Earth Sciences Commons^™

Molecular Interactions Of The Gas–Solid Interface: Svocs On Swelling Clays And San Joaquin Soil Surfaces, Liesl T. Jensen

Electronic Theses and Dissertations

Soil-derived mineral dust plays an important role in atmospheric chemistry by acting as a reactive interface for gas–particle interactions that influence the fate and transport of organic contaminants. Among soil components, clay minerals dominate surface reactivity due to their high surface area, structural complexity, and the presence of chemically active sites arising from cation exchange capacity and surface acidity. Environmental conditions, particularly relative humidity, further regulate these interactions by altering surface accessibility and competitive adsorption processes.

Despite the recognized importance of mineral dust, gas-phase interactions between organic compounds and clay minerals remain insufficiently understood, particularly under atmospherically relevant conditions. This …

A Large And Robust Legless Lizard (Squamata, Anguinae) From The Gray Fossil Site Of Eastern Tennessee, Justice D. Lamer

Electronic Theses and Dissertations

The early Pliocene Gray Fossil Site in Tennessee preserved an abundance of microfossils, including numerous anguid lizard specimens. This includes the following elements: dentaries, a pterygoid fragment, a jugal, frontals, parietal fragments, dorsal and caudal vertebrae, and many osteoderms. Because these specimens had not been placed taxonomically beyond the subfamily level, comparative anatomy of similar elements from extant anguids and some quantitative data were used to provide more refined identifications. Using these methods, it was determined that a new, robust type of Ophisaurus is represented at the Gray Fossil Site. Important novel features include relatively robust dentaries, fewer but broader …

Forest Cover Effects On Canopy Interception Loss, Evapotranspiration, And Soil Infiltration On Stormwater Detention Basins, Alexandria N. C. Perez

Electronic Theses and Dissertations

Developing cities and increased impervious surfaces has resulted in more surface runoff and severe flooding. Harris County, Texas has experienced major flooding events, such as Hurricane Harvey in 2017 which was estimated to be a 9,000-year flood event. The Harris County Flood Control District (HCFCD) is dedicated to creating, maintaining, and finding new ways to reduce flooding damage such as the use of detention basins as green infrastructure. These basins are either populated by grass or are planted with various tree species. This study will identify the planted trees’ canopy interception loss, reference evapotranspiration, and enhanced soil infiltration effects within …

Stratigraphic Analysis Of The Buda Limestone With Implications On Hydrocarbon Production Constraints, Madison And Houston County, Texas, Jeffrey C. Bridges

Electronic Theses and Dissertations

The Fort Trinidad and Alabama Ferry fields located in eastern Madison and southern Houston County, Texas, have produced approximately 100 million barrels of oil equivalent to date, with approximately 65% of this being oil. However, there has been considerable variation in production within this Cretaceous carbonate play of the Fort Trinidad field, despite similar well completions and perforated intervals. The Buda Limestone, a key producing formation in the Cretaceous interval, is described as under-pressurized and often has lost circulation problems during drilling due to sub-pressure vertical fractures. Within the producing interval, the mechanisms for water production versus oil production are …

Estimating Body Size And Biogeography In The Genus Alligator, Madelyn M. Turala

Electronic Theses and Dissertations

Several studies have examined correlations between total body length (TL) and skeletal measurements in the American alligator (Alligator mississippiensis), with some measurements serving as stronger predictors of TL than others. Femur length (FL) has been found to be tightly correlated with TL in A. mississippiensis, and this relationship has been used to estimate body size of extinct crocodilians. This thesis demonstrates that the humerus, radius, ulna, and tibia are also strongly correlated with TL and useful for body size estimation in A. mississippiensis, and thus, can be applied to related extinct crocodilians. Additionally, species distribution modeling …

On The Paleontology Of Belize, Alson Ovando

Electronic Theses and Dissertations

Paleontology can be considered an underrepresented and emerging area of science in Belize. A primary aim of this thesis is to provide a background of paleontology in Belize and present the first comprehensive study of Quaternary vertebrate fossils known from the country. Quaternary fossil sites across Belize include caves, rivers, and sinkholes. In addition to reviewing and assessing material from known sites, this thesis presents new information and discoveries that were made while investigating Belize’s Quaternary fossil record. This thesis also includes a geospatial model depicting ecoregions in Belize during the last glacial maximum. Overall, the results presented here demonstrate …

Ontogeny And The Effects Of Perinatal Stress In The First Immature Skeleton Of Teleoceras Aepysoma (Perissodactyla, Rhinocerotidae), Joe Gajewski

Electronic Theses and Dissertations

Recovery of an immature fossil rhinoceros (Teleoceras aepysoma) skeleton (ETMNH 32999) from the Gray Fossil Site in Tennessee offers the first insights into the ontogeny of the species. ETMNH 32999 is interpreted to be a subadult male in an age class equivalent to ~17-20% of potential lifespan. Comparative analyses support the hypothesis that subadults of related taxa are typically ~91% of average adult size in most dimensions. However, certain cranial dimensions are substantially lower than expected in ETMNH 32999, averaging only ~74% of the average conspecific adult. Such departure from typical growth rates is suggested to be attributable …

Machine-Learning Landslide Susceptibility And Runout Modeling In The Nolichucky River Gorge After Hurricane Helene, Grace Braver

Electronic Theses and Dissertations

Extreme rainfall from Hurricane Helene (September 2024) triggered widespread landslides across the southern Appalachian region, highlighting the need for rapid landslide susceptibility assessments that capture both landslide initiation and downstream runout. Traditional susceptibility models often focus solely on initiation zones, limiting their ability to identify which slopes will generate destructive landslides or where material will travel. This study addresses that gap by (1) integrating Geographic Information System (GIS)-based machine learning susceptibility modeling using ArcGIS Pro: Maximum Entropy (MaxEnt) and Random Forest-Based and Boosted Classification and Regression (FBBC) and (2) the U.S. Geological Survey (USGS) Grfin (Growth, Flow, and Inundation) runout …

Integrated Geophysical, Geotechnical, And Mineralogical Characterization Of Expansive Weches Formation Soils In East Texas: Implications For Infrastructure Design, Samuel Annobil

Electronic Theses and Dissertations

This study investigates the geotechnical, geophysical, and mineralogical characteristics of soils derived from the Weches Formation in Nacogdoches County, East Texas, with emphasis on the relationships among electrical resistivity, moisture condition, compaction state, and mineralogical composition. The Weches Formation is well known for producing clay-rich, moisture-sensitive soils that pose challenges to subgrade performance because of their plasticity and swelling behavior. Representative soil samples were collected and subjected to laboratory testing, including particle size analysis, Atterberg limits, Standard Proctor compaction, free swell tests, electrical resistivity measurements, and X-ray diffraction (XRD) mineralogical analysis. The soils are predominantly fine-grained and clay-rich, with USCS …

Impacts Of Management Practices And Soil Properties On Free-Living Nitrogen Fixation In Eastern South Dakota, Laura Galvan Nuevo

Electronic Theses and Dissertations

Free-living nitrogen (N) fixation (FLNF) may represent a sustainable pathway to supplement crop N demand in agroecosystems, yet edaphic and management factors regulating this process under field conditions remain poorly understood in the Northern Great Plains. Using 15N2 direct method to quantify potential FLNF (pFLNF) and baseline FLNF (bFLNF), this thesis investigates how crop rotations (2-, 3-, and 4-year systems), tillage management (conventional vs. no-till), cover cropping, and soil properties affect the potential of free-living diazotrophs to supply N via FLNF in a long-term no-till corn-based system in Southeastern South Dakota. A two-year field study evaluated pFLNF across four growing …

A Sedimentary Source Of Rare Earth Elements In The North Atlantic, Rylee D. Lindner

Electronic Theses and Dissertations

Individually and as a series, the Rare Earth Elements (REEs) are powerful geochemical tracers of environmental processes. However, ambiguities in the oceanic budgets of the REEs hamper their application. Growing evidence suggests a sedimentary benthic flux via the pore water is the major source of REEs to the ocean, with extrapolated estimates of this flux being equivalent in magnitude to that “missing” from modern budgets. However, existing pore water REE data are available from only a few locations globally with no representative dataset from the open North Atlantic. This data scarcity limits our ability to constrain flux estimates and understand …

Direct And Satellite-Based Quantification Of Greenhouse Gas Fluxes In Small Ponds., Mark Christopher Tierney

Electronic Theses and Dissertations

As evidenced by their historic losses due to anthropogenic activities, wetlands are undervalued ecosystems that provide numerous ecosystem services, from recreational opportunities to carbon (C) storage. However, these wetlands are also the largest natural source of atmospheric methane (CH₄). Additionally, small water bodies (< 10,000 m²) are disproportionately large emitters relative to larger lakes and reservoirs. As construction and restoration efforts proceed, it is crucial to identify wetlands that need restoration and to understand the factors driving both greenhouse gas (GHG) fluxes and the C balance of these systems. This dissertation investigates the drivers of greenhouse gas fluxes …

Floodplain Lake Hydrodynamic And Morphodynamic Connections Through Hydraulic Modeling Along The Pee Dee River, Sc, Charles Cj Mina

Electronic Theses and Dissertations

Rivers have been essential in the success of humankind. This reliance has created a vested interest in studying the rivers' environmental history through using floodplain deposits, with the assumption that coarser sediments correlate to higher discharge floods. However, shifting hydrological connectivity and hydrodynamics can complicate this correlation in primary repositories of flood deposits, oxbow lakes, by altering the texture of sediments delivered to them. Studying these complications is essential for quantifying paleoflood magnitude using the sediment record, but has been difficult, as the currently used index of hydrological connectivity relies on water stage, which does not reflect the sediment flux …

Geochemical Analysis Of The Eagle Ford Shale In Webb And Dimmit Counties, Tx, Natalie G. Girlinghouse

Electronic Theses and Dissertations

The Late Cretaceous Eagle Ford Shale of South Texas is a mixed carbonate–siliciclastic succession that serves as both a prolific hydrocarbon source and reservoir. This study integrates chemostratigraphy, mineralogical analysis, and elemental ratio proxies to reconstruct depositional environments and assess controls on detrital influx, paleoproductivity, and redox conditions across multiple cores in Webb and Dimmit counties. Major, trace, and redox-sensitive elements were evaluated alongside Total Organic Content (TOC) and carbonate content to identify stratigraphic trends and environmental shifts.

Results reveal distinct geochemical signatures between the Upper and Lower Eagle Ford Shale, with the Lower Eagle Ford characterized by elevated Al-rich …

Structural Geology Of The Brady Mountain Area, Ouachita Mountains, Arkansas: Integrating Field Mapping, Geospatial Techniques, Photogrammetry And 3d Modeling For Structural Analysis, Emmanuel Darko, Zachariah Fleming

Electronic Theses and Dissertations

Much of the Ouachita orogenic belt, representing the deformed Paleozoic rocks flanking the southern margin of the North American craton, is buried beneath post-orogenic Mesozoic and Tertiary sediments composing the Gulf Coastal Plain. The Ouachita Mountains of Arkansas and Oklahoma are the largest areas of outcrop for the Pennsylvanian-age Ouachita orogenic belt, making it an ideal place to study the orogeny. This study focuses on the Brady Mountain area within the Benton Uplift, the orogenic core of the Ouachita Mountains in western Arkansas. The region is comprised of numerous ridges trending nearly east-west and are for the most part densely …

Reservoir Characterization Of The Clarksville Formation In Red River County, Texas, Matthew Allen Parker

Electronic Theses and Dissertations

The Upper Jurassic Clarksville Formation in northern Texas and southern Oklahoma is a productive but poorly understood sandstone–conglomerate unit with unresolved questions regarding its depositional environment and sediment provenance. This study evaluates the depositional setting, spatial distribution, and diagenetic controls of the Clarksville Formation using integrated core and well log analyses in Red River County, Texas. Three cores (Lennox Unit #1, Reeder Oil Unit #2, and Reeder Oil Unit #7) were analyzed for lithology, mineralogy, porosity, permeability, and fluid saturation, and correlated with 137 well logs to map formation thickness and regional trends.

Four lithofacies were identified based on core …

Comparison Of Nutrient Concentrations And Primary Production Indicators Across Plume Fronts, Taylor Dishon

Electronic Theses and Dissertations

Coastal buoyant plumes carry low-salinity waters containing particulate and dissolved terrestrial materials with an abundance of nutrients into the coastal ocean, including inorganic nitrogen and phosphorous. Plume fronts act as transport barriers created from the convergence of a fresher plume with an older, saltier plume or with ambient waters, leading to potential accumulation of phytoplankton and nutrients. This accumulation creates an optimal environment for primary production. The primary goals of this study were: to investigate the distribution of and potential relationships between nutrient concentrations and chlorophyll a across plume fronts of the Winyah Bay River Plume, and examine potential relationships …

Diagenesis And Controls On Porosity And Permeability In The Upper San Andres Formation Of West Texas, Jack Butcher

Electronic Theses and Dissertations

West Texas reservoirs on the Central Basin Platform (CBP) are dominated by Permian-age carbonate deposits, significantly contributing to petroleum production. The Upper Permian-aged San Andres Formation, composed primarily of dolomite and limestone, is a prolific reservoir. This study assesses diagenetic influences on porosity and permeability within the San Andres Formation along the northern CBP. Two cores from the Monument 4-2 and Peterson 1 wells in West Texas were analyzed using core descriptions, thin section petrography, XRD, XRF, and MICP. Results indicate that dolomitization enhances porosity, with intercrystalline and moldic porosity being dominant, while late-stage cementation and compaction reduce permeability. XRD …

Inferring Feeding Biology In Extinct Shrews (Soricidae: Mammalia): Application Of A Linear Morphometric Approach, Derek J. Den Ouden

Electronic Theses and Dissertations

Linear morphometrics have been used extensively to infer the ecology of fossil organisms, but shrews have not yet been thoroughly explored using this technique. Often considered to have a homogenous insectivorous diet, direct dietary observation suggests shrew dietary diversity is substantial. Diversity of this nature is well established to have influenced skull morphology in other mammal clades, so similar patterns are hypothesized to be detectable in shrews. To test this, I examined the link between known diet and morphological disparity in extant shrews using linear morphometrics and then utilized that framework to infer the dietary ecology of several fossil taxa. …

Cranial Ontogeny Of The Extinct Dwarf Tapir Tapirus Polkensis; With Comparison To That Of The Extant Tapirus Bairdii (Tapiridae, Perissodactyla), Johannah Orendorff

Electronic Theses and Dissertations

Tapirus polkensis is the smallest known species of tapir to ever live, and the largest deposit of their fossils is currently located at the GFS in Gray, TN. Phylogenetics suggest that the extant T. bairdii may be the sister taxon to T. polkensis, although they differ greatly in their morphology. Variation exists among adult T. polkensis specimens, with patterns not present in T. bairdii. For this study, as series of 2D GMAs, with TPSs, were rendered on 10 skulls of T. polkensis and 48 skulls of T. bairdii, across both species’ ontogenetic series. Analyses confirmed that growth …

Characterization Of Residual Mineral Content Of Bauxite Stockpiles In Saline County, Arkansas: An Xrd Analysis Approach, Andrew Kaze Sezibera

Electronic Theses and Dissertations

The Saline Mining District of central Arkansas once led U.S. alumina production and hosts extensive bauxite and nepheline syenite deposits. With the depletion of highgrade ore, renewed interest in bauxite stockpiles has focused on critical mineral potential. Previous X-ray Fluorescence studies have identified critical elements in significant concentrations, including uranium (U), thorium (Th), gallium (Ga), molybdenum (Mo), and lanthanides (Ln). This study examines five stockpiles (SP1, Clay, SP2, SP3, and SP4) in Section 20 of the Aluminum Company of America (ALCOA) Saline County bauxite mine, using Xray Diffraction (XRD) on 25 samples to characterize mineral phases and compare them with …

Lidar-Based Delineation Of Karst Features In The Gypsum Plain, Eddy County, New Mexico And Culberson County, Texas, Kaitlyn Rae Levassar

Electronic Theses and Dissertations

The Gypsum Plain of the Delaware Basin encompasses approximately 1,800 km² of massive to laminated gypsum (anhydrite in the subsurface) outcrop of early Ochoan Castile and Salado strata. These extensive Permian-age evaporites host significant karst phenomena as a result of the region's complex hydrogeologic system which has continuously evolved since the early Paleogene. Karst features that manifest surficially as sinkholes when breached range from extensive hypogene cave systems to epigene features and suffosion caves. In contrast, paleo-collapse structures forming breccia pipes attesting to more ancient karst within these strata often manifest as topographic highs across the Gypsum Plain.

Until …

Identifying Salt Suture Zones And Lithological Changes Of The Louann Salt In The Gulf Of Mexico Basin, La. U.S.A., Jamie Dale Singer

Electronic Theses and Dissertations

The Louann Salt, a key evaporite unit in the Gulf of Mexico Basin, influences salt tectonics, hydrocarbon migration, and basin evolution. This study examines Louann Salt deposition and deformation within the Puma Diapir, focusing on mineralogical, geochemical, and structural features of suture zones in three offshore wells (Puma 2(w), Puma 3, and Panther). Using drill cuttings, X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), well-log data, and 3D seismic interpretation, the study analyzed salt composition and suture formation. Results show the salt primarily consists of halite, with minor anhydrite, gypsum, and sylvite, indicating continuous precipitation. Geochemical …

Revealing Hidden Histories: A Multi-Sensor Aerial Survey For Detecting Unmarked Burials At Sinking Spring Cemetery, Abingdon, Va, Noah Hall

Electronic Theses and Dissertations

The Sinking Spring Cemetery, established in 1773 in Abingdon, Virginia, spans 11 acres and is divided by a road. The 9-acre southern section was reserved for white church members. Enslaved individuals and free people of color were buried in the smaller northern section, where few headstones remain today. This study aimed to map the unmarked graves using thermal, multispectral, and Light Detection and Ranging (LiDAR) sensors deployed on unmanned aerial systems. Graves were characterized by subtle topographic depressions mapped by LiDAR and cooler radiant temperature anomalies in thermal imagery. Thermal data collected at different times of the day and year …

Quantifying Landscape Variability Of Dynamic Soil Properties In The James River Valley, Eastern South Dakota, Sage Reuter-Schmitt

Electronic Theses and Dissertations

Dynamic soil properties (DSP) are a great tool for monitoring land-use change, and they are frequently used as soil health metrics. The NRCS and other soil researchers often use repeating, single-point or nested-point DSP studies to monitor and better understand the effects of land management decisions. While these studies capture the temporal variability of DSPs, they overlook the field-scale spatial variability of DSPs. Soil organic carbon (SOC) provides critical services to the ecosystem and other environments. These traits, as well as its susceptibility to management decisions, make SOC an important soil health indicator and DSP. Measuring SOC is often time …

The Spatial And Temporal Dimensions Of Plant–Soil Feedback In Native Perennial Monocultures, Bret Lang

Electronic Theses and Dissertations

Plant-soil feedbacks (PSFs) describe how plants change their soil environment in ways that can either negatively or positively affect subsequent plant growth. In doing so, they offer an opportunity to connect ecological processes with agricultural practice. My dissertation examines PSFs created by native perennial monocultures, commonly used for native seed production, across time and space, and through soil legacies. Specifically, I focus on how plant species identity shapes both soil nutrient and soil microbial community responses. To address these questions, I conducted field experiments with monocultures of five forb species native to South Dakota and established plots with these species …

Multi-Source Remote Sensing–Based Soil Moisture Prediction Using Machine Learning, Niraj Neupane

Electronic Theses and Dissertations

Soil moisture (SM) plays a central role in climatic and environmental processes, influencing shear strength of soil, agricultural productivity, land–atmosphere interactions, and hydrologic functioning. However, accurately estimating SM across diverse climatic regions remains challenging due to spatial heterogeneity, limited in situ measurements, and inconsistencies in sensor resolution. Machine learning (ML) and remote sensing offer promising avenues for improving SM prediction, yet many existing approaches struggle with generalization across climatic gradients and often fail to capture temporal variability. This study integrates multi-source satellite and climate datasets, including SMAP L4_SM, MODIS land surface temperature, Daymet meteorological variables, and in situ observations from …

Enhancing Alfalfa Persistence In Rangelands: Evaluating Morphological Traits Of Medicago Sativa Subsp. Falcata Germplasm, Abdulallah Mohammed Alomair

Electronic Theses and Dissertations

Rangelands cover nearly half of the Earth’s surface, representing about 54% (79 million km2), and occur in different types and climates worldwide. Alfalfa (Medicago sativa L.) is a major component in rangelands and covers about (320 thousand km2), representing about 0.4% of total global rangeland area. As a critical perennial legume crop, alfalfa can improve soil health by fixing approximately 336 kg/ha/year of nitrogen and sequestering up to 614 kg/ha/year of carbon, while enhancing livestock production due to its high content level of vitamins, magnesium, minerals, fiber, and protein. However, environmental stresses such as drought, freezing, and grazing limit alfalfa …

Evaluation Of Strip-Tillage And Banded Phosphorus And Potassium Fertilizer For Corn Production In Eastern South Dakota, Charles N. Tesch

Electronic Theses and Dissertations

In South Dakota, the adoption of no-till and other conservation tillage practices has grown in recent years. However, conventional tillage is still a common practice in the eastern third of the state, negatively affecting soil health and the environment. Strip-tillage has gained interest in this region as a way to transition to conservation tillage while retaining some benefits of conventional tillage. Strip-tillage also provides the ability to subsurface band nutrients, particularly phosphorus (P) and potassium (K) fertilizers within the tillage strip, potentially improving nutrient accessibility and recovery while reducing environmental risks. This study aimed to investigate (i) the effects of …

Evaluating The Usefulness Of Geochronometers In The Packsaddle Domain For Refining The Timing Of Metamorphism Via High-Resolution Petrography, Enchanted Rock State Natural Area, Llano Uplift, Texas, Haylee Vike

Electronic Theses and Dissertations

The Llano uplift, central Texas, exhumes Mesoproterozoic rocks with a complex history of metamorphism, deformation, and magmatism. There are three recognized metamorphic events related to the Grenville orogeny (~1.3-0.9 Ga). The timing of these metamorphic events is not well resolved due to past methods, technology, and lack of published geologic context for many of the current dates. These current time constraints on metamorphic timing could be further refined through modern geochronologic and petrochronologic methods.

A majority of U-Pb zircon dates from the Valley Spring (~1366-1232 Ma), Coal Creek (~1326-1275 Ma), and Packsaddle (~1257-1215 Ma) domains are interpreted as crystallization ages …