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Articles 31 - 60 of 96
Full-Text Articles in Geomorphology
Sulfur (34S/32S) Isotope Composition Of Gypsum And Implications For Deep Cave Formation On The Nullarbor Plain, Australia, Matej Lipar, Mateja Ferk, Sonja Lojen, Milo Barham
Sulfur (34S/32S) Isotope Composition Of Gypsum And Implications For Deep Cave Formation On The Nullarbor Plain, Australia, Matej Lipar, Mateja Ferk, Sonja Lojen, Milo Barham
International Journal of Speleology
Large deep caves with little relation to surface topography are distinctive karst features on the Nullarbor Plain of Australia. The presence of gypsum deposits and chemoautotrophic bacteria within the caves have been suggested as evidence for cave formation and (or) enlargement via sulfuric acid speleogenesis. To test this hypothesis, the stable sulfur isotope compositions (δ34S) of both cave gypsum and surface gypsum were measured. Analyses yielded relatively high, positive δ34S values from both cave gypsum and surface gypsum, arguing against gypsum genesis via microbial chemoautotrophy, and more broadly, sulfuric acid speleogenesis. Instead, the gypsum is interpreted …
Evidence For Subsurface Origin Of Boulder Caves, Roofed Slots And Boulder-Filled Canyons (Broumov Highland, Czechia), Filip Duszyński, Kacper Jancewicz, Piotr Migoń
Evidence For Subsurface Origin Of Boulder Caves, Roofed Slots And Boulder-Filled Canyons (Broumov Highland, Czechia), Filip Duszyński, Kacper Jancewicz, Piotr Migoń
International Journal of Speleology
The backslope of a sandstone cuesta in the Broumov Highland (Czechia) is cut by a complex network of canyons. Long sections of canyons have thick boulder fills which are difficult to reconcile with simple rock fall and talus development scenario. Boulder caves occur within these fills and their lowermost parts are drained by streams that evacuate fine loose sandy material produced by weathering and mechanical erosion. These boulder fills are explained as largely in situ, residual features, left after subsurface selective disintegration of rock mass, mainly joint-guided, and removal of grains by underground water. Evacuation of fines leaves voids …
County-Wide Assessment Of Irrigation Expansion On Air Temperature, Humidity And Evapotranspiration Rates In Nebraska, 1979-2015, Jozsef Szilagyi
County-Wide Assessment Of Irrigation Expansion On Air Temperature, Humidity And Evapotranspiration Rates In Nebraska, 1979-2015, Jozsef Szilagyi
Conservation and Survey Division: Faculty and Staff Publications
Total irrigated land area has been expanding in Nebraska over the last 40 years, propelling the state into a leading position within the US in terms of irrigated acreages. Typically, those counties which display the largest degree of irrigation development had a significant portion of their land area already irrigated in 1978. Large-scale irrigation in Nebraska affects its atmospheric environment. During the typical irrigation season of May to August, counties with the largest rate of irrigation expansion have cooled by about 0.2 – 0.3 °F per decade in the summer months of June, July and August, while counties with the …
Coupled Barrier Island Shoreline And Shoreface Dynamics, Benjamin S. Beasley
Coupled Barrier Island Shoreline And Shoreface Dynamics, Benjamin S. Beasley
LSU New Orleans Theses and Dissertations
In Louisiana, barrier islands are undergoing morphological change driven by high rates of relative sea-level rise and interior wetland loss. Previous works utilized historical region-scale bathymetry and shoreline change analyses to assess coastal evolution. However, more localized assessments considering the role of sediment transport processes in regional evolution are lacking. This is essential to predicting coastal change trajectories and allocating limited sand resources for nourishment. Using bathymetric and shoreline data, 100-m spaced shore-normal transects were created to track meter-scale elevation change for 1880s, 1930s, 1980s, 2006, and 2015. An automated framework was used to quantify and track parameters such as …
Quantifying The Environmental Performance Of A Stream Habitat Improvement Project, Cody Morse
Quantifying The Environmental Performance Of A Stream Habitat Improvement Project, Cody Morse
Master's Theses
River restoration projects are being installed worldwide to rehabilitate degraded river habitat. Many of these projects focus on stream habitat improvement (SHI), and an estimated 60%of the 37,000 projects listed in the National River Restoration Science Synthesis Program focus on SHI for salmon and trout species. These projects frequently lack a sufficient monitoring program or account for the environmental costs associated with SHI. The present study used life cycle assessment (LCA) techniques and topographic effectiveness monitoring to quantify environmental costs on the basis of geomorphic change. This methodology was a novel approach to assessing the cost-benefit relationship of SHI. To …
Spatial And Temporal Trends Of Mining-Related Lead-Zinc Sediment Contamination, Galena River Watershed, Sw Wisconsin-Nw Illinois, Dylan Alexander King
Spatial And Temporal Trends Of Mining-Related Lead-Zinc Sediment Contamination, Galena River Watershed, Sw Wisconsin-Nw Illinois, Dylan Alexander King
Graduate Theses/Dissertations
Alluvial sediments within the Galena River Watershed were severely contaminated with heavy metals by historical zinc (Zn) and lead (Pb) mining operations during the early 1800s until 1979. Since the mines closed, there have been efforts to remediate on-site mine waste. However, the effectiveness of these efforts to reduce metal concentrations in stream sediments is unknown. This study compares present-day (2017) contamination trends in the Galena River Watershed to trends reported 25 years ago. A total of 415 sediment/soil samples were collected and analyzed using X-ray florescence spectrometry to determine sediment metal concentrations. The highest concentrations of zinc measured were …
Coastal Wetland Dynamics Under Sea-Level Rise And Wetland Restoration In The Northern Gulf Of Mexico Using Bayesian Multilevel Models And A Web Tool, Tyler Hardy
Master's Theses
There is currently a lack of modeling framework to predict how relative sea-level rise (SLR), combined with restoration activities, affects landscapes of coastal wetlands with uncertainties accounted for at the entire northern Gulf of Mexico (NGOM). I developed such a modeling framework – Bayesian multi-level models to study the spatial pattern of wetland loss in the NGOM, driven by relative RSLR, vegetation productivity, tidal range, coastal slope, and wave height – all interacting with river-borne sediment availability, indicated by hydrological regimes. These interactions have not been comprehensively investigated before. I further modified this model to assess the efficacy of restoration …
Analysis Of The Parkway Drive Landslide, North Salt Lake, Ut, Brianna V. Hill
Analysis Of The Parkway Drive Landslide, North Salt Lake, Ut, Brianna V. Hill
All Graduate Plan B and other Reports, Spring 1920 to Spring 2023
On August 5th, 2014, a hillside failed behind a North Salt Lake City, UT neighborhood threatening several homes. Aerial Photography, Digital Elevation Models (DEM), geochemistry, rain gage and seismic data were used to test the influence of contributing factors in this landslide failure. Aerial photographs available from 1993 to present were examined for signs of tension cracks suggesting impending ground motion, as well as documentation of human modification along the hillslope. Repeat DEM analysis of elevation and slope of the hillside before and after the slide were examined to characterize the pre-failure hillslope and subsequent landslide. Geochemical analyses …
Geomorphology Of Icy Debris Fans: Delivery Of Ice And Sediment To Valley Glaciers Decoupled From Icecaps, R. Craig Kochel, Jeffrey M. Trop, Robert W. Jacob
Geomorphology Of Icy Debris Fans: Delivery Of Ice And Sediment To Valley Glaciers Decoupled From Icecaps, R. Craig Kochel, Jeffrey M. Trop, Robert W. Jacob
Faculty Journal Articles
The pace and volume of mass flow processes contributing ice and sediment to icy debris fans (IDFs) were documented at sites in Alaska and New Zealand by integrating field observations, drone and time-lapse imagery, ground penetrating radar, and terrestrial laser scanning. Largely unstudied, IDFs are supraglacial landforms at the mouths of bedrock catchments between valley glaciers and icecaps. Time-lapse imagery recorded 300–2300 events reaching 15 fans during intervals from nine months to two years. Field observations noted hundreds of deposits trapped within catchments weekly that were later remobilized onto fans. Deposits were mapped on images taken three to four times …
Old And Recent Processes In A Warm And Humid Desert Hypogene Cave: ‘A’Rak Na‘Asane, Israel, Amos Frumkin, Shlomi Aharon, Uri Davidovich, Boaz Langford, Yoav Negev, Micka Ullman, Anton Vaks, Shemesh Ya‘Aran, Boaz Zissu
Old And Recent Processes In A Warm And Humid Desert Hypogene Cave: ‘A’Rak Na‘Asane, Israel, Amos Frumkin, Shlomi Aharon, Uri Davidovich, Boaz Langford, Yoav Negev, Micka Ullman, Anton Vaks, Shemesh Ya‘Aran, Boaz Zissu
International Journal of Speleology
Recent environmental processes are studied in ʻA’rak Naʻasane Cave at the northern Judean Desert, Israel. The outer zone of the cave is heavily influenced by the outside environment through a large entrance, facilitating entry of air flow, fauna and humans, with minor cave-forming modifications. Conversely, the inner cave sustains humid and warm conditions, favoring modifications by condensation corrosion of convective air flow, associated with deposition of popcorn speleothems at the lower parts of dissolution pockets. The warm humid air of the inner cave may be associated with an underlying thermal water table. Active condensation corrosion is decreasing, possibly because of …
Unconfined Hypogene Evaporite Karst: West Texas And Southeastern New Mexico, Usa, Kevin W. Stafford, Jon T. Ehrhart, Adam F. Majzoub, Jessica M. Shields, Wesley A. Brown
Unconfined Hypogene Evaporite Karst: West Texas And Southeastern New Mexico, Usa, Kevin W. Stafford, Jon T. Ehrhart, Adam F. Majzoub, Jessica M. Shields, Wesley A. Brown
International Journal of Speleology
Diverse karst phenomena occur throughout the Gypsum Plain where the Castile Formation crops out over ~1800 km2 in West Texas and southeastern New Mexico. Hypergene karst is extensive and widespread, while traditional hypogene karst manifestations (both caves and intrastratal dissolution) occur in high frequency in the western outcrop region where surface denudation has been the greatest so as to induce surficial breaching. Unconfined hypogene karst occurrences have been recently identified, including two general variations: 1) artesian-like discharge features; and 2) venting structures. Artesian-like discharge features arise at surficially-breached hypogene caves and through high permeability regions on the margins of …
Effects Of Natural And Anthropogenic Forcing On Marsh Channel Evolution, Jeremiah Robinson
Effects Of Natural And Anthropogenic Forcing On Marsh Channel Evolution, Jeremiah Robinson
LSU Master's Theses
Wetlands have many ecological and physical properties that are essential for coastal communities. These ecosystems sustain local economies, provide essential habitats, are a source of numerous ecological and biological services, and protect coastal populations from storms. Of the many wetland types, salt marshes are among the most vulnerable to environmental changes. Salt marshes quickly respond to natural and human-driven perturbations and their high rate of loss in the last century is cause for concern.
In this project the rate of marsh loss driven by channel widening was measured through a comparative analysis of modern high resolution images and historic aerial …
New Insights On Secondary Minerals From Italian Sulfuric Acid Caves, Ilenia M. D'Angeli, Cristina Carbone, Maria Nagostinis, Mario Parise, Marco Vattano, Giuliana Madonia, Jo De Waele
New Insights On Secondary Minerals From Italian Sulfuric Acid Caves, Ilenia M. D'Angeli, Cristina Carbone, Maria Nagostinis, Mario Parise, Marco Vattano, Giuliana Madonia, Jo De Waele
International Journal of Speleology
Sulfuric acid minerals are important clues to identify the speleogenetic phases of hypogene caves. Italy hosts ~25% of the known worldwide sulfuric acid speleogenetic (SAS) systems, including the famous well-studied Frasassi, Monte Cucco, and Acquasanta Terme caves. Nevertheless, other underground environments have been analyzed, and interesting mineralogical assemblages were found associated with peculiar geomorphological features such as cupolas, replacement pockets, feeders, sulfuric notches, and sub-horizontal levels. In this paper, we focused on 15 cave systems located along the Apennine Chain, in Apulia, in Sicily, and in Sardinia, where copious SAS minerals were observed. Some of the studied systems (e.g., …
Extremely High Diversity Of Sulfate Minerals In Caves Of The Irazú Volcano (Costa Rica) Related To Crater Lake And Fumarolic Activity, Andrés Ulloa, Fernando Gázquez, Aurelio Sanz-Arranz, Jesús Medina, Fernando Rull, José María Calaforra, Guillermo E. Alvarado, María Martínez, Geoffroy Avard, J. Maarten De Moor, Jo De Waele
Extremely High Diversity Of Sulfate Minerals In Caves Of The Irazú Volcano (Costa Rica) Related To Crater Lake And Fumarolic Activity, Andrés Ulloa, Fernando Gázquez, Aurelio Sanz-Arranz, Jesús Medina, Fernando Rull, José María Calaforra, Guillermo E. Alvarado, María Martínez, Geoffroy Avard, J. Maarten De Moor, Jo De Waele
International Journal of Speleology
The caves of the Irazú volcano (Costa Rica), became accessible after the partial collapse of the NW sector of the Irazú volcano in 1994, offering the opportunity to investigate active minerogenetic processes in volcanic cave environments. We performed a detailed mineralogical and geochemical study of speleothems in the caves Cueva los Minerales and Cueva Los Mucolitos, both located in the northwest foothills of the main crater. Mineralogical analyses included X-ray diffraction (XRD) and Raman spectroscopy, while geochemical characterization used Energy Dispersive X-ray spectroscopy (EDX) coupled to Scanning Electron Microscopy (SEM). In addition, measurements of environmental parameters in the caves, …
Tectonic Controls On Alluvial Fan Dissection In The El Paso Mountains, Michael Thomas Gaffney
Tectonic Controls On Alluvial Fan Dissection In The El Paso Mountains, Michael Thomas Gaffney
Natural Resources Management and Environmental Sciences
The localized dissection of alluvial fans along the western El Paso Mountains is under question. A relatively minor, south dipping normal fault, previously unmentioned in scientific literature, cuts across Quaternary terraces and alluvial fans in the piedmont of the El Paso Mountains. The linear trend of footwall uplift and the pattern of stream incision into the footwall adjacent to the linear trend of footwall uplift reveal that fan dissection is a result of base level fall caused by ongoing tectonism along the El Paso fault system. The regional importance is discussed as the timing of faulting reveals relatively recent uplift …
Optimizing Uav Surveys For Coastal Morphodynamics: Estimation Of Spatial Uncertainty As A Function Of Flight Acquisition And Post-Processing Factors, Mark Lundine
Celebration of Learning
Recent developments in unmanned aerial vehicles (UAVs) and photogrammetry software enable the rapid collection of aerial photography and video over study areas of varying sizes, thereby providing ease of use and accessibility for studies of coastal geomorphology. However, there remains uncertainty over UAV survey techniques, with disagreement on specific flight patterns, flight altitudes, photograph amounts, ground control point (GCP) amounts, GCP spacing schemes, drone models, and which SfM software to use, amongst other study-specific parameters.
A controlled field test (of 1.2 hectares) was performed to determine SfM’s sensitivity to the following flight parameters: altitude (60 m, 80 m, 120 m), …
Spatial And Temporal Analysis Of Island Morphology In Lower Pool 18 Of The Mississippi River, Marissa C. Iverson
Spatial And Temporal Analysis Of Island Morphology In Lower Pool 18 Of The Mississippi River, Marissa C. Iverson
Celebration of Learning
The Upper Mississippi River System has a significant trend in island loss due to river engineering structures. However, Lower Pool 18 is observed as a counterexample to the island loss pattern with its island development near Lock and Dam 18 during the past 80 years. This research is modeled after a study done in Lower Pool 6 of the Upper Mississippi River where an island development was found to contradict the island loss prevalence. The Lower Pool 18 research’s goal is to map, describe, and explain spatial patterns of islands growth, persistence and loss. Historical maps and aerial photographs of …
Use Of Floodscape Mapping To Assess Changes In Inundation Frequency Of The Upper Mississippi River, Jeffrey L. Swanson
Use Of Floodscape Mapping To Assess Changes In Inundation Frequency Of The Upper Mississippi River, Jeffrey L. Swanson
Celebration of Learning
As an alternative to probability-based maps, DeJager (and others) reconceptualized floodplain mapping using the notion of “floodscapes” (DeJager et al., 2015). A floodscape map is developed using daily stage data and high-resolution topography to create maps that depict the average number of days of inundation (per year or growing season). Floodscape maps reveal intricate and continuous patterns of high-frequency flows that are critically important to floodplain ecological functioning. DeJager found significant correlations between floodscape inundation and riparian vegetation patterns but single floodscape maps only provide snapshots in time. This current research develops and utilizes multiple floodscape maps to quantify changes …
A Quantitative Analysis Of The Effects Of Urbanization, Mesophication And Prescribed Burns On Oak Woodlands In The Chicago Metropolitan Area, Chad Populorum
A Quantitative Analysis Of The Effects Of Urbanization, Mesophication And Prescribed Burns On Oak Woodlands In The Chicago Metropolitan Area, Chad Populorum
Celebration of Learning
Urban expansion has had devastating impacts on forest ecosystems, especially within the past century. Human attempts to dominate nature have diminished natural disturbance regimes, which have maintained the biodiversity and historic composition of these ecosystems. Fires have been a prominent force in maintaining the structure of oak, hickory and other heliophytic (sun loving and fire-adapted) forest systems. Human induced fire suppression has led to mesophication across North America. Mesophication is the transition from drier conditions with open canopies to wetter conditions with closed canopies. These new conditions decrease the survival rates of these important species and begin to favor mesophytic …
Results Of Test-Hole Drilling For Observation Well Planning In The Lower Loup Natural Resources District, Spring 2017, Douglas R. Hallum P.G., Sue Olafsen Lackey, Steven S. Sibray
Results Of Test-Hole Drilling For Observation Well Planning In The Lower Loup Natural Resources District, Spring 2017, Douglas R. Hallum P.G., Sue Olafsen Lackey, Steven S. Sibray
Conservation and Survey Division: Faculty and Staff Publications
The High Plains Aquifer underlies much of Nebraska. It is the primary source of groundwater within the Lower Loup Natural Resources District (LLNRD) of central Nebraska. Water derived from the aquifer is an important natural resource for the area and supplies water for recreation, wildlife and agriculture, as well as domestic, municipal, and industrial uses. Falling spring water levels measured in existing observation and irrigation wells have raised concerns about possible changes in water availability, groundwater-surface water relationships and water quality in the area, prompting the LLNRD to propose test holes and the collection of additional groundwater data in the …
Geochemical Dynamics And Nitrous Oxide Release From The Hyporheic Zone Of Streams, Annika Marie Quick
Geochemical Dynamics And Nitrous Oxide Release From The Hyporheic Zone Of Streams, Annika Marie Quick
Boise State University Theses and Dissertations
The hyporheic zones of streams and rivers, consisting of the sediments beneath and immediately adjacent to the stream channel, are an important site of geochemical processing. Due to the difficulty of measuring these geochemical processes in the hyporheic zone in situ with meaningful spatial and temporal resolution, we conducted multiple column and large-scale flume experiments to model 1D and 2D hyporheic flow paths and observed important geochemical reactions, including the production and consumption of nitrous oxide (N2O). N2O is a significant greenhouse gas, but the controls on its emissions from streams are poorly constrained. We describe …
Geostatistical Analysis Of Potential Sinkhole Risk: Examining Spatial And Temporal Climate Relationships In Tennessee And Florida, Kimberly Blazzard
Geostatistical Analysis Of Potential Sinkhole Risk: Examining Spatial And Temporal Climate Relationships In Tennessee And Florida, Kimberly Blazzard
Electronic Theses and Dissertations
Sinkholes are a significant hazard for the southeastern United States. Although differences in climate are known to affect karst environments differently, quantitative analyses correlating sinkhole formation with climate variables is lacking. A temporal linear regression for Florida sinkholes and two modeled regressions for Tennessee sinkholes were produced: a general linearized logistic regression and a MaxEnt derived species distribution model. Temporal results showed highly significant correlations with precipitation, teleconnection patterns, temperature, and CO2, while spatial results showed highly significant correlations with precipitation, wind speed, solar radiation, and maximum temperature. Regression results indicated that some sinkhole formation variability could be …
The Role Of Co2 Sublimation In Mass Wasting And Landscape Evolution Under Martian Conditions, Matthew Edwin Sylvest
The Role Of Co2 Sublimation In Mass Wasting And Landscape Evolution Under Martian Conditions, Matthew Edwin Sylvest
Graduate Theses and Dissertations
Here we present the first set of laboratory experiments under martian atmospheric conditions which demonstrate that the sublimation of CO2 ice from within the sediment body can trigger failure of unconsolidated, regolith slopes, and can measurably alter the landscape. Previous theoretical studies required CO2 slab ice for movements, but we find that only frost is required. Hence, sediment transport by CO2 sublimation could be more widely applicable (in space and time) on Mars than previously thought. This supports recent work suggesting CO2 sublimation could be responsible for recent modification in martian gullies.
A second set of experiments were carried out …
The Variability In The Morphological Active Width: Results From Physical Models Of Gravel‐Bed Braided Rivers, Sarah Peirce, Pauline Leduc, Peter Ashmore
The Variability In The Morphological Active Width: Results From Physical Models Of Gravel‐Bed Braided Rivers, Sarah Peirce, Pauline Leduc, Peter Ashmore
Geography & Environment Publications
The morphological active width, defined as the lateral extent of bed-material displacement over time, is a fundamental parameter in multi-threaded gravel-bed rivers, linking complex channel dynamics to bedload transport. Here, results are presented from 5 constant discharge experiments, and three event hydrographs, covering a range of flow strengths and channel configurations for which morphological change, bedload transport rates, and stream power were measured in a physical model. Changes in channel morphology were determined via differencing of photogrammetrically-derived digital elevation models (DEMs) of the model surface generated at regular intervals over the course of ~115 hours of experimental runs. Independent measures …
Assessing Land Deformation And Sea Encroachment In The Nile Delta, Egypt, Esayas Gebremichael
Assessing Land Deformation And Sea Encroachment In The Nile Delta, Egypt, Esayas Gebremichael
Research and Creative Activities Poster Day
Persistent scatterer interferometric analyses were conducted on a stack of 84 Envisat ASAR scenes spanning 7 years (2004 to 2010) over the entire Nile Delta of Egypt and surroundings to monitor the ongoing spatial and temporal land deformation, identify the factors controlling the deformation, and model the interplay between sea level rise and land subsidence to identify areas and populations threatened by sea encroachment by the end of the 21st century. Findings include: (1) general patterns of subsidence in the northern delta, near-steady (none) subsidence in the southern delta, separated by a previously mapped flexure zone undergoing uplift; (2) high …
Quantifying Knickpoint Behavior And Erosion Mechanisms In An Urbanized Watershed, Bull Mountain, Washington County, Oregon, Max Gregory Bordal
Quantifying Knickpoint Behavior And Erosion Mechanisms In An Urbanized Watershed, Bull Mountain, Washington County, Oregon, Max Gregory Bordal
Dissertations and Theses
Quantifying spatial and temporal patterns of rapid channelized erosion, on human time scales, is critical to understanding its processes and their consequences. This investigation utilized field observations, repeat terrestrial laser scanning (TLS), and Structure-from-Motion photogrammetry (SfM) to document the size and retreat rates of a knickpoint, defined as a localized near-vertical reach of a fluvial channel, and its contribution to erosion, in an urbanizing landscape with a loess substrate. The Bull Mountain area, in Washington County, southwest of Portland, Oregon, is an ideal study area, offering a measurable knickpoint that translates the response of the rapid erosion throughout this transient …
Using Repeat Terrestrial Laser Scanning And Photogrammetry To Monitor Reactivation Of The Silt Creek Landslide In The Western Cascade Mountains, Linn County, Oregon, Justin Craig Mccarley
Using Repeat Terrestrial Laser Scanning And Photogrammetry To Monitor Reactivation Of The Silt Creek Landslide In The Western Cascade Mountains, Linn County, Oregon, Justin Craig Mccarley
Dissertations and Theses
Landslides represent a serious hazard to people and property in the Pacific Northwest. Currently, the factors leading to sudden catastrophic failure vs. gradual slow creeping are not well understood. Utilizing high-resolution monitoring techniques at a sub-annual temporal scale can help researchers better understand the mechanics of mass wasting processes and possibly lead to better mitigation of their danger. This research used historical imagery analysis, precipitation data, aerial lidar analysis, Structure from Motion (SfM) photogrammetry, terrestrial laser scanning (TLS), and hydrologic measurements to monitor displacement of the Silt Creek Landslide in the western Cascade Mountain Range in Linn County, Oregon. This …
Reconstructing Late Holocene Paleofloods Along The Middle Tennessee River And Exploring Links With Climate And Land Use, Lance Stewart
Reconstructing Late Holocene Paleofloods Along The Middle Tennessee River And Exploring Links With Climate And Land Use, Lance Stewart
Scholars Week
Sediment stored in floodplains and low alluvial terraces along the middle Tennessee River reflects flood frequency and magnitude during the past ca. 2800 years. This study uses the stratigraphy, sedimentology, and geochronology of three alluvial terraces to infer past flooding and explore links with climate change and anthropogenic land-use practices. Four sites located on different geomorphic landforms adjacent to the Tennessee River preserve records of at least 11 major flood events from 2780 ± 185 BP to 100 ± 10 BP. Buried soils at three sites are older than ca. 1380 BP and suggest a relatively recent period of landscape …
The Effects Of Time And Topography On Deep Carbon Storage In The Clarks River Valley Of Western Kentucky, Benedict W. Ferguson
The Effects Of Time And Topography On Deep Carbon Storage In The Clarks River Valley Of Western Kentucky, Benedict W. Ferguson
Scholars Week
Soil organic carbon (SOC) dynamics at depths greater than one meter in valley bottoms are not well understood. This study examines the stock of SOC with depth across alluvial landforms in the Clarks River National Wildlife Refuge. Nine cores along three transects from terraces to floodplains and adjacent channel bars were collected to depths of 4 meters or refusal. Bulk density, clay content, and loss-on-ignition were used to estimate stocks. Age estimates based on radiocarbon suggest the landforms range in age from 7975 to 52 yr BP. Average SOC and carbon (C) flux varied with values of 1.76 kg/m2 …
Regional Stress Regime Study Of East Texas Based On Orientation Of Fractures In The Weches Formation, Cory D. Ellison
Regional Stress Regime Study Of East Texas Based On Orientation Of Fractures In The Weches Formation, Cory D. Ellison
Electronic Theses and Dissertations
Fractures in the Weches Formation in a roughly 50 mile radius around Nacogdoches, Texas were documented and analyzed using data obtained at various outcrops. This data was used to infer information about the regional stress regime based on the direction of maximum/minimum horizontal stresses (SHmax / SHmin) that formed the fractures. This is based on the principle that systematic, steeply dipping, mode I joints propagate in the direction of SHmax and normal to the direction of SHmin. Joints in the Weches Formation are typically iron filled and are predominantly opening mode, indicated by crack-seal formation, steep dip (700 – 900) …