. Circone, L.A. Stern, S. H. Kirby
2004, American Mineralogist (89) 1192-1201
Methane hydrate, equilibrated at P, T conditions within the hydrate stability field, was rapidly depressurized to 1.0 or 2.0 MPa and maintained at isobaric conditions outside its stability field, while the extent and rate of hydrate dissociation was measured at fixed, externally maintained temperatures between 250 and 288 K. The...
Winter habitat use by cutthroat trout in the Snake River near Jackson, Wyoming
D.D. Harper, A.M. Farag
2004, Transactions of the American Fisheries Society (133) 15-25
Winter habitat use by Yellowstone cutthroat trout Oncorhynchus clarki bouvieri was monitored with radiotelemetry during November-March 1998-2001 in channelized and unaltered sections of the Snake River near Jackson, Wyoming. The use of run and off-channel pool habitat was significantly correlated to water temperature; run use was most frequent when mean...
Estimating stage-specific daily survival probabilities of nests when nest age is unknown
T.R. Stanley
2004, The Auk (121) 134-147
Estimation of daily survival probabilities of nests is common in studies of avian populations. Since the introduction of Mayfield's (1961, 1975) estimator, numerous models have been developed to relax Mayfield's assumptions and account for biologically important sources of variation. <a...
Nitrate and herbicide loading in two groundwater basins of Illinois' sinkhole plain
S.V. Panno, W.R. Kelly
2004, Journal of Hydrology (290) 229-242
This investigation was designed to estimate the mass loading of nitrate (NO3-) and herbicides in spring water discharging from groundwater basins in an agriculturally dominated, mantled karst terrain. The loading was normalized to land use and NO3- and herbicide losses were compared to estimated losses in other agricultural areas of...
Quantification of nearshore morphology based on video imaging
P. S. Alexander, R.A. Holman
2004, Marine Geology (208) 101-111
The Argus network is a series of video cameras with aerial views of beaches around the world. Intensity contrasts in time exposure images reveal areas of preferential breaking, which are closely tied to underlying bed morphology. This relationship was further investigated, including the effect of tidal elevation and wave height...
Effects of elk herbivory on vegetation and nitrogen processes
Kathryn A. Schoenecker, Francis J. Singer, Linda Zeigenfuss, Dan Binkley, Romulo S.C. Menezes
2004, Journal of Wildlife Management (68) 837-849
We used 35-year and 4-year ungulate exclosures to determine the effects of elk (Cervus elaphus) herbivory on above-ground and below-ground production and soil fertility on the elk winter range in Rocky Mountain National Park (RMNP), Colorado, USA. We used paired grazed and ungrazed plots to evaluate ungulate herbivory effects in...
Recalculated probability of M ≥ 7 earthquakes beneath the Sea of Marmara, Turkey
T. Parsons
2004, Journal of Geophysical Research B: Solid Earth (109)
New earthquake probability calculations are made for the Sea of Marmara region and the city of Istanbul, providing a revised forecast and an evaluation of time-dependent interaction techniques. Calculations incorporate newly obtained bathymetric images of the North Anatolian fault beneath the Sea of Marmara [Le Pichon et al., 2001; Armijo...
Attempting to bridge the gap between laboratory and seismic estimates of fracture energy
Art McGarr, Joe B. Fletcher, N.M. Beeler
2004, Geophysical Research Letters (31)
To investigate the behavior of the fracture energy associated with expanding the rupture zone of an earthquake, we have used the results of a large-scale, biaxial stick-slip friction experiment to set the parameters of an equivalent dynamic rupture model. This model is determined by matching the fault slip, the static...
Biochemical, histological and behavioural aspects of visual function during early development of rainbow trout
Paulo S. M. Carvalho, Douglas B. Noltie, D. E. Tillitt
2004, Journal of Fish Biology (64) 833-850
Retinal structure and concentration of retinoids involved in phototransduction changed during early development of rainbow trout Oncorhynchus mykiss, correlating with improvements in visual function. A test chamber was used to evaluate the presence of optokinetic or optomotor responses and to assess the functionality of the integrated cellular, physiological and biochemical...
Evaluation of longitudinal dispersivity estimates from simulated forced‐ and natural‐gradient tracer tests in heterogeneous aquifers
Claire R. Tiedeman, Paul A. Hsieh
2004, Water Resources Research (40)
We simulate three types of forced‐gradient tracer tests (converging radial flow, unequal strength two well, and equal strength two well) and natural‐gradient tracer tests in multiple realizations of heterogeneous two‐dimensional aquifers with a hydraulic conductivity distribution characterized by a spherical variogram. We determine longitudinal dispersivities (αL) by analysis of forced‐gradient...
Structural model of the San Bernardino basin, California, from analysis of gravity, aeromagnetic, and seismicity data
M. Anderson, J. Matti, R. Jachens
2004, Journal of Geophysical Research B: Solid Earth (109)
The San Bernardino basin is an area of Quaternary extension between the San Jacinto and San Andreas Fault zones in southern California. New gravity data are combined with aeromagnetic data to produce two- and three-dimensional models of the basin floor. These models are used to identify specific faults that have...
Deformation of quaternary strata and its relationship to crustal folds and faults, south-central Puget Lowland, Washington State
D. B. Booth, K. G. Troost, J.T. Hagstrum
2004, Geology (32) 505-508
Folded Quaternary deposits across the south-central Puget Lowland, an area just south of the Seattle fault that extends across the Seattle uplift and its boundary with the adjacent Tacoma basin, provide increased resolution of the character and rate of crustal deformation. They also constrain alternative, and partly incompatible, views of...
Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: A critical appraisal of across-arc compositional variation
W. Hildreth, J. Fierstein, D. F. Siems, J. R. Budahn, J. Ruiz
2004, Contributions to Mineralogy and Petrology (147) 243-275
Physical and compositional data and K-Ar ages are reported for 14 rear-arc volcanoes that lic 11-22 km behind the narrowly linear volcanic front defined by the Mount Katmai-to-Devils Desk chain on the Alaska Peninsula. One is a 30-km3 stratocone (Mount Griggs; 51-63% SiO2) active intermittently from 292 ka to Holocene....
Exceptionally fast growth rate of <100-yr-old tufa, Big Soda Lake, Nevada: Implications for using tufa as a peleoclimate proxy
Michael R. Rosen, G.B. Arehart, M.S. Lico
2004, Geology (32) 409-412
Large tufa mounds (>3 m tall, with a basal circumference of 5 m) have been discovered on the margin of Big Soda Lake, Nevada, USA. These tufa mounds are rooted at a maximum of 4 m below the current lake surface and are actively forming from groundwater seepage, which can...
Comparison of MODIS and AVHRR 16-day normalized difference vegetation index composite data
Kevin P. Gallo, Lei Ji, Bradley C. Reed, John L. Dwyer, Jeffery C. Eidenshink
2004, Geophysical Research Letters (31)
Normalized difference vegetation index (NDVI) data derived from visible and near-infrared data acquired by the MODIS and AVHRR sensors were compared over the same time periods and a variety of land cover classes within the conterminous USA. The relationship between the AVHRR derived NDVI values and those of future sensors...
Ecological correlates of fish movement in a network of Virginia streams
B. Albanese, P. L. Angermeier, S. Dorai-Raj
2004, Canadian Journal of Fisheries and Aquatic Sciences (61) 857-869
Identifying factors that influence fish movement is a key step in predicting how populations respond to environmental change. Using mark-recapture (four species) and trap capture (eight species) data, we examined relationships between three attributes of movement and 15 ecological variables. The probability of emigrating from a reach was positively related...
Hydrogeologic controls on the transport and fate of nitrate in ground water beneath riparian buffer zones: Results from thirteen studies across the United States
L.J. Puckett
2004, Water Science and Technology (49) 47-53
During the last two decades there has been growing interest in the capacity of riparian buffer zones to remove nitrate from ground waters moving through them. Riparian zone sediments often contain organic carbon, which favors formation of reducing conditions that can lead to removal of nitrate through denitrification. Over the...
Non-double-couple microearthquakes at Long Valley caldera, California, provide evidence for hydraulic fracturing
G.R. Foulger, B.R. Julian, D.P. Hill, A.D. Pitt, P.E. Malin, E. Shalev
2004, Journal of Volcanology and Geothermal Research (132) 45-71
Most of 26 small (0.4≲M≲3.1) microearthquakes at Long Valley caldera in mid-1997, analyzed using data from a dense temporary network of 69 digital three-component seismometers, have significantly non-double-couple focal mechanisms, inconsistent with simple shear faulting. We determined their mechanisms by inverting P- and S-wave polarities and amplitude ratios using linear-programming methods, and...
Interpretation of concentration‐discharge patterns in acid‐neutralizing capacity during storm flow in three small, forested catchments in Shenandoah National Park, Virginia
Karen C. Rice, Jeffrey G. Chanat, George M. Hornberger, James R. Webb
2004, Water Resources Research (40)
Episodic concentration‐discharge (c‐Q) plots are a popular tool for interpreting the hydrochemical response of small, forested catchments. Application of the method involves assuming an underlying conceptual model of runoff processes and comparing observed c‐Q looping patterns with those predicted by the model. We analyzed and interpreted c‐Q plots of acid‐neutralizing capacity (ANC) for 133...
Community structure of fishes inhabiting aquatic refuges in a threatened Karst wetland and its implications for ecosystem management
Robert M. Kobza, J.C. Trexler, W.F. Loftus, S.A. Perry
2004, Biological Conservation (116) 153-165
We illustrate the importance of subsurface refuges for conservation of aquatic fauna with our studies of karstic wetlands in Everglades National Park, Florida, USA. Managers have proposed that water levels there should not fall more than 46 cm below ground level for more than 90 days annually. In four areas,...
