Interactive Effects Of Cover Crops, Invertebrate Communities And Soil Health In Corn Production Systems, Claire Lacanne

Electronic Theses and Dissertations

The adoption of regenerative farming practices is gaining traction, but the costs and benefits are not often considered on a systems level. Encouraging biodiversity and soil health is the goal of many agricultural practices used in regenerative farming; regenerative systems employ practices which abide by the two main principles of increasing biodiversity and decreasing disturbance, with the goal of encouraging ecosystem functioning to minimize inputs and maximize the productivity of a farm. I examined the management of corn (Zea mays) fields across four states in the Upper Midwest region of the United States. Regenerative systems in this study …

Co2 Adsorption On Volcanic Ash: Net Contribution Of Volcanic Eruptions To The Global Carbon Cycle, Lee New

Electronic Theses and Dissertations

Adsorption of co2 on mineral surfaces accounts for a small percentage of the terrestrial co2 sink. Volcanic ash is virtually free of co2 when erupted and has a high surface area resulting in a high capacity for co2 adsorption. Volcanism is commonly assumed to be only a source of co2, but pyroclastic eruptions can also potentially serve as a sink. Adsorption was investigated for 6 volcanic ash samples of andesitic composition from four volcanoes: Okmok, Redoubt, Spurr, and Tungurahua. The eruption of volcano redoubt released 0.75 x 109 metric tons of co2 and 55 x 109 kg of ash throughout …

Detection Of Sedimentary Depositional Cycles In The Salado Formation, Southeastern New Mexico, Scott Paul Milo

Electronic Theses and Dissertations

An abundance of evaporitic features is preserved throughout the approximately 2,000-foot-thick Salado formation that is present across west Texas and southeastern New Mexico. The formation and preservation of evaporitic features are largely influenced by hydrology, and so those found in the Salado represent an uninterrupted record of hydrogeologic conditions in what is now the southwestern United States during the late Permian. Because it is home to the Waste Isolation Pilot Plant (WIPP) repository chamber, the salado has been the subject of countless studies ranging from areas of sedimentology, to geochemistry, to geotechnical engineering, to hydrology. However, until now there have …

Carbon Cycle Trends Recorded By Organic Carbon Stable Isotopes In Paleocene Strata, Benton County, Mississippi: Implications For Chronostratigraphy Of The Porters Creek And Naheola Formations, Erica Gerweck

Electronic Theses and Dissertations

The paleocene-eocene thermal maximum (petm) is one of the most studied carbon isotope excursions in earth's history. The petm occurred 55 million years ago when excess isotopically heavy carbon (c13) was added into earth's carbon cycle, resulting in ecological and environmental changes. The petm is marked by a negative stable carbon isotope excursion (cie) in marine and continental strata around the globe. The paleocene and eocene boundary is contained in the sedimentary fill of the Mississippi embayment so there is high potential to produce new petm stable isotope datasets. The purpose of this project is to analyze the boundary for …

Characterizing Coastal Marsh Groundwater Hydrology With Multichannel Electrical Resistivity Tomography, Matthew R. Kestner

Electronic Theses and Dissertations

Subsurface waters are highly enriched in nutrients compared to surface waters in the coastal salt marsh environment and may, therefore, have a large effect on biogeochemical processes. There have been numerous studies examining marsh platform hydrology, however, there is a lack of information on the hyporheic zone within tidal creeks in coastal salt marsh environments. Hyporheic exchange has been studied in various non-tidal freshwater systems and verified as a significant pathway for solute transport in typical stream settings. The total volume of water cycled through salt marsh tidal creek hyporheic zones could prove to be a significant component of the …

Paleodrainage Insights Into The Fluvial And Glacial History Of The Western Chukchi Margin, Arctic Alaska, Brittany A. Stockmaster

Electronic Theses and Dissertations

Chirp subbottom data collected from the Chukchi shelf, offshore of northwest Alaska, revealed extensive paleodrainage networks that incised the margin during sea level lowstands. These features are cut into folded Cretaceous bedrock strata and represent multiple sea level cycles. Several large incised valleys, 10s of km wide and up to 54 m deep, as well as numerous smaller, individual channels were identified. Sources of fluvial input include several, smaller rivers on the northwest Alaskan coast, such as the Kokolik, Kuk, Kukpowruk, and the Utukok Rivers. Correlation of sediment infill patterns provided insight to paleochannels and paleovalleys as well as outlined …

Rock Glacier Hydrology In The San Juan Mountains, Colorado, Emilio Ian Mateo

Electronic Theses and Dissertations

Rock glaciers are unique geomorphological features located in alpine environments and are found in the San Juan Mountains of Colorado. There has been little research done on rock glaciers compared to their ice glacier counterparts. Most rock glaciers are located on the northern slope aspect in mountainous areas (Janke 2007), however, there are multiple in southwest Colorado with different aspects. This research project asks how slope aspect influences the hydrological processes of streams sourced from rock glaciers in the San Juan Mountains. This project focused on three basins that are adjacent to each other and share a common peak, Gilpin …

Geologic And Geochemical Characterization Of Cross-Communication Potential Within The Northern Edwards Aquifer System, Texas, Ingrid J. Eckhoff

Electronic Theses and Dissertations

The Edwards Aquifer is a large, complex groundwater system located throughout Central Texas in association with the Balcones Fault Zone. The San Antonio and Barton Spring segments of the Edwards Aquifer have been extensively studied in the past because they provide groundwater resources to the largely urbanized areas of San Antonio and Austin, respectively, and smaller communities along the Interstate 35 corridor. Previous research has been conducted on these southern and central portions of the Edwards Aquifer system, which have characterized the structural, hydrogeological and geochemical variations within the highly karsted region. However, the Northern Segment of the Edwards Aquifer …

Speleogenesis And Delineation Of Megaporosity And Karst Geohazards Through Geologic Cave Mapping And Lidar Analyses Associated With Infrastructure In Culberson County, Texas, Jon T. Ehrhart

Electronic Theses and Dissertations

The Gypsum Plain region of the Delaware Basin hosts approximately 1800 km² of the Castile Formation outcrop. A myriad of karstic developments from closed sinkholes to large multi-kilometer cave systems have been documented within the region. Karst studies on the distribution and speleogenetic evolution within Castile strata began within the last decade with ever increasing data resolution. In this study, a combination of both physical field surveys and analyses of high resolution (~30 cm accuracy) LiDAR data was used to create a theoretical model for karst development across the region. This idealized model considers speleogenetic formation type variations (hypogene …

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …

Geotechnical Properties Of The Travis Peak (Hosston) Formation In East Texas: A Compressive And Tensile Strength Analysis Using Regression Analysis., Pawan Kakarla

Electronic Theses and Dissertations

The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Geotechnical engineering is the branch of civil engineering which works on the principles of soil and rock mechanics to evaluate subsurface conditions, stability of slopes, foundations of structures and construction of earthworks. The main focus of this study was to calculate the strength of Lower Cretaceous Travis Peak Formation rocks of East Texas and to check the accuracy by comparing it with Regression analysis. The parameters which were used were the Uniaxial Compression …

Cone In Cone Concretions Of The Stanley Group In Southeastern Oklahoma, Kyle B. Ayres

Electronic Theses and Dissertations

Cone in cone concretions found in the Stanley Group of Southeastern Oklahoma have a variety of external and internal attributes which allow diagenetic and theoretical models of formation to be hypothesized. Stanley Group carbonate cone in cone concretions are initially formed in sulfur reducing horizons at shallow burial depths in a poorly circulated possibly deep trough containing siliceous sediments and organic matter. Collected concretions near the town of Smithville, Oklahoma displayed four different external morphologies and four variations of mineral constituents. All concretions contained microscopic cones which initiated diffusion and/or fluid patterns and is an early cementation process that directly …

An Investigation Of Hydrogeologic, Stratigraphic, And Structural Controls On Acer Grandidentatum Communities In A Karst Landscape, Owl Mountain Province, Fort Hood Military Installation, Texas, Melinda S. Faulkner

Electronic Theses and Dissertations

The Owl Mountain Province is located within the Fort Hood Military Installation, an approximately 880 km2 installation established in the 1940s in Bell and Coryell counties, Texas, which has undergone extensive land use changes associated with military training, maintaining much of the vegetation in early succession. This study investigates thelithologic, stratigraphic, and structural controls on the hydrologic, hydrogeologic, and geomorphologic evolution of the Owl Mountain Province as expressed by mesic vegetation communities, including Pleistocene relicts Acer grandidentatum, within karst terrains. These systems exhibit complexly overprinted speleogenetic evolutions within a dynamic groundwater regime resulting from regional climate shifts throughout the …

Characterization Of Lower Permian Carbonate Subaqueous Gravity Flows In Crockett County, Texas, Wesley L. Turner

Electronic Theses and Dissertations

Transitional sediments on carbonate ramp slopes act as a link to relatively well-studied platform and basin depositional environments. In the southern Midland Basin, the key to understanding the relationship between these environments lies in the allochthonous gravity flow sediments found on the slope. Here, a succession of various gravity flow deposits is used to interpret how base level fluctuations affect the type of deposits found on the slope and their effect on the deep basinal environment. This study utilizes core samples from the Wolfcamp Formation adjacent to the Central Basin Platform in five wells in Northwest Crockett County, Texas. The …

Speleogenesis Of Critchfield Bat Caves And Associated Hydrogeology Of The Northern Edwards Aquifer, Williamson County, Texas, Ashley N. Landers

Electronic Theses and Dissertations

Karst development in the Edwards Aquifer has been significantly studied in the San Antonio and Barton Spring Segments; however, karst development remains poorly studied in the Northern Segment. Detailed characterization of the Northern Segment is vital for future water conservation because of increasing urban sprawl along the Interstate 35 corridor. The Northern Segment of the Edwards Aquifer consists of Lower Cretaceous strata of the Comanche Peak, Edwards, and Georgetown formations. The stratigraphy is dominated by Edwards Limestone as it is the only formation that crops out in the study area.

Karst, stratigraphic, GIS, and geochemical studies were conducted to evaluate …

The Stratigraphic Position Of Fossil Vertebrates From The Pojoaque Member Of The Tesuque Formation (Middle Miocene, Late Barstovian) Near Española, New Mexico, Garrett R. Williamson

Electronic Theses and Dissertations

The stratigraphy of the Pojoaque Member of the Tesuque Formation near Española, NM is not well understood. This region, during the Middle Miocene, represented a dynamic alluvial fan-fluvial-lacustrine environment within the Española Basin while the Rio Grande Rift was active. Cavazza (1986) identified two paleodrainage systems (lithosome A, basin-margin facies and B, basin-floor facies) by means of sandstone and conglomerate petrology, paleocurrent, and sedimentary facies analyses. After x-ray diffraction analyses of claystones within lithosome B, mordenite was discovered, which is a zeolite mineral commonly found within volcanic rocks. This is significant because the presence of mordenite confirms Cavazza’s (1986) conclusion …

Analyzing The Phenologic Dynamics Of Kudzu (Pueraria Montana) Infestations Using Remote Sensing And The Normalized Difference Vegetation Index., Faye Peters

Electronic Theses and Dissertations

Non-native invasive species are one of the major threats to worldwide ecosystems. Kudzu (Pueraria montana) is a fast-growing vine native to Asia that has invaded regions in the United States making management of this species an important issue. Estimated normalized difference vegetation index (NDVI) values for the years 2000 to 2015 were calculated using data collected by Landsat and MODIS platforms for three infestation sites in Kentucky. The STARFM image-fusing algorithm was used to combine Landsat- and MODIS-derived NDVI into time series with a 30 m spatial resolution and 16 day temporal resolution. The fused time series was …

Investigating The Influences Of Climate On The High Elevation Snowpack Hydrology In The Upper Colorado Region., Claire-Louise Bode

Electronic Theses and Dissertations

A change in climate in the western United States has already affected and will continue to affect the onset of snow melt in many parts of the country. The effect of climate change on snow water equivalent, snowmelt runoff and total streamflow with respect to their elevation distribution is examined across the Colorado Headwaters Basin. This is a high altitude location within the Upper Colorado Basin region. The total streamflow of this region has a significant contribution from the spring season snow melt. An increase in air temperature in the Colorado Headwaters Basin over a few years will change the …

Peccaries (Artiodactyla: Tayassuidae) From The Late Miocene To Early Pliocene Gray Fossil Site: Regional Implications With A Review Of Tayassuinae, Evan M. Doughty

Electronic Theses and Dissertations

Analysis of the Gray Fossil Site peccary material indicates the presence of up to three species. Comparisons with the tayassuid material known from the Tyner Farm and Bone Valley Formation of Florida allows the identification of Mylohyus elmorei and at the GFS. Within the GFS material, Prosthennops cf. P. serus and cf. Catagonus sp. are also tentatively recognized but further verification is required. The known range for Prosthennops is expanded into the Appalachian region. Presence of M. elmorei at the Gray Fossil Site provides the first known occurrence of this species outside of the Palmetto fauna of Florida, indicating that …

Description, Taphonomy, And Paleoecology Of The Late Pleistocene Peccaries (Artiodactyla: Tayassuidae) From Bat Cave, Pulaski County, Missouri, Aaron L. Woodruff

Electronic Theses and Dissertations

The late Pleistocene faunal assemblage from Bat Cave, central Ozarks, Missouri provides an opportunity to assess specific aspects of behavior, ecology, and ontogeny of the extinct peccary Platygonus compressus. All identifiable elements referable to this taxon were catalogued and examined, and a minimum number of individuals of 70 was determined for the sample. The presence of distinct, non-overlapping age groups suggests that P. compressus utilized Bat Cave on a seasonal basis. A predator-prey relationship with Canis dirus, the second most abundant vertebrate from the Bat Cave site, is also described in this study. Damage patterns suggest that the …

New Records Of Colubrids From The Late Hemphillian Gray Fossil Site Of Northeastern Tennessee, Derek J. Jurestovsky

Electronic Theses and Dissertations

The Gray Fossil Site is a rich Hemphillian (North American Land Mammal Age) locality located in northeastern Tennessee which has produced tens-of-thousands of fossils of multiple taxa including hundreds of individual snake skeletal remains. Analyzed here are cranial and vertebral fossils identified as belonging to various colubrid taxa including Carphophis sp., Gyalopion sp., Heterodon sp., Natricinae indeterminate, Thamnophis sp., and a new, undescribed genus and species. In addition, multiple new features of snake vertebrae are described, some of which question the validity of the genus Neonatrix. Finally, the distribution and paleoecology of the listed genera allows an interpretation of …

Description Of Cranial Elements And Ontogenetic Change Within Tropidolaemus Wagleri (Serpentes: Crotalinae)., Nicolette L. Hill

Electronic Theses and Dissertations

Tropidolaemus wagleri is a species of Asian pitviper with a geographic range including Thailand, Vietnam, Malaysia, Singapore, Bruniei, parts of Indonesia, and the hilippines. Tropidolaemus is a member of the Crotalinae subfamily, within Viperidae. The genus Tropidolaemus includes five species, and was once included within the genus Trimeresurus. While some osteologic characteristics have been noted a comprehensive description of cranial elements has not been produced for T. wagleri. An in-depth description of the cranial skeleton of Tropidolaemus wagleri lays the foundation for future projects to compare and contrast other taxa within Crotalinae and Viperidae. The chosen reference specimen …

Ecological Niche Modeling Of The North American Giant Salamander: Predicting Current And Future Potential Distributions And Examining Environmental Influences, Selena S. Roark

Electronic Theses and Dissertations

North American Giant Salamanders (Cryptobranchus alleganiensis), commonly known as hellbenders, have been experiencing a population decline for decades due to human influences, such as pollution and habitat destruction. Many efforts are underway to save the hellbender but their entire potential geographical range has not been well-studied. Currently, hellbender populations are delineated by county boundaries and are on the International Union for Conservation of Nature Red List. The Genetic Algorithm for Rule-set Production, an Ecological Niche Model, was used to model the current hellbender potential distribution at a macro-scale under two different environmental scenarios. Additionally, future potential distributions were …

Evaluation Of Groundwater Quality In Paleozoic Aquifers Using Gis Techniques, Central Texas, Garrett R. Harris

Electronic Theses and Dissertations

Lab analyses of groundwater chemistry from monitoring wells completed in the Paleozoic Aquifers surrounding the Llano Uplift of Central Texas has been recorded and made available to the public through the Texas Water Development Board (TWDB). This study evaluated the results of these data dating back to the 1940s to determine changes over time, the dynamics of the hydrologic system, and the locations where hydraulic connectivity is most probable. The initial results established two distinct hydrologic systems that required the separation of the northern from the southern region. The northern sub-region (NSR) contains the largest expanse of continuity of both …

Source Apportionment Of Atmospheric Particulate Matter In Developing Countries Using Trace Elements And Stable Metal Isotope Ratios, Nitika Dewan

Electronic Theses and Dissertations

The work presented herein details the source apportionment of atmospheric particulate matter in developing countries (Kyrgyzstan in Central Asia, metropolitan cities in Northern India, and Shenzhen in China) using trace elements and stable metal isotope ratios. The first study focused on the development of a novel method for the concomitant separation of rare-earth elements in environmental samples of any geological origin. The separation procedure is based on three extraction chromatographic materials, referred to as Sr.Spec, TRU.Spec, and Ln.Spec. This triple column arrangement enables the simultaneous isolation of pure Sr and Nd fractions in less than one day and with great …

The Porosity And Permeability Distribution Of The Shoal Grainstone And Thrombolitic Facies Of The Smackover Formation In Little Cedar Creek And Brooklyn Fields In Southwestern Alabama, Devin Thomas

Electronic Theses and Dissertations

The Smackover Formation is the most prolific hydrocarbon producer in Alabama, with the Little Cedar Creek and Brooklyn Fields being the two largest producers in Alabama. Unlike other Smackover fields Little Cedar Creek Field and Brooklyn Field production is the result of two reservoirs, known as the shoal grainstone and thrombolite (microbial) boundstone. Even with the success of the Smackover Formation, geographic trends of the porosity and permeability are problematic because production is affected. The distribution of the facies also plays a role in the porosity and permeability. The objective of this study is to delineate porosity and permeability trends …

Land Cover Land Use Change And Soil Organic Carbon Under Climate Variability In The Semi-Arid West African Sahel (1960-2050), Amadou M. Dieye

Electronic Theses and Dissertations

Land Cover Land Use (LCLU) change affects land surface processes recognized to influence climate change at local, national and global levels. Soil organic carbon is a key component for the functioning of agro-ecosystems and has a direct effect on the physical, chemical and biological characteristics of the soil. The capacity to model and project LCLU change is of considerable interest for mitigation and adaptation measures in response to climate change. A combination of remote sensing analyses, qualitative social survey techniques, and biogeochemical modeling was used to study the relationships between climate change, LCLU change and soil organic carbon in the …

Simulating The Impacts Of Land-Use Land-Cover Changes On Cropland Carbon Fluxes In The Midwest Of The United States, Zhengpeng Li

Electronic Theses and Dissertations

Understanding the major drivers of the cropland carbon fluxes is important for carbon management and greenhouse gas mitigation in agriculture. Past studies found that agricultural land-use and land-cover (LULC) changes, such as changes in cropland production technologies, tillage practices, and planted crop species, could have large impacts on carbon fluxes. However, the impacts remain highly uncertain at regional to global scales. Satellite remote sensing is commonly used to create products with geospatial information on LULC changes. This geospatial information can be integrated into biogeochemical models to simulate the spatial and temporal patterns of carbon fluxes. We used the General Ensemble …

Perchlorate Variations Over 300 Years: Influence Of Human Activities, Volcanic Eruptions And Bolide Events, Kari Peterson

Electronic Theses and Dissertations

Perchlorate, which derives from both anthropogenic and natural sources in the current environment, constitutes a significant health risk to humans because it competitively inhibits iodine uptake by the thyroid gland. Thus, there has been considerable interest in reducing the human exposure to environmental perchlorate by limiting the release of perchlorate from anthropogenic sources. However, a lack of understanding of the relative contributions from anthropogenic and natural sources has prevented widespread regulation. A 300-year ice core perchlorate record from Summit Station, Greenland (1700-2007 C.E.) that extends beyond the onset of the Industrial Revolution (1850 C.E.) is used to assess the anthropogenic …

Contribution Of Shallow Geology To Hydrocarbon Seep Formation In Green Canyon Block 600, Samantha Lynn Lucker

Electronic Theses and Dissertations

The Green Canyon Federal Protraction area in the Gulf of Mexico is rich in hydrocarbons. The movement of the Sigsbee salt escarpment in green canyon has resulted in a complex bathymetric profile and extensive shallow faulting that has allomigration of hydrocarbons to the surface creating cold seep sites. Green Canyon block 600 (gc600) contains multiple naturally occurring, active hydrocarbon seeps. Multi-beam bathymetry, backscatter, and polarity preserving chirp data were collected for gc600 to study the development of these naturally occurring seeps. Using these data, the structure and sedimentation of the first fifty meters can be studied in relation to the …