A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and "rippled scour depressions"
A.B. Murray, E.R. Thieler
2004, Continental Shelf Research (24) 295-315
Recent observations of inner continental shelves in many regions show numerous collections of relatively coarse sediment, which extend kilometers in the cross-shore direction and are on the order of 100m wide. These "rippled scour depressions" have been interpreted to indicate concentrated cross-shelf currents. However, recent observations strongly suggest that they...
Development, evaluation, and application of sediment quality targets for assessing and managing contaminated sediments in Tampa Bay, Florida
D.D. MacDonald, R.S. Carr, D. Eckenrod, H. Greening, S. Grabe, C.G. Ingersoll, S. Janicki, T. Janicki, R.A. Lindskoog, E.R. Long, R. Pribble, G. Sloane, D.E. Smorong
2004, Archives of Environmental Contamination and Toxicology (46) 147-161
Tampa Bay is a large, urban estuary that is located in west central Florida. Although water quality conditions represent an important concern in this estuary, information from numerous sources indicates that sediment contamination also has the potential to adversely affect aquatic organisms, aquatic-dependent wildlife, and human health. As such, protecting...
A hydrogeologic model of stratiform copper mineralization in the Midcontinent Rift System, Northern Michigan, USA
J.B. Swenson, M. Person, Jeff P. Raffensperger, W.F. Cannon, L. G. Woodruff, M.E. Berndt
2004, Geofluids (4) 1-22
This paper presents a suite of two-dimensional mathematical models of basin-scale groundwater flow and heat transfer for the middle Proterozoic Midcontinent Rift System. The models were used to assess the hydrodynamic driving mechanisms responsible for main-stage stratiform copper mineralization of the basal Nonesuch Formation during the post-volcanic/pre-compressional phase of basin...
Erosion by flowing lava: Geochemical evidence in the Cave Basalt, Mount St. Helens, Washington
D.A. Williams, S.D. Kadel, R. Greeley, C.M. Lesher, M.A. Clynne
2004, Bulletin of Volcanology (66) 168-181
We sampled basaltic lava flows and underlying dacitic tuff deposits in or near lava tubes of the Cave Basalt, Mount St. Helens, Washington to determine whether the Cave Basalt lavas contain geochemical evidence of substrate contamination by lava erosion. The samples were analyzed using a combination of wavelength-dispersive X-ray fluorescence...
Chronology of sediment deposition in Upper Klamath Lake, Oregon
Steven M. Colman, J.P. Bradbury, J. P. McGeehin, C. W. Holmes, D. Edginton, A.M. Sarna-Wojcicki
2004, Journal of Paleolimnology (31) 139-149
A combination of tephrochronology and 14C, 210Pb, and 137Cs measurements provides a robust chronology for sedimentation in Upper Klamath Lake during the last 45 000 years. Mixing of surficial sediments and possible mobility of the radio-isotopes limit the usefulness of the 137Cs and 210Pb data, but 210Pb profiles provide reasonable...
Gas evolution in eruptive conduits: Combining insights from high temperature and pressure decompression experiments with steady-state flow modeling
M. Mangan, L. Mastin, T. Sisson
2004, Journal of Volcanology and Geothermal Research (129) 23-36
In this paper we examine the consequences of bubble nucleation mechanism on eruptive degassing of rhyolite magma. We use the results of published high temperature and pressure decompression experiments as input to a modified version of CONFLOW, the numerical model of Mastin and Ghiorso [(2000) U.S.G.S. Open-File Rep. 00-209, 53...
Earthquake scenario and probabilistic ground-shaking hazard maps for the Albuquerque-Belen-Santa Fe, New Mexico, corridor
I. Wong, S. Olig, M. Dober, W. Silva, D. Wright, P. Thomas, N. Gregor, A. Sanford, K.-W. Lin, D. Love
2004, New Mexico Geology (26) 3-33
New Mexico's population is concentrated along the corridor that extends from Belen in the south to Española in the north and includes Albuquerque and Santa Fe. The Rio Grande rift, which encompasses the corridor, is a major tectonically, volcanically, and seismically active continental rift in the western U.S. Although only...
Temporal dynamics of leafy spurge (Euphorbia esula) and two species of flea beetles (Aphthona spp.) used as biological control agents
D.L. Larson, J.B. Grace
2004, Biological Control (29) 207-214
The goal of this study was to evaluate the biological control program of leafy spurge (Euphorbia esula) in a large natural area, Theodore Roosevelt National Park, western North Dakota, USA. Aphthona lacertosa and Aphthona nigriscutis have been released at more than 1800 points in the 18,600-ha South Unit of the park beginning in 1989; most releases...
Holocene to Pliocene tectonic evolution of the region offshore of the Los Angeles urban corridor, southern California
R. G. Bohannon, J.V. Gardner, R. W. Sliter
2004, Tectonics (23)
Quaternary tectonism in the coastal belt of the Los Angeles urban corridor is diverse. In this paper we report the results of studies of multibeam bathymetry and a network of seismic reflection profiles that have been aimed at deciphering the diverse tectonism and at evaluating the relevance of published explanations...
Effects of wave shape on sheet flow sediment transport
T.-J. Hsu, D.M. Hanes
2004, Journal of Geophysical Research C: Oceans (109)
A two-phase model is implemented to study the effects of wave shape on the transport of coarse-grained sediment in the sheet flow regime. The model is based on balance equations for the average mass, momentum, and fluctuation energy for both the fluid and sediment phases. Model simulations indicate that the...
The effect of fire on mercury cycling in the soils of forested watersheds: Acadia National Park, Maine, U.S.A
A. Amirbahman, P.L. Ruck, I.J. Fernandez, T.A. Haines, J. S. Kahl
2004, Water, Air, & Soil Pollution (152) 313-331
This study compares mercury (Hg) and methylmercury (MeHg) distribution in the soils of two forested stream watersheds at Acadia National Park, Maine, U.S.A. Cadillac Brook watershed, which burned in 1947, has thin soils and predominantly deciduous vegetation. It was compared to the unburned Hadlock Brook watershed, with thicker soil and...
Changes in snowmelt runoff timing in western North America under a 'business as usual' climate change scenario
I.T. Stewart, Daniel Cayan, Michael D. Dettinger
2004, Climatic Change (62) 217-232
Spring snowmelt is the most important contribution of many rivers in western North America. If climate changes, this contribution may change. A shift in the timing of springtime snowmelt towards earlier in the year already is observed during 1948-2000 in many western rivers. Streamflow timing changes for the 1995-2099 period...
Exploring behavior of an unusual megaherbivore: A spatially explicit foraging model of the hippopotamus
R.L. Lewison, J. Carter
2004, Ecological Modelling (171) 127-138
Herbivore foraging theories have been developed for and tested on herbivores across a range of sizes. Due to logistical constraints, however, little research has focused on foraging behavior of megaherbivores. Here we present a research approach that explores megaherbivore foraging behavior, and assesses the applicability of foraging theories developed on...
Geochemical discrimination of five pleistocene lava-dam outburst-flood deposits, western Grand Canyon, Arizona
C.R. Fenton, R.J. Poreda, B.P. Nash, R. H. Webb, T.E. Cerling
2004, Journal of Geology (112) 91-110
Pleistocene basaltic lava dams and outburst‐flood deposits in the western Grand Canyon, Arizona, have been correlated by means of cosmogenic 3He (3Hec) ages and concentrations of SiO2, Na2O, K2O, and rare earth elements. These data indicate that basalt clasts and vitroclasts in a given outburst‐flood deposit came from a common source,...
Multiple-Aquifer Characterization from Single Borehole Extensometer Records
J.P. Pope, T. J. Burbey
2004, Ground Water (42) 45-58
Measurement and analysis of aquifer-system compaction have been used to characterize aquifer and confining unit properties when other techniques such as flow modeling have been ineffective at adequately quantifying storage properties or matching historical water levels in environments experiencing land subsidence. In the southeastern coastal plain of Virginia, high-sensitivity borehole...
Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed
N. Knowles, D.R. Cayan
2004, Climatic Change (62) 319-336
California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and...
Use of medium-range numerical weather prediction model output to produce forecasts of streamflow
M.P. Clark, L.E. Hay
2004, Journal of Hydrometeorology (5) 15-32
This paper examines an archive containing over 40 years of 8-day atmospheric forecasts over the contiguous United States from the NCEP reanalysis project to assess the possibilities for using medium-range numerical weather prediction model output for predictions of streamflow. This analysis shows the biases in the NCEP forecasts to be...
The Schaake shuffle: A method for reconstructing space-time variability in forecasted precipitation and temperature fields
M.R. Clark, S. Gangopadhyay, L. Hay, B. Rajagopalan, R. Wilby
2004, Journal of Hydrometeorology (5) 243-262
A number of statistical methods that are used to provide local-scale ensemble forecasts of precipitation and temperature do not contain realistic spatial covariability between neighboring stations or realistic temporal persistence for subsequent forecast lead times. To demonstrate this point, output from a global-scale numerical weather prediction model is used in...
The impact of anthropogenic land-cover change on the Florida Peninsula Sea Breezes and warm season sensible weather
C. H. Marshall, R.A. Pielke Sr., L. T. Steyaert, Debra A. Willard
2004, Monthly Weather Review (132) 28-52
During the twentieth century, the natural landscape of the Florida peninsula was transformed extensively by agriculture, urbanization, and the diversion of surface water features. The purpose of this paper is to present a numerical modeling study in which the possible impacts of this transformation on the warm season climate of...
Effects of dissolved carbonate on arsenate adsorption and surface speciation at the hematite-water interface
Y. Arai, D.L. Sparks, J.A. Davis
2004, Environmental Science & Technology (38) 817-824
Effects of dissolved carbonate on arsenate [As(V)] reactivity and surface speciation at the hematite−water interface were studied as a function of pH and two different partial pressures of carbon dioxide gas [PCO2 = 10-3.5 atm and ∼0; CO2-free argon (Ar)] using adsorption kinetics, pseudo-equilibrium adsorption/titration experiments, extended X-ray absorption...
Subsurface fate of spilled petroleum hydrocarbons in continuous permafrost
K. McCarthy, L. Walker, L. Vigoren
2004, Cold Regions Science and Technology (38) 43-54
Accidental releases of approximately 2000 m3 of fuel have resulted in subsurface contamination adjacent to Imikpuk Lake, a drinking-water source near Barrow, AK. This paper presents a conceptual model of the distribution and transport of subsurface free-phase hydrocarbons at this site. The mean annual temperature in Barrow is -13 ??C,...
Climate and hydrology of the last interglaciation (MIS 5) in Owens Basin, California: Isotopic and geochemical evidence from core OL-92
H.-C. Li, J. L. Bischoff, T.-L. Ku, Z.-Y. Zhu
2004, Quaternary Science Reviews (23) 49-63
??18O, ??13C, total organic carbon, total inorganic carbon, and acid-leachable Li, Mg and Sr concentrations on 443 samples from 32 to 83 m depth in Owens Lake core OL-92 were analyzed to study the climatic and hydrological conditions between 60 and 155 ka with a resolution of ???200 a. The...
High resolution paleoceanography of the Guaymas Basin, Gulf of California, during the past 15 000 years
J.A. Barron, D. Bukry, J. L. Bischoff
2004, Marine Micropaleontology (50) 185-207
Deep Sea Drilling Project Site 480 (27??54.10???N, 111??39.34???W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed...
Diagenetic overprinting of the sphaerosiderite palaeoclimate proxy: are records of pedogenic groundwater δ18O values preserved?
David F. Ufnar, Luis A. Gonzalez, Greg A. Ludvigson, Richard L. Brenner, Brian J. Witzkes
2004, Sedimentology (51) 127-144
Meteoric sphaerosiderite lines (MSLs), defined by invariant ??18O and variable ??13C values, are obtained from ancient wetland palaeosol sphaerosiderites (millimetre-scale FeCO3 nodules), and are a stable isotope proxy record of terrestrial meteoric isotopic compositions. The palaeoclimatic utility of sphaerosiderite has been well tested; however, diagenetically altered horizons that do not...
Elastic velocities of partially gas-saturated unconsolidated sediments
Myung W. Lee
2004, Marine and Petroleum Geology (21) 641-650
Fluid in sediments significantly affects elastic properties of sediments and gas in the pore space can be identified by a marked reduction of P-wave velocity or a decrease of Poisson's ratio. The elastic properties of gas-saturated sediments can be predicted by the classical Biot-Gassmann theory (BGT). However, parameters for the...
