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Articles 91 - 120 of 334
Full-Text Articles in Earth Sciences
Mapping The Volumetric Soil Water Content Of A California Vineyard Using High-Frequency Gpr Ground Wave Data, Susan Sharpless Hubbard, Katherine R. Grote, Yoram N. Rubin
Mapping The Volumetric Soil Water Content Of A California Vineyard Using High-Frequency Gpr Ground Wave Data, Susan Sharpless Hubbard, Katherine R. Grote, Yoram N. Rubin
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
An attempt was made to establish the utility of ground-penetrating radar (GPR) as a quick and noninvasive field tool for shallow soil water content estimates as a function of space and time. Initially, detailed studies of collocated data, with electromagnetic velocity estimates from GPR data compared to gravimetric measurements of water content and to soil testure were carried out. Using the procedures developed during the detailed studies, full grids of GPR data were collected over the entire site several times. Data obtained indicate that incorporation of multiple frequency GPR grids can provide high-resolution estimates of soil water content variations as …
Gravity Evidence For A Larger Limpopo Belt In Southern Africa And Geodynamic Implications, Rubeni T. Ranganai, Ali Basira H. Kampunzu, Estella A. Atekwana, B. K. Paya, J. G. King, D. I. Koosimile, Edgar H. Stettler
Gravity Evidence For A Larger Limpopo Belt In Southern Africa And Geodynamic Implications, Rubeni T. Ranganai, Ali Basira H. Kampunzu, Estella A. Atekwana, B. K. Paya, J. G. King, D. I. Koosimile, Edgar H. Stettler
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The Limpopo Belt of southern Africa is a Neoarchean orogenic belt located between two older Archean provinces, the Zimbabwe craton to the north and the Kaapvaal craton to the south. Previous studies considered the Limpopo Belt to be a linearly trending east-northeast belt with a width of ∼250 km and ∼600 km long. We provide evidence from gravity data constrained by seismic and geochronologic data suggesting that the Limpopo Belt is much larger than previously assumed and includes the Shashe Belt in Botswana, thus defining a southward convex orogenic arc sandwiched between the two cratons. The 2 Ga Magondi orogenic …
Satellite Imagery Proves Essential For Monitoring Erupting Aleutian Volcano, Kenneson Dean, Jonathan Dehn, Stephen R. Mcnutt, Christina Neal, Richard Moore, Dave Schneider
Satellite Imagery Proves Essential For Monitoring Erupting Aleutian Volcano, Kenneson Dean, Jonathan Dehn, Stephen R. Mcnutt, Christina Neal, Richard Moore, Dave Schneider
School of Geosciences Faculty and Staff Publications
Mt. Cleveland is one of more than 40 active volcanoes in Alaska that is monitored by the Alaska Volcano Observatory (AVO). It is located on the western half of Chuginadak, a remote and uninhabited island in the east central Aleutians that lies 1526 km southwest of Anchorage. The closest inhabited community, Nikolski, is 75 km to the east on Umnak Island (Figure 1). Mt. Cleveland erupted explosively on 19 February and on 11 and 19 March 2001. Because the volcano is not yet monitored with seismic, deformation, or other geophysical instruments, satellite imagery was the only effective tool for detecting …
Early Warming Of Tropical South America At The Last Glacial-Interglacial Transition, G. O. Seltzer, D. T. Rodbell, P. A. Baker, Sherilyn C. Fritz, P. M. Tapia, H. D. Rowe, R. B. Dunbar
Early Warming Of Tropical South America At The Last Glacial-Interglacial Transition, G. O. Seltzer, D. T. Rodbell, P. A. Baker, Sherilyn C. Fritz, P. M. Tapia, H. D. Rowe, R. B. Dunbar
Department of Earth and Atmospheric Sciences: Faculty Publications
Glaciation in the humid tropical Andes is a sensitive indicator of mean annual temperature. Here, we present sedimentological data from lakes beyond the glacial limit in the tropical Andes indicating that deglaciation from the Last Glacial Maximum led substantial warming at high northern latitudes. Deglaciation from glacial maximum positions at Lake Titicaca, Peru/Bolivia (16°S), and Lake Junin, Peru (11°S), occurred 22,000 to 19,500 calendar years before the present, several thousand years before the Bølling-Allerød warming of the Northern Hemisphere and deglaciation of the Sierra Nevada, United States (36.5° to 38°N). The tropical Andes deglaciated while climatic conditions remained regionally wet, …
Thermochronological Evolution Of Calcite Formation At The Potential Yucca Mountain Repository Site, Nevada: Part 2 Fluid Inclusion Analyses And Upb Dating, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar
Thermochronological Evolution Of Calcite Formation At The Potential Yucca Mountain Repository Site, Nevada: Part 2 Fluid Inclusion Analyses And Upb Dating, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar
Publications (YM)
The presence of two-phase fluid inclusions in thin secondary mineral crusts at the potential Yucca Mountain nuclear waste repository has raised questions regarding the origin, timing, and temperature of past fluid flow through the repository horizon. The geologically recent passage of fluids with high temperatures would call into question the suitability of the site for the storage of high level nuclear waste. This study determined the thermal history of fluid flow through the site using fluid inclusion analyses and constrained the timing of thermal fluids by dating silica minerals spatially associated with the fluid inclusions using U-Pb techniques. Results provide …
Thermochronological Evolution Of Calcite Formation At The Proposed Yucca Mountain Repository Site, Nevada: Part 1, Secondary Mineral Paragenesis And Geochemistry, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar
Thermochronological Evolution Of Calcite Formation At The Proposed Yucca Mountain Repository Site, Nevada: Part 1, Secondary Mineral Paragenesis And Geochemistry, Jean S. Cline, Amy J. Smiecinski, Robert Bodnar
Publications (YM)
In the near future a decision will be made as to whether or not Yucca Mountain, 90 miles northwest of Las Vegas, Nevada is a suitable site for a permanent, underground, high level nuclear waste repository. A major factor in determining the suitability of Yucca Mountain as a repository is the potential for the site to be flooded by water during the regulatory lifetime. The current study was undertaken to examine the past fluid history at the site, to gain a better understanding of the possibility of flooding in the near geologic future. To estimate the past fluid flux into …
Geochemistry Of Atmospheric Aerosols Generated From Lava-Seawater Interactions, Francis J. Sansone, Claudia R. Benitez-Nelson, Joseph A. Resing, Eric H. Decarlo, Sue M. Vink, Jacqueline A. Heath, Barry J. Huebert
Geochemistry Of Atmospheric Aerosols Generated From Lava-Seawater Interactions, Francis J. Sansone, Claudia R. Benitez-Nelson, Joseph A. Resing, Eric H. Decarlo, Sue M. Vink, Jacqueline A. Heath, Barry J. Huebert
Faculty Publications
[1] Trace elements were measured in the aerosol plume produced by lava‐seawater interactions along the shoreline of Kilauea volcano, Hawaii. Plume concentrations were normalized relative to Hawaiian basalt composition and showed a linear log‐log co‐variation with their emanation coefficient (an indicator of element volatility). Normalized aerosol concentrations also consistently covaried with corresponding normalized concentrations in dilute fumarolic gas from Kilauea volcano and fumarolic gas condensates from Kudryavy and Merapi volcanoes, despite different mechanisms of element volatilization. Conservatively estimated regional ocean deposition rates of Cu, Cd, Ni, Pb, Mn, Zn, Fe and P were >50 times background rates. Thus, upper ocean …
Communicator-In-Chief: Presidential Use Of Television Past, Present, And Future, Jenna Wasson
Communicator-In-Chief: Presidential Use Of Television Past, Present, And Future, Jenna Wasson
Honors Theses
This thesis seeks to determine how television has changed as a communication medium for presidents over the past half century. An evaluation of the evolving ways presidents use television to communicate with and to build support from the American people has been conducted. Presidential communication strategies have been identified by drawing primarily from primary sources written by presidents and White House staff. Television technology and the television audience have changed over the years. Presidents have taken a more pro-active, aggressive role in their efforts to harness television for their own purposes. Why have these changes occurred? What impact have these …
Transport Of The Herbicide Atrazine On Suspended Sediments During A Spring Storm Event In Mammoth Cave, Kentucky, Michael Anderson
Transport Of The Herbicide Atrazine On Suspended Sediments During A Spring Storm Event In Mammoth Cave, Kentucky, Michael Anderson
Masters Theses & Specialist Projects
This study examines the transport of atrazine, an herbicide used in Kentucky to control grassy and broad-leaf weeds in corn fields, on suspended sediments. Atrazine is a known carcinogen and endocrine disruptor and has been shown to be toxic at low environmental concentrations. Atrazine has the capacity to adsorb to soil particles, which in karst areas such as those found in south central Kentucky can be transported directly into the groundwater. Suspended sediments and water were collected from a well at the Hawkins River in Mammoth Cave National Park during a spring storm and tested for atrazine. Atrazine was found …
Bioavailability/Toxicity Of Iron From Aerobically Processed Organic Fertilizer, Stacey Marie Wilson
Bioavailability/Toxicity Of Iron From Aerobically Processed Organic Fertilizer, Stacey Marie Wilson
Undergraduate Honors Capstone Projects
For an undergraduate Honor's project, I worked under the direction of Dr. Jeffery Hall to determine the bioavailability and toxicity of iron from Milorganite® fertilizer, an aerobically processed organic fertilizer. The Milorganite® Company is a subsidiary of the Milwaukee Municipal Sewage District and produces a fertilizer of high iron content (approximately 5-7%). The high iron content has resulted in concern about the toxic potential, which until now was unknown. This thesis paper will explain iron chemistry, bioavailability, requirements, absorption, toxicity, and treatments, followed by a description of fertilizer types and contents. This will be followed by a description and reasoning …
Evolution Of A Miocene-Pliocene Low-Angle Normal-Fault System In The Southern Bannock Range, Southeast Idaho, Stephanie M. Carney
Evolution Of A Miocene-Pliocene Low-Angle Normal-Fault System In The Southern Bannock Range, Southeast Idaho, Stephanie M. Carney
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Geologic mapping, basin analysis, and tephrochronologic analysis in the Clifton quadrangle of southeast Idaho indicates that the modern Basin-and-Range topography is only a few million years old and that the bulk of Cenozoic extension was accommodated by slip on an older low-angle normal-fault system, the Bannock detachment system. The detachment system was active between ~12 and < 4 Ma and accommodated ~50 % extension.
Cross-cutting relationships show that the master detachment fault, the Clifton fault, is the youngest low-angle normal fault of the system, was active at a low angle, and has not been rotated to a low-dip angle through time. Map patterns and relationships indicate that the …
Relationships Between Tributary Catchments, Valley-Bottom Width, Debris-Fan Area, And Mainstem Gradient On The Colorado Plateau: A Case Study In Desolation And Gray Canyons On The Green River, Caroline M. Elliott
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The alluvial forms of the rivers that drain the Colorado Plateau are a product of the water and sediment load that tributaries deliver to the trunk streams. Where the Green and Colorado Rivers cross structural barriers, narrow canyons have been incised. In the steep terrain adjacent to many of these canyons debris flows occur in the catchment basins of tributaries and deliver coarse sediment to the mainstem river corridor. Over time, debris flow deposits have aggraded in trunk stream valleys and created landforms known as debris fans. The sizes of these debris fans are related to the accommodation space available …
Geometry And Physical Properties Of The Chelungpu Fault, Taiwan, And Their Effect On Fault Rupture, Richard V. Heermance
Geometry And Physical Properties Of The Chelungpu Fault, Taiwan, And Their Effect On Fault Rupture, Richard V. Heermance
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Rupture of the Chelungpu fault during the September 21, 1999, 7.6 Mwearthquake in Taiwan caused a 90-Jr,m-long surface rupture with variable displacement along strike. Analysis of core from two holes drilled through the fault zone, combined with geologic mapping and detailed investigation from three outcrops, define the fault geometry and physical properties of the Chelungpu fault in its northern and southern regions. In the northern region, the fault dips 45-60° east parallel to bedding and consists of a narrow (1-20 cm) core of dark-gray, sheared clay gouge at the base of a 30-50 m zone of increased fracture …
Geology Of The Cuesta Ridge Ophiolite Remnant Near San Luis Obispo, California: Evidence For The Tectonic Setting And Origin Of The Coast Range Ophiolite, Cameron A. Snow
Geology Of The Cuesta Ridge Ophiolite Remnant Near San Luis Obispo, California: Evidence For The Tectonic Setting And Origin Of The Coast Range Ophiolite, Cameron A. Snow
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Cuesta Ridge ophiolite is one of the best-preserved remnants of mid-Jurassic ophiolite in California. Geologic mapping and petrologic studies show that it comprises (1) harzburgite mantle tectonite, (2) dunite-rich mantle transition zone (MTZ), (3) wehrlite and pyroxenite, (4) isotropic gabbro, (5) sheeted dike/sill complex, (6) volcanic rocks (7) late-stage dikes and flows, and (8) tuffaceous radiolarian chert.
The sheeted dike/sill complex is dominated by quartz diorite, with significant modal quartz and hornblende. The volcanic section is dominated by arc tholeiite and boninitic lavas. Boninites, with high MgO, Cr, and Ni comprise 40% of the volcanic rocks. Latestage dikes and …
Stratigraphy And Paleoecology Of The Morrison Formation, Como Bluff, Wyoming, Melissa V. Connely
Stratigraphy And Paleoecology Of The Morrison Formation, Como Bluff, Wyoming, Melissa V. Connely
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Morrison Formation at Como Bluff, Wyoming, has been historically known for containing a rich source of Late Jurassic vertebrate fossils. However, when collected, most of these fossils were not positioned into a stratigraphic or sedimentologic framework. Research shows that the Morrison Formation at Como Bluff can be divided into three members. These members can be identified by lithologic and paleontological characteristics. The lower Morrison members include the Windy Hill Member and the recently described Lake Como Member. The Windy Hill Member primarily contains near-shore marine sandstone. Megavertebrate fauna is lacking. The Lake Como Member contains illitic clay in red …
The Stratigraphic, Sedimentologic, And Paleogeographic Evolution Of The Eocene- Oligocene Grasshopper Extensional Basin, Southwest Montana, Joseph P. Matoush
The Stratigraphic, Sedimentologic, And Paleogeographic Evolution Of The Eocene- Oligocene Grasshopper Extensional Basin, Southwest Montana, Joseph P. Matoush
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Grasshopper basin, located in southwest Montana, is an east-tilted graben bounded by the listric Muddy-Grasshopper fault and the Meriwether Lewis fault on the eastern and western margins of the basin, respectively. This basin contains a complex stratigraphy of intertonguing facies comprised of five unconformity-bounded sequences of Tertiary alluvial, flu vial, deltaic, and lacustrine sedimentary and volcanic rocks. Sequence 1 consists of the Challis volcanic Group (Middle Eocene). The sedimentary rocks of the Medicine Lodge beds (Late Eocene-Late Oligocene) represent sequence 2 and approximately 90% of the basin-fill within Grasshopper basin. Sequence 3 consists 11 of the Sedimentary Rocks of Everson …
Structural And Kinematic Evolution Of Eocene-Oligocene Grasshopper Extensional Basin, Southwest Montana, Julie C. Kickham
Structural And Kinematic Evolution Of Eocene-Oligocene Grasshopper Extensional Basin, Southwest Montana, Julie C. Kickham
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Grasshopper basin of southwest Montana is a complex east-dipping graben containing five unconformity-bounded sequences of Tertiary sedimentary rocks. The Eocene-Oligocene basin lies within the northern Rocky Mountain Basin and Range province. Geologic mapping in five and a half 7.5 minute quadrangles indicates that at least three distinct phases of extension characterize the Cenozoic tectonic evolution of Grasshopper basin from approximately 46 Ma to < Ma.
The significant phases of extension in Grasshopper basin were phases 1 and 3. During the first phase of extension (46-27 Ma) the nonplanar Muddy-Grasshopper fault was initiated and 90% of the basin fill was deposited. At …
Application Of Biophysical Data To An Unsupervised Classification To Map Ecoregional Boundaries In The Desert Southwest, Paxton R. Mcclurg
Application Of Biophysical Data To An Unsupervised Classification To Map Ecoregional Boundaries In The Desert Southwest, Paxton R. Mcclurg
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
An unsupervised classification was applied to continuous biophysical variables in an attempt to delineate ecoregional boundaries in the desert southwest. Output was then compared with ecoregions delineated by the Natural Resources Conservation Service (NRCS), the Environmental Protection Agency (EPA), and the Forest Service at the national level. An attempt was made to use the same biophysical variables for input into the unsupervised classification as was emphasized by the various agencies with their ecoregional classifications at the desert level. Major constraints included data availability at such a large study area, data resolution, and data that were continuous. This eliminated categorical data …
A Macroterrain Landtype Association Classification Model For The Great Basin, Frank L. Dougher
A Macroterrain Landtype Association Classification Model For The Great Basin, Frank L. Dougher
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Three Macroterrain Landtype Association classification models were developed to stratify and categorize Utah's West Desert. These models approached terrain segmentation using an energy-flow paradigm from erosional to transitional to depositional landscape. One model was developed as a slope-backed deterministic model that used slope-threshold limits to discriminate between Landtype Associations. A second model was developed as a stochastic, training-data driven supervised classification, using comparative t-values to classify the landscape to the most similar landtype class. The third model was a probabilistic algorithm, which classified the landscape to the most probable class based on multiple iterations of the stochastic model. These …
Sedimentology, Facies Architecture, And Reservoir Characterization Of Lacustrine Rocks, Eocene Green River And Colton Formations, Uinta Basin, Utah, Andrew W. Taylor
Sedimentology, Facies Architecture, And Reservoir Characterization Of Lacustrine Rocks, Eocene Green River And Colton Formations, Uinta Basin, Utah, Andrew W. Taylor
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Outcrop and petrographic studies of the Eocene Green River and Colton formations in the Uinta basin, Utah, document the facies architecture and heterogeneity characteristic of lacustrine reservoirs. A southwest-northeast transect of Eocene strata in the Uinta basin records three main marginal lacustrine depositional environments: fluvial, deltaic, and wave-dominated. Heterogeneity exists between and within individual depositional systems.
Reservoir rocks of Outcrops One and Two (the flu vial facies of the Colton Formation and the deltaic facies of the Green River Formation, respectively) consist of 2 to 18 m thick lenticular, tabular, or undulatory channel-fill, distributary channel, and distributary mouth bar deposits …
Land Usage Impacts On Springhead Salamander Populations, At Callaway Extended Properties, Harris County, Georgia, Neil Allen Pearce
Land Usage Impacts On Springhead Salamander Populations, At Callaway Extended Properties, Harris County, Georgia, Neil Allen Pearce
Theses and Dissertations
Recent scientific studies have indicated that anrphibian populations appear to be declining in many areas of the world or exhibiting local population fluctuations. Some of the reasons given for this population decline are associated with land usage, and the negative biological impacts of many forms of land management practices. A study was conducted at the Callaway Gardens Extended Properties in Pine Mountain Georgia which compared the local aquatic salamander populations of five spring -fed streams in the Cason J. Callaway Memorial Forest, and five spring-fed streams in the Lower Valley Area. Using a cat ch-per-unit -effort sampling methodology, a comparison …
Using Gis And Land Use Data To Select Candidate Reference Sites For Stream Bioassessment, John Robert Olson
Using Gis And Land Use Data To Select Candidate Reference Sites For Stream Bioassessment, John Robert Olson
Theses and Dissertations
GIS was used to select candidate reference sites in Georgia to characterize the reference condition by sub-ecoregion for a rapid bioassessment of streams statewide. Instead of relying on best professional judgment or previous knowledge of a limited number of sites, we performed an objective evaluation of cumulative impact on all catchments using land use data sets. These included road and impoundment data from DLGs and Multi-Resolution Land use Consortium data. Land use impairment was measured as percentages of forest, urban, pasture, row crops, and barren area for both the entire catchment and for 10, 40, and 130-m riparian buffers, road …
Profitable And Productive Farming Systems For Management Of Nolba Catchment, B R. Eastough, Nolba Focus Catchment Group
Profitable And Productive Farming Systems For Management Of Nolba Catchment, B R. Eastough, Nolba Focus Catchment Group
Resource management technical reports
Summary of the main points covered at each of the several workshop and two demonstrations by the Nolba Catchment Group, Western Australia. The areas addressed include: low recharge farming systems; impact on the environment of integrated weed management; management of organic matter in soils within the catchment; dune stabilisation and groundwater hydrology.
Temporal Variation Of Seismic B-Values Beneath Northeastern Japan Island Arc, Aimin Cao, Stephen S. Gao
Temporal Variation Of Seismic B-Values Beneath Northeastern Japan Island Arc, Aimin Cao, Stephen S. Gao
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Analysis of a high quality seismic catalog reveals that the average of seismic b-values in the crust beneath most part of northeastern Japan island arc decreased from 0.86 between 1984 and 1990, to 0.73 between 1991 and 1995. The two areas with the largest decrease are found to be in the same areas where the coupling between the North American and the Pacific plates is the highest, as suggested by a recent geodetic study. In the same time period, the annual seismic moment release increased by 10 times. In addition, there seems to be a corresponding increase in volcanic activities …
Gpr Monitoring Of Volumetric Water Content In Soils Applied To Highway Construction And Maintenance, Katherine R. Grote, Susan Sharpless Hubbard, Yoram N. Rubin
Gpr Monitoring Of Volumetric Water Content In Soils Applied To Highway Construction And Maintenance, Katherine R. Grote, Susan Sharpless Hubbard, Yoram N. Rubin
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
An overview is given on two experiments, a controlled pit study and a transportation application in subasphalt soils. Both experiments show that common-offset ground-penetrating radar (GPR) reflection data can be used to estimate θv to a high degree of accuracy. The methodology developed in these two experiments provides a technique for obtaining quick, noninvasive, accurate, and high-resolution estimates of θv.
Mantle Discontinuities Beneath Southern Africa, Stephen S. Gao, Paul G. Silver, Kelly H. Liu, Kaapvaal Seismic Group
Mantle Discontinuities Beneath Southern Africa, Stephen S. Gao, Paul G. Silver, Kelly H. Liu, Kaapvaal Seismic Group
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Seismic velocity discontinuities within the top 1000 km of the Earth beneath southern Africa are imaged by stacking about 1300 source-normalized broadband seismograms recorded by the Southern African Seismic Experiment. The Moho, 410, and 660 kilometer discontinuities are clearly detected. The mean mantle transition zone thickness is 245 km, essentially the same as the global average, suggesting that the transition zone is not anomalously warm. Thus, the lower-mantle 'African Superplume' beneath our study area has no discernible effect on transition zone temperature and is consequently confined to the lower mantle. Variations in transition zone thickness appear to be related to …
The Lacustrine Carbon Cycle As Illuminated By The Waters And Sediments Of Two Hydrologically Distinct Headwater Lakes In North-Central Minnesota, U.S.A., Walter E. Dean, Antje Schwalb
The Lacustrine Carbon Cycle As Illuminated By The Waters And Sediments Of Two Hydrologically Distinct Headwater Lakes In North-Central Minnesota, U.S.A., Walter E. Dean, Antje Schwalb
United States Geological Survey: Staff Publications
The accumulation rates of CaCO3 and organic carbon (OC) in lake sediments are delicately balanced between production in the epilimnion and destruction in the hypolimnion. The cycling of these two forms of carbon makes a ‘‘carbon pump’’ that greatly affects the biogeochemical cycles of other elements. To further understand these biogeochemical dynamics, the lakes, streams, and wetlands of the Shingobee River headwater area of north-central Minnesota have been subjected to intensive hydrologic and biogeochemical studies. Williams Lake, situated close to the highest point in the regional flow system, is hydrologically closed, with no surface inlet or outlet, and ground …
Physical And Chemical Heterogeneity In The Subsurface: Spatial Distribution Of Transport Parameters And Their Relation To Depositional Processes, Dana Divine
Conservation and Survey Division: Faculty and Staff Publications
This thesis consists of two parts. The goal of first section is to better understand the influence of heterogeneity on contaminant transport. This objective is approached by quantifying the heterogeneity that may have affected transport of the Stanford-Waterloo tetrachloroethene (PCE) plume. Specifically, I determine the statistical distribution of the PCE sorption distribution coefficient (Kd) at Canadian Forces Base Borden, identify the spatial distribution of Kd, and determine the cross-correlation structure between PCE Kd and permeability (k). The results show that Kd is not lognormally distributed, and that variance is insufficient to …
The Drought Monitor, Mark D. Svoboda, Doug Lecomte, Mike Hayes, Richard Heim, Karin Gleason, Jim Angel, Brad Rippey, Rich Tinker, Mike Palecki, David Stooksbury, David Miskus, Scott Stephens
The Drought Monitor, Mark D. Svoboda, Doug Lecomte, Mike Hayes, Richard Heim, Karin Gleason, Jim Angel, Brad Rippey, Rich Tinker, Mike Palecki, David Stooksbury, David Miskus, Scott Stephens
National Drought Mitigation Center: Faculty Publications
There is a need for improved drought monitoring and assessment methods in the United States. Drought is the most costly natural disaster [Federal Emergency Management Agancy (FEMA 1995; Wilhite 2000)], but it is often neglected by developers of assessment and forecast products. Drought is more nebulous than other disasters and does not lend itself to traditional assessments or forecast methods. Its relatively slow onset and the complexity of its impacts are reasons for the new assessment methodology. Improvements in drought monitoring and forecasting techniques will allow for better preparation, lead to better management practices, and reduce the vulnerability of society …
Late-Quaternary Lowstands Of Lake Titicaca: Evidence From High-Resolution Seismic Data, Karin D'Agostino, Geoffrey Seltzer, Paul A. Baker, Sherilyn C. Fritz, Robert Dunbar
Late-Quaternary Lowstands Of Lake Titicaca: Evidence From High-Resolution Seismic Data, Karin D'Agostino, Geoffrey Seltzer, Paul A. Baker, Sherilyn C. Fritz, Robert Dunbar
Department of Earth and Atmospheric Sciences: Faculty Publications
Approximately 600 km of high-resolution seismic reflection data were collected to investigate the late-Quaternary stratigraphic development of Lake Titicaca. The focus of this report is on two seismic sequence boundaries, which are interpreted as erosional surfaces formed at times of low lake level. The younger erosional surface occurs as much as 90 m below the present lake level and up to 8 m below the present sediment–water interface. This erosional surface is interpreted to be coeval with a well-documented early- to mid-Holocene lowstand, dated between ~8,000 and 3,600 cal yr BP. An earlier and previously unknown erosional surface occurs at …