Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

2004

Discipline
Institution
Keyword
Publication
Publication Type

Articles 331 - 360 of 432

Full-Text Articles in Earth Sciences

Modeling The Hydrogeochemistry Of Denitrification In The Elk Valley Aquifer, Paul A. Skubinna Jan 2004

Modeling The Hydrogeochemistry Of Denitrification In The Elk Valley Aquifer, Paul A. Skubinna

Theses and Dissertations

Nitrate (NO₃¯) in groundwater has become an important tissue in the last few decades. It is known to cause methemoglobinemia, commonly known as “blue baby syndrome,” and is suspected of being a carcinogen. The most common sources for dissolved NO₃¯ in shallow groundwater include excessive application of nitrogenous fertilizers, misuse of septic systems, improper disposal of domestic wastewater or sludge, and livestock waste.

Denitrification is the most effective sink for NO₃¯. The Elk Valley aquifer (EVA) of eastern North Dakota is known to support denitrification. The objective of this study was to gain a better understanding of the geochemical processes …


Discontinuities In The Icebox Formation (Ordovician), Williston Basin, North Dakota And Montana, Aaron J. Ulishney Jan 2004

Discontinuities In The Icebox Formation (Ordovician), Williston Basin, North Dakota And Montana, Aaron J. Ulishney

Theses and Dissertations

The Ordovician Winnipeg Group is composed of three formations; in ascending order, the Black Island Formation, the Icebox Formation, and the Roughlock Formation. The Icebox Formation is largely composed of shale. This work shows that discontinuities and coarser facies exist within the Icebox Formation and that they are traceable throughout the subsurface of North Dakota and eastern Montana. This work also illustrates possible sea-level changes during the deposition of the Icebox Formation along with probable source areas providing detrital sediments into the study area.

Gamma-ray wireline logs were used to distinguish the formations of the Winnipeg Group from each other, …


A Boundary Element Method For Thermo-Poroelasticity With Applications In Rock Mechanics, Qiang Zhang Jan 2004

A Boundary Element Method For Thermo-Poroelasticity With Applications In Rock Mechanics, Qiang Zhang

Theses and Dissertations

Coupled thermal and poromechanical processes play an important role in many geomechanics problems, such as borehole stability analysis and studies of initiation and propagation of hydraulic fractures. Thermal effects, as well as hydraulic effects, can greatly change the stresses and pore pressure fields around an underground opening. This is due to the fact that thermal loading induces a volumetric deformation because of thermal expansion/contraction of both the pore fluid and the rock solid. Volumetric expansion can result in significant pressurization of the pore fluid. In order to take into account the influence of temperature gradients on pore pressure and stresses, …


Epibiont Guilds As Paleoecological Tools In Environmental Analysis: An Example From Modern And Ordovician Shell Substrates, Stacy M. Boore Jan 2004

Epibiont Guilds As Paleoecological Tools In Environmental Analysis: An Example From Modern And Ordovician Shell Substrates, Stacy M. Boore

Honors Papers

Paleocommunities of encrusting organisms exhibit characteristics that allow comparisons of modern and fossil systems and subsequent environmental analyses. Encrusting organisms attach to a substrate that is generally limited in area. Interactions between bionts and the host organism, and bionts and the environment, are preserved on epibiont encrusted fossils. Modern biont communities from known environments can be compared to fossil biont communities in order to determine the ancient environment experienced by that fossil. Using epibionts as a tool in paleo-environmental analyses employs the somewhat problematic idea that the present can be used as a key to the past. I suggest that …


Microstructures And Deformation In Some Fault Rocks From The Mcconnell Thrust At Mount Yamnuska (Alberta): Implications For Fluid Flow And Faulting And Cycles Of Strain-Hardening And Softening, Lowell Miyagi Jan 2004

Microstructures And Deformation In Some Fault Rocks From The Mcconnell Thrust At Mount Yamnuska (Alberta): Implications For Fluid Flow And Faulting And Cycles Of Strain-Hardening And Softening, Lowell Miyagi

Honors Papers

Fault rocks from the McConnell thrust consist of limestone mylonite, carbonate and shale cataclasites, and deformed sandstones. The limestone mylonite in the hanging wall mayor may not show different levels of cataclastic overprint. Just below these hanging wall rocks is a zone of comminuted material. This zone contains cataclasites that are produced by the mixing of hanging wall and footwall materials. Underneath this unit are the shale cataclasites of the footwall and beneath this are deformed sandstones that become progressively less deformed further from the fault zone. Based on microstructural evidence these rocks show cycles of mesoscopically brittle and ductile …


Impact Of Black Shale Weathering On Sediment Quality, G. M. Ogendi, R. E. Hannigan, Jerry L. Farris, D. Smith Jan 2004

Impact Of Black Shale Weathering On Sediment Quality, G. M. Ogendi, R. E. Hannigan, Jerry L. Farris, D. Smith

Journal of the Arkansas Academy of Science

Weathering of black shales leads to elevated metal concentrations in both surface water and stream sediments. In spite of the recent focus on black shales, few data exist on the ecological impacts of this process particularly on aquatic organisms. The key objective of this study was to determine the impact of trace metal concentrations in sediments upon aquatic organisms. To achieve the above objective, stream sediment samples were collected from streams draining black shale and limestone (used as a reference stream) lithologies located in central Arkansas between June 2003 and January 2004. Trace metal concentrations were measured by the dynamic …


A Large Late Pleistocene Outburst Flood From Pluvial Lakes Alvord And Coyote Into The Owyhee River, Oregon, Deron Torrey Carter Jan 2004

A Large Late Pleistocene Outburst Flood From Pluvial Lakes Alvord And Coyote Into The Owyhee River, Oregon, Deron Torrey Carter

All Master's Theses

A large late-Pleistocene flood traveled into the Owyhee River as a result of a rise and subsequent outburst from pluvial Lake Alvord in southeastern Oregon. Lake Alvord breached Big Sand Gap after reaching an elevation of 1292 m, releasing 11.3 km3 into the adjacent Coyote Basin before stabilizing at an elevation of about 1280 m. Overflow then spilled out of the Coyote Basin through two outlets at 1278 m and into the Crooked Creek drainage of the Owyhee River. The flood created a series of deeply incised canyons, scabland topography and deposited numerous boulder bars containing imbricated clasts up to …


Estimation Of Primary Production And Carbon Flux In Antarctic Coastal Waters: A Modeling Study, Hae-Cheol Kim Jan 2004

Estimation Of Primary Production And Carbon Flux In Antarctic Coastal Waters: A Modeling Study, Hae-Cheol Kim

OES Theses and Dissertations

This study presents results from models that are designed to simulate the underwater light field, to simulate phytoplankton primary production, and to estimate the fate of phytoplankton carbon in continental shelf waters of the west Antarctic Peninsula (WAP) and Ross Sea. Simulation of the underwater light field required derivation of new coefficient sets for power function-type cloud cover correction algorithms, which were found to be influenced by multiple reflections between the bottom of clouds and the surface. The coefficient sets indicate that the spectral effect of clouds on the properties of the surface irradiance was spectrally-neutral for wavelengths greater than …


Groundwater Trends In The Kent-Frankland Sub-Region, Arjen Ryder Jan 2004

Groundwater Trends In The Kent-Frankland Sub-Region, Arjen Ryder

Natural resources published reports

The South Coast Regional Initiative Planning Team (SCRIPT) has divided the South Coast region of Western Australia into six sub-regions. Kent-Frankland covers the catchments of the Frankland, Gordon and Kent' Rivers. Approximately two-thirds (450,000 ha) has been cleared for agriculture. This publication describes the groundwater trends, risk of shallow watertables, and technical feasibility of salinity management on agricultural land.

Soil-landscape zones are spatial units based on geology and geomorphology. Since most groundwater processes in WA are controlled by the geologic and regolith properties, these zones can be used for allocating hydrological attributes, such as groundwater characteristics and trends. The hydrological …


Groundwater Trends In The Albany Hinterland Sub-Region, Arjen Ryder Jan 2004

Groundwater Trends In The Albany Hinterland Sub-Region, Arjen Ryder

Natural resources published reports

The South Coast Regional Initiative Planning Team (SCRIPT) has divided the South Coast region of Western Australia into six sub-regions The Albany Hinterland is in the western portion (see Figure 1). It is bounded by the Pallinup River in the east. Stirling Ranges to the north and the Kent River catchment boundary in the west. Two-thirds (580.000 ha) of the sub-region has been cleared for agriculture This publication describes the groundwater trends, risk of shallow watertables, and technical feasibility of salinity management within the agricultural land

Soil-landscape zones are spatial units based on geology and geomorphology. Since most groundwater processes …


Glacial Deposits, Vol. 32, 2003-2004, Department Of Geography-Geology Jan 2004

Glacial Deposits, Vol. 32, 2003-2004, Department Of Geography-Geology

Glacial Deposits

Newsletter of the Department of Geography-Geology


Seismic Stratigraphic Investigation Of The Ukpokiti Field Channel Complex, Oml 108, Offshore Nigeria, Northwestern Niger Delta, Toby Latwan Stewart Jan 2004

Seismic Stratigraphic Investigation Of The Ukpokiti Field Channel Complex, Oml 108, Offshore Nigeria, Northwestern Niger Delta, Toby Latwan Stewart

LSU Master's Theses

Detailed seismic stratigraphic analyses and mapping show that a well defined Ukpokiti Field Channel complex (late Miocene) found on the up-thrown side of a major back-to-back fault system in the West Niger delta inner-continental shelf probably formed during a single eustatic fall. The channel (>500 msec, 10 km wide) shows several tributaries entering the trunk axis from what was probably a surface of subaerial exposure. Slumping is prominent on the north flank of the trunk channel. No channel unconformity is evident in the down-thrown block. This investigation seeks to resolve the lack of down-dip correlative seismic expression across the …


Review Of Spokane River Model For Washington Department Of Ecology, Chris Berger, Robert Leslie Annear, Scott A. Wells Jan 2004

Review Of Spokane River Model For Washington Department Of Ecology, Chris Berger, Robert Leslie Annear, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

This memorandum discusses changes made to the Spokane River model calibration since the original calibration of the model discussed in the following reports: Annear et al. (2001), Berger at al. (2002), Slominski et al. (2002), and Berger et al. (2003). The first group of refinements was made by the Washington Department of Ecology. Additional changes were made by Portland State University (PSU) and were discussed in this report along with the results of two alternative calibrations. The last section displays the original calibration results from Berger et al. (2003) as a basis for comparison to the changes made by Ecology …


Willamette River Basin Temperature Tmdl Model: Boundary Conditions And Model Setup, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells Jan 2004

Willamette River Basin Temperature Tmdl Model: Boundary Conditions And Model Setup, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …


Nature And Dynamics Of Late Miocene/Early Pliocene Ice-Sheet Grounding Events On The Pacific Margin Of The Antarctic Pennisula Outer Continental Shelf, David C. Egan Jan 2004

Nature And Dynamics Of Late Miocene/Early Pliocene Ice-Sheet Grounding Events On The Pacific Margin Of The Antarctic Pennisula Outer Continental Shelf, David C. Egan

LSU Master's Theses

Package-3 unconformities identified by Bart and Anderson (1995) were mapped to evaluate their glacial unconformity interpretation using a regional grid of single channel seismic data from the Antarctic Peninsula outer continental shelf. Detailed correlations show many crosscutting relationships within Package 3 such that the unconformities and units they bound are not regionally continuous across the margin. Comparison of Package-3 unconformities with the modern bathymetry reveals that cross-shelf trough and bank morphology is absent, which indicates that ice streams probably did not exist on the shelf during Package-3 time. On the continental shelf, only the middle part of Package 3 is …


Migmatization Of Archean Aluminous Metasediments From The Eastern Beartooth Mountains, Montana, U.S.A., Andrew T. Maas Jan 2004

Migmatization Of Archean Aluminous Metasediments From The Eastern Beartooth Mountains, Montana, U.S.A., Andrew T. Maas

LSU Master's Theses

Geothermobarometry, mineral compositions and textures, and thermodynamic models suggest biotite dehydration melting occurred in the peraluminous rocks of the eastern Beartooth Mountains. These Archean metapelitic migmatites are metatexites and diatexites, and have typical metamorphic assemblages of Qtz + Pl + Kfs + Bt + Sil +/- Grt +/- Crd. The subsequent in situ crystallization of the magma derived from the biotite dehydration created migmatitic leucosomes in the rocks. These leucosomes are primarily composed of quartz, plagioclase and potassium feldspar. Water derived from the dehydration of biotite was dissolved in the melted phase. Crystallization of the magma reintroduced this water to …


Overlap Zones, Growth Faults, And Sedimentation: Using High Resolution Gravity Data, Livingston Parish, La, Carrie Alison Cazes Jan 2004

Overlap Zones, Growth Faults, And Sedimentation: Using High Resolution Gravity Data, Livingston Parish, La, Carrie Alison Cazes

LSU Master's Theses

In south Louisiana, parallel to the coast of the Gulf of Mexico, are belts of east-to-west trending, listric-normal faults with associated contemporaneous sedimentation and fault movement. The Tepetate-Baton Rouge Fault system in south-central Louisiana contains individual fault segments which are arcuate and overlap each other in map view, as seen on LiDAR data. Gravity survey data, with a sample spacing of 20 to 50 m, was collected across normal fault scarps. Structural ramps may form in the area between overlapping normal fault segments creating an east-to-west gradient. This gradient change may divert streams and provide areas for coarse-grained sediments to …


A Comparison Of A High-Resolution Survey And A Three-Dimensional Seismic Survey In A Feature-Rich Region Of The Green Canyon Area, Gulf Of Mexico, Bruce Miles Samuel Jan 2004

A Comparison Of A High-Resolution Survey And A Three-Dimensional Seismic Survey In A Feature-Rich Region Of The Green Canyon Area, Gulf Of Mexico, Bruce Miles Samuel

LSU Master's Theses

Recent advances in Autonomous Underwater Vehicle (AUV) technology have revolutionized the positioning and accuracy of high-resolution deep sea mapping tools. Geologic hazard and engineering surveys by AUV’s are producing high-resolution data sets of a quality that has never before been seen. Three-dimensional (3D) seismic data, though traditionally used for only deep subsurface mapping of large areas, is now being reprocessed at a higher resolution and utilized in well site investigations and geologic hazard assessments. This study makes a comparison between a 3D seismic survey and an AUV high-resolution survey in order to determine the strengths and weaknesses of both of …


Potential Contaminants At A Dredged Spoil Placement Site, Charles City County, Virginia, As Revealed By Sequential Extraction, Jianwu Tang, G. Richard Whittecar, Karen H. Johannesson, W. Lee Daniels Jan 2004

Potential Contaminants At A Dredged Spoil Placement Site, Charles City County, Virginia, As Revealed By Sequential Extraction, Jianwu Tang, G. Richard Whittecar, Karen H. Johannesson, W. Lee Daniels

OES Faculty Publications

Backfills of dredged sediments onto a former sand and gravel mine site in Charles City County, VA may have the potential to contaminate local groundwater. To evaluate the mobility of trace elements and to identify the potential contaminants from the dredged sediments, a sequential extraction scheme was used to partition trace elements associated with the sediments from the local aquifer and the dredged sediments into five fractions: exchangeable, acidic, reducible, oxidizable, and residual phases. Sequential extractions indicate that, for most of the trace elements examined, the residual phases account for the largest proportion of the total concentrations, and their total …


Biospeleologists, Aldemaro Romero Jr. Jan 2004

Biospeleologists, Aldemaro Romero Jr.

Publications and Research

No abstract provided.


Foreland Basins: Lithospheric Flexure, Plate Strength And Regional Stratigraphy, John Londono Jan 2004

Foreland Basins: Lithospheric Flexure, Plate Strength And Regional Stratigraphy, John Londono

LSU Doctoral Dissertations

Foreland basin subsidence through time is reproduced in this study, as the flexure of an elastic beam in an inviscid fluid under the vertical stress, caused by discrete-distributed loads. Thus, seismostratigraphic data from the Timor Sea peripheral foreland basin, in northwestern Australia, and the Putumayo retroarc foreland basin in the Colombian Andes, are forward modeled, at chronostratigraphic intervals, to assess the evolving geodynamic conditions of the basins. Results show that the accommodation in foreland basins varies as the depositional basement is vertically adjusted according to the regionally isostatic compensation of the lithosphere. Distributed tectonic (thrust belts) and sedimentary loads that …


West Antarctic Ice Stream Discharge Variability: Mechanism, Controls, And Pattern Of Grounding Line Retreat, Christina L. Hulbe, Mark A. Fahnestock Jan 2004

West Antarctic Ice Stream Discharge Variability: Mechanism, Controls, And Pattern Of Grounding Line Retreat, Christina L. Hulbe, Mark A. Fahnestock

Geology Faculty Publications and Presentations

West Antarctic ice streams show pronounced flow variability in their downstream reaches, with changes stranding formerly fast-flowing ice and redirecting discharge. A simple model, in which the temperature gradient in basal ice provides control of fast sliding in the downstream reach, can explain this behavior. Downstream thinning steepens the temperature gradient near the bed, increasing upward heat flow and the tendency toward basal freezing. The basal temperature gradient is steepest and the tendency toward basal freezing the strongest in ice that has experienced the most rapid downstream thinning, that is, the fastest-flowing ice. The most ?successful? rapid outflows are regions …


Catastrophic Ice Shelf Breakup As The Source Of Heinrich Event Icebergs, Christina L. Hulbe, D. R. Macayeal, George H. Denton, Johan Kleman, Thomas Lowell Jan 2004

Catastrophic Ice Shelf Breakup As The Source Of Heinrich Event Icebergs, Christina L. Hulbe, D. R. Macayeal, George H. Denton, Johan Kleman, Thomas Lowell

Geology Faculty Publications and Presentations

Heinrich layers of the glacial North Atlantic record abrupt widespread iceberg rafting of detrital carbonate and other lithic material at the extreme-cold culminations of Bond climate cycles. Both internal (glaciologic) and external (climate) forcings have been proposed. Here we suggest an explanation for the iceberg release that encompasses external climate forcing on the basis of a new glaciological process recently witnessed along the Antarctic Peninsula: rapid disintegrations of fringing ice shelves induced by climate-controlled meltwater infilling of surface crevasses. We postulate that peripheral ice shelves, formed along the eastern Canadian seaboard during extreme cold conditions, would be vulnerable to sudden …


Effects Of Low Tide Rainfall On Intertidal Zone Material Cycling, Raymond Torres, Miguel A. Goni, George Voulgaris, Charles R. Lovell, James T. Morris Jan 2004

Effects Of Low Tide Rainfall On Intertidal Zone Material Cycling, Raymond Torres, Miguel A. Goni, George Voulgaris, Charles R. Lovell, James T. Morris

Faculty Publications

Sediment transport by rainfall-runoff processes is well documented for terrestrial landscapes but few studies have focused on rainfall-runoff effects in intertidal areas. Here we present geochemical analyses performed on sediment samples collected during low tide irrigation experiments, and tidal channel turbidity measurements taken during natural rainfall over North Inlet Marsh, South Carolina. Order of magnitude approximations indicate that a single 10 minute storm may entrain 8-15% of the local annual average sediment accumulation. This rainfall-entrained material is enriched in organic nitrogen and marine algal matter, and therefore of high nutritional quality.


Semianalytical Solutions For Stream Depletion In Partially Penetrating Streams, Xunhong Chen, Yanfeng Yin Jan 2004

Semianalytical Solutions For Stream Depletion In Partially Penetrating Streams, Xunhong Chen, Yanfeng Yin

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Review Of Geologic Factors Affecting Underground Limestone Mining In The U.S. And An Overview Of Underground Limestone Mining In Nebraska, R. M. Joeckel Jan 2004

Review Of Geologic Factors Affecting Underground Limestone Mining In The U.S. And An Overview Of Underground Limestone Mining In Nebraska, R. M. Joeckel

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Federal Listing Of Prairie Grouse: Lessons From The Attwater’S Prairie Chicken, Michael Morrow, Terry A. Rossignol, Nova J. Silvy Jan 2004

Federal Listing Of Prairie Grouse: Lessons From The Attwater’S Prairie Chicken, Michael Morrow, Terry A. Rossignol, Nova J. Silvy

United States Geological Survey: Staff Publications

Considerable controversy has often surrounded proposals to confer official status (i.e., list) species under the authority of the Endangered Species Act (ESA) of 1973 as amended or its precursors. Recent proposals to list the lesser prairie-chicken (Tympanuchus pallidicinctus), the western sage grouse (Centrocercus urophasianus phaios), and the Gunnison sage grouse (C. minimus) were met with strong opposition by those concerned with prospects of an increased regulatory environment associated with such an action. The Attwater's prairie-chicken (T. cupido attwateri) was one of the first species listed under The Endangered Species Conservation Act of …


History Of Greater Sage-Grouse In The Dakotas: Distribution And Population Trends, Joe T. Smith, Lester D. Flake, Kenneth F. Higgins, Gerald D. Kobriger Jan 2004

History Of Greater Sage-Grouse In The Dakotas: Distribution And Population Trends, Joe T. Smith, Lester D. Flake, Kenneth F. Higgins, Gerald D. Kobriger

United States Geological Survey: Staff Publications

The greater sage-grouse (Centrocercus urophasianus) has declined throughout its range and its status is of major concern to federal, state, and provincial wildlife agencies. We collected information on current and historical greater sage-grouse distribution and lek activity in western North and South Dakota. A steady decline in lek attendance by males occurred over the entire recorded period in North Dakota (1951-2002) and South Dakota (1972-2002). There was no apparent change in numbers of known active leks due to discovery of new leks, but there was an abandonment of regions once occupied by active leks.


The History Of Recent Limnological Changes And Human Impact On Upper Klamath Lake, Oregon, J. Platt Bradbury, Steven M. Colman, Richard L. Reynolds Jan 2004

The History Of Recent Limnological Changes And Human Impact On Upper Klamath Lake, Oregon, J. Platt Bradbury, Steven M. Colman, Richard L. Reynolds

United States Geological Survey: Staff Publications

Hypereutrophic Upper Klamath Lake has been studied for almost 50 years to evaluate the nature, cause, and effects of its very productive waters. Mitigation of undesirable effects of massive cyanobacterial blooms requires understanding their modern causes as well as their history. Knowledge of the pre-settlement natural limnology of this system can provide guidelines for lake restoration and management of land and water use strategies to maximize the benefits of this aquatic resource. This investigation uses a paleolimnological approach to document the nature and chronology of limnological and biological changes in Upper Klamath Lake for the past 200 years, covering the …


Geochemical Cycles In Sediments Deposited On The Slopes Of The Guaymas And Carmen Basins Of The Gulf Of California Over The Last 180 Years, Walter E. Dean, Carol Prideb, Robert Thunell Jan 2004

Geochemical Cycles In Sediments Deposited On The Slopes Of The Guaymas And Carmen Basins Of The Gulf Of California Over The Last 180 Years, Walter E. Dean, Carol Prideb, Robert Thunell

United States Geological Survey: Staff Publications

Sediments deposited on the slopes of the Guaymas and Carmen Basins in the central Gulf of California were recovered in two box cores. Q-mode factor analyses identified detrital-clastic, carbonate, and redox associations in the elemental composition of these sediments. The detrital-clastic fraction appears to contain two source components, a more mafic component presumably derived from the Sierra Madre Occidental along the west coast of Mexico, and a more felsic component most likely derived from sedimentary rocks (mostly sandstones) of the Colorado Plateau and delivered by the Colorado River. The sediments also contain significant siliceous biogenic components and minor calcareous biogenic …