Earth Sciences Commons^™

An Investigation Of Paleoclimate Through A Sedimentological Lens In The Gulf Of Mexico And Western North Pacific, Sarah Monica

Dissertations

This dissertation explores the use of sediment cores as proxy data for the reconstruction of paleoclimatic and environmental conditions. Human-caused climate change is leading to dramatic shifts in the global climate. As the instrumental record of climate is relatively short compared to the amount of time Earth has experienced weather, this work aims to extend our knowledge of climate beyond the instrumental record, thereby improving our holistic understanding of the climate system. In Chapter one, sediment cores from the central Texas inner shelf are used to produce a record of intense tropical cyclone (TC) activity over a ~4500-year period. X-Ray …

Advancements In Sinkhole Remediation: Field Data-Driven Sinkhole Grout Volume Prediction Model Via Machine Learning-Based Regression Analysis, Bubryur Kim, Yuvaraj Natarajan, K. R. Sri Preethaa, V. Danushkumar, Ryan Shamet, Jiannan Chen, Rui Xie, Timothy Copeland, Boo Hyun Nam, Jinwoo An

Civil Engineering Faculty Publications

Sinkhole formation poses a significant geohazard in karst regions, where unpredictable subsurface erosion often necessitates costly grouting for stabilization. Accurate estimation of grout volume remains a persistent challenge due to spatial variability, site-specific conditions, and the limitations of traditional empirical methods. This study introduces a novel machine learning-based regression model for grout volume prediction that integrates cone penetration test (CPT)-derived Sinkhole Resistance Ratio (SRR) values, spatial correlations between CPT and grouting points (GPs), and field-recorded grout volumes from six sinkhole sites in Florida. Three data transformation methods, the Proximal Allocation Method (PAM), the Equitable Distribution Method (EDM), and the Threshold-based …

East Antarctic Ice Sheet History At The Outback Nunataks Using Geographic Information Systems And Cosmogenic Dating, Jacob P. Baker

Electronic Theses, Projects, and Dissertations

This study investigates the history of ice sheet surface elevation at the Outback Nunataks in East Antarctica using exposure age dating and geomorphic mapping. We identified glacial landforms at Roberts Butte, Miller Butte, and Frontier Mountain, in the Outback Nunatak range, using 2023 Landsat Image Mosaic of Antarctica (LIMA) and 2022 Reference Elevation Model of Antarctica (REMA). We collected bedrock and glacial erratic samples for cosmogenic nuclide analysis from Roberts Butte and Miller Butte during the 2023-24 United States Antarctic Program field season. Analysis of glacial erratics reflect inherited cosmogenic nuclide concentrations, resulting in apparent exposure ages between 359 and …

Groundwater Arsenic Contamination In The Oro Grande Wash, Dalila Boice

Electronic Theses, Projects, and Dissertations

This study investigates the distribution of naturally occurring arsenic in groundwater within the Oro Grande Wash in San Bernardino County, California. Depth-discrete groundwater quality data were collected over multiple years using nested and Westbay monitoring wells. Water quality results showed higher levels of arsenic in the deeper aquifers, ranging between 600 feet and 1,000 feet below ground surface. Arsenic levels in these regions reached as high as 66 µg/L. At roughly 800 feet and below, water quality data from the wells reveal that arsenic concentrations exceeded the 10 µg/L maximum contaminant level (MCL) in 87% of cases. These data provide …

Interactions Between Black, Brown, Blue And Green Carbon From Terrestrial To Marine Ecosystems: A Critical Review, Allison White, Richard Kline, Md. Saydur Rahman

School of Earth, Environmental, & Marine Sciences Faculty Publications

Black and brown carbon are byproducts of the incomplete combustion of biomass or fossil fuels. These light-absorbing aerosols influence climate by altering the radiative balance through the absorption and scattering of sunlight, exacerbating global climate change. Their subsequent deposition on terrestrial and marine environments affects surface albedo, snow and ice melt, and biogeochemical processes, leading to further environmental consequences. In contrast, green and blue carbon refer to carbon stored in terrestrial vegetation and marine ecosystems, respectively. These ecosystems play a crucial role in mitigating climate change by sequestering atmospheric carbon; however, they are increasingly threatened by climatic disturbances, anthropogenic activities, …

Leptinotarsa Texana Schaeffer And Gargaphia Arizonica Drake & Carvalho As Potential Biocontrol Agents For The Noxious Weed Solanum Elaeagnifolium Cav, Samikshya Subedi, Stephanie L. Kasper, Alexis Racelis, Greg Lefoe, Rupesh R. Kariyat

School of Earth, Environmental, & Marine Sciences Faculty Publications

Silverleaf nightshade (Solanum elaeagnifolium Cav.; SLN) is a perennial forb native to the southern United States, Mexico and South America that has become a serious agricultural weed across the world. Biological control has emerged as a significant alternative for the management of (SLN) due to the challenges and high costs associated with chemical and mechanical controls. In this study, we used a combination of field and laboratory studies to (1) explore the fundamental and realized host ranges of two North American insects, Leptinotarsa texana Schaeffer and Gargaphia arizonica Drake & Carvalho and (2) assess their suitability as potential biological …

Spatial–Temporal Evolution Of The Box Springs Plutonic Complex, Riverside, Ca, Mateo Ospino Díaz

Loma Linda University Electronic Theses, Dissertations & Projects

The mechanisms of pluton emplacement into continental crust have long been debated in igneous geology, with early models emphasizing forceful processes such as ballooning, later contrasted by alternative emplacement mechanisms including diapirism, incremental assembly, stoping and, emplacement by sheets and dikes. These contrasting perspectives highlight the complexity of the construction of mid-crustal intrusions and the need for case studies that integrate multiple datasets. The Box Springs Plutonic Complex (BSPC) in the northern Peninsular Ranges Batholith (PRB) preserves structural, textural, and compositional features that record its emplacement and internal construction. Although its lithology, structure, and geochemistry have been described, an integrated …

Long-Term Sedimentation Rates And Patterns Of Alluvial Ridge Basins (Esteros) Of The Rio Grande Delta (Tx, United States Of America), Kynan Joseph Rutan

Theses and Dissertations

Little is known about the century-scale sedimentation rates and patterns of Alluvial Ridge basins within river deltas, especially in the Rio Grande Delta (RGD). To better constrain this, 22 cores were collected in the Bahia Grande Complex (BGC) and analyzed for grain size, organic content, age dates, and elemental composition.

Results show that grain size and sedimentation rates decrease from an artificial inlet to the basin interior, with elevated sedimentation in the south. Also, human activities, such as the construction of the Brownsville shipping channel in the 1930s, altered sedimentation dynamics in the basin by blocking natural inlets and leading …

Understanding Outer Solar System Ice Composition Through Impact Processes: Simulations And Hydrates, Jill Rebecca Mcdonald

Graduate Theses and Dissertations

This work concerns solar system ices, particularly water ice and clathrate hydrates. Water ice is abundant as a mineral in the outer parts of the solar system, providing source material for the formation of clathrates. We explored constituents through a combination of numerical modeling and laboratory experiments. Understanding the differences and similarities between these materials can shed light on planetary habitability, composition, and evolution. Chapter one contains relevant background information. This chapter introduces the ices that will be studied and gives insight into the locations of interest within our solar system. It also explains the mechanics of impact cratering processes …

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 …

The Effects Of Green Orientation And Technological Agility On Sustainable Competitive Advantage Under Environmental Uncertainty: Organizational Agility As A Pathway, Sahilali Saiyed, Vimal Kumar, Abdul Waaje, Adi Prasetyo Tedjakusuma

Michigan Tech Publications

Despite the strengthened efforts on sustainability and technological activities by firms, the existing literature lacks a clear picture regarding how green orientation (GO) and technological agility (TAG) can be transformed into sustainable competitive advantage (SCA) and at what time the conversion process may be most efficient. This paper conceptualizes organizational agility (OGA) based on the resource-based view (RBV) and dynamic capabilities theory (DCT) and hypothesizes that GO and TAG indirectly affect SCA with the mediating impact of environmental uncertainty (ELU). A moderated-mediation model was tested based on a sample of 200 managers (HR, marketing, accounting/finance, quality control, R&D) of auto-parts …

Tracing The Journey Of Dissolved Organic Matter: From Leaf Litter Photodegradation To Microbial Processing In Tropical Streams, Samantha Nicole Sullivan

Chemistry & Biochemistry Theses & Dissertations

Dissolved organic matter (DOM) is a major reservoir of organic carbon in aquatic ecosystems and plays a central role in global carbon cycling through its transformation and remineralization to carbon dioxide (CO₂). As DOM moves from terrestrial environments into streams and rivers, its chemical composition is altered by a combination of microbial and photochemical oxidation processes that regulate both its reactivity and its persistence during transport. However, the molecular mechanisms governing these oxidative transitions, particularly in tropical ecosystems characterized by strong hydrologic seasonality and substantial inputs of plant-derived material, remain insufficiently resolved. This dissertation integrates ultrahigh-resolution mass spectrometry, optical characterization, …

Aluminum As A Tracer Of Dust Deposition To The Ocean: A Case Study From The Bermuda Region, Tara Elizabeth Williams

OES Theses and Dissertations

Aluminum (Al), a major component of mineral aerosol (dust), partially dissolves in seawater and is widely used as a tracer for estimating time‐averaged dust fluxes to the ocean. Such estimates rely on dissolved Al (DAl) inventories in the surface mixed layer (SML), an assumed SML residence time of DAl (_TDAl), the fractional solubility of Al in dust (Al_S), and the mass fraction of Al in dust. In this study, dust flux estimated from seasonal, water-column DAl data from the Bermuda Atlantic Time-series Study (BATS) region are compared with direct dust flux estimated from contemporaneous measurements of …

Private Sand Mining In The Mississippi River: Sediment Budget And Morphology Implications Between Baton Rouge And Belle Chasse, Louisiana, Brett Mcmann

LSU New Orleans Theses and Dissertations

This analysis examined how private sand mining within the Mississippi River between Baton Rouge, LA and Belle Chasse, LA affected its sand budget from 2004-2012.

Records assembled indicated that private mining removed an annual average of 2.8 million cubic yards of sand. A HEC-RAS one-dimensional sediment transport model was utilized to assess this practice. Three scenarios were simulated: a baseline without mining, conditions reflecting documented mining rates, and a hypothetical case with excessive extraction.

Results suggest that private mining constituted approximately 26 percent of the total sand deficit between Baton Rouge and Belle Chasse. Mining appeared to cause localized changes …

Terrestrial And Lacustrine Organic Matter Biomolecular Transformations Via Thermal Maturation And Oxidative Degradation, Louis Connor Bondurant

Chemistry & Biochemistry Theses & Dissertations

The most abundant source of fossil fuel-forming kerogen on Earth is classified as Type II kerogen, believed to originate from marine biomass. However, a significant amount of lacustrine and terrigenous carbon is transported to the ocean through fluvial discharge. Less than half of the exported organic carbon is observed in coastal regions and the open ocean. There is a great need for an explanation of what is happening to this organic carbon during transport and deposition. Traditionally, the marine organic matter in coastal regions accumulates to eventually be buried and transformed into petroleum over millions of years due to its …

A Kinematic, Data-Parameterized Approach To Constrain Subducted Seafloor During The Emplacement Of Shatsky Rise, Alexzandrya Katrina Shotorban

OES Theses and Dissertations

This study investigates ridge spreading rates and plate boundary geometry in interactions between large igneous provinces and mid ocean ridges, and their role in the kinematics of Shatsky Rise, an undersea volcanic plateau in the western Pacific Ocean that is roughly the size of the state of California. Shatsky Rise formed at a ridge-ridge-ridge (RRR) triple junction (TJ) (Hilde et al., 1976; Sager et al., 1988), at the intersection of the Pacific-Izanagi, Pacific-Farallon, and Izanagi-Farallon ridges, beginning at approximately 147 Ma. Investigations into Shatsky Rise’s formation are limited by the fact that two-thirds of the seafloor data has subducted with …

Modern Water And Sediment Transport Patterns In Alluvial Ridge Basins Of The Rio Grande Delta, South Texas, Usa, Waqid Nabi

Theses and Dissertations

Alluvial ridge (AR) basins are shallow, marine-influenced depressions within river deltas, yet their flow and sediment dynamics remain poorly understood. This study examines hydrodynamics and sediment transport patterns in the Bahia Grande Complex, which are AR basins of the Rio Grande Delta, using tilt current meters, water-level and turbidity loggers, and suspended and bed-sediment sampling. The AR basins function as wind-dominated, microtidal environments, where pre-existing basin geometry and hydrodynamic forcings control water flow and sediment distribution patterns. Seasonal wind patterns and storms modulate water levels and flow connectivity. Substrate patterns reflect frequent resuspension in the shallow northern basin, maintaining coarse …

Evaluating Fall And Spring Planted Cover Crops For Integrated Management Of Herbicide Resistant Palmer Amaranth And Effect On Soil Health, Vipin Kumar

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Herbicide-resistant Palmer amaranth (Amaranthus palmeri S. Watson) pose a severe threat to agronomic crop productivity in the United States, including corn and soybean production in Nebraska. Therefore, there is an urgent need for diversified and sustainable management approaches. Integrating cover crops (CCs) with herbicide programs represents a promising strategy to achieve Palmer amaranth suppression, sustain crop yields, and contribute to long-term soil health in irrigated corn–soybean production systems in Nebraska.

A meta-analysis of 41 studies and 595 paired observations demonstrated that CCs reduced Amaranthus spp. density and biomass by 37–59% depending on the growing season, with grasses and mixtures …

Global, Continental, And Local Scale Paleoenvironmental Reconstruction Methods For Interpreting The History Of Miocene North America And The Great Plains, Willow Hue Nguy

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The Miocene of North America is characterized by dynamic changes in herbivore communities, habitat composition, and global climate. Long-term cooling and drying trends influenced large changes in floral and faunal communities. The Great Plains, North America shifted from closed-canopy biomes to open-canopy biomes with C3-grasses to biomes with C4-grasses. This shift affected the herbivore communities as browsing-adapted ungulates were replaced by grazing-adapted ungulates. Much focus has centered on the Great Plains, so it is not well understood how the changes in biomes compare to other regions of North America. The models used for vegetation density indicate open-canopy biomes since at …

Agricultural Practices’ Impact On Soil Health Indicators In Mid-South U.S. Crop Production Systems, Katherine Suzanne French

Graduate Theses and Dissertations

Soil health and regenerative agriculture are concepts gaining popularity across global agriculture systems. The effect of sustainable farming practices such as nutrient management, cover crops, adoption of no-tillage, and residue retention on crop yield, as well as environmental resilience, is increasingly being studied. This research aimed to evaluate the impacts of (i) cover cropping and nutrient management, and of (ii) soil sampling depth and timing on indicators of soil health in various mid-southern irrigated row crop systems. Soil health indicators like soil organic matter (SOM), carbon dioxide respiration (CDR), beta-glucosidase enzyme activity (BG), permanganate oxidizable carbon (POXC), and the soil …

Increasing Soil Health In Zero-Grade, Flood-Irrigated Rice In Eastern Arkansas, Hannah Elizabeth Vickmark

Graduate Theses and Dissertations

In an effort to build and maintain soil health and sequester soil C, many producers and researchers are turning towards regenerative management practices in agricultural systems, such as reduced tillage or no-tillage (NT), the implementation of winter cover crops (CC), and the use of organic or green manures, such as biochar. However, little research is being conducted on the long-term soil health and agronomic benefits of these practices in a flood-irrigated rice (Oryza sativa L.) production system. Three replications of seven treatment combinations were applied to 6.1 x 30.5 m rice plots. Baseline soil health properties were quantified at six …

Evidence Of Backwater Morphodynamics In Stratigraphy On Earth And Mars: Implications For Ancient Mars, Cory Mitchell Hughes

Graduate Theses and Dissertations

Geologic evidence indicates that liquid water once flowed in abundance across the martian surface. For this reason, in the search for evidence of extraterrestrial life, Mars represents a prime target for scientific inquiry. River systems encode climatic and environmental signals in their deposits on Earth and Mars, often in fan-shaped landforms (e.g., alluvial fans, river deltas, etc.). Distal fan-shaped deposits (i.e., river deltas), in particular, act as a relatively high-fidelity record of dynamic geologic processes. As such, NASA frequently sends rovers to locations on Mars’ surface with hypothesized river deltas (e.g., Perseverance and Jezero crater). Problematically, there are many different …

Updating The Surface Geological Maps In The Boston Mountains Region Of Arkansas Using Subsurface Well Log Correlation And Lidar Mapping, Olivia Smith

Graduate Theses and Dissertations

The Pennsylvanian Atoka Formation are the primary surface outcrops of the Boston Mountains in northwest Arkansas. Where fully preserved in the Arkoma Basin to the south, the Atoka Formation exceeds 18,000 feet of sandstone and shale. It is mapped as a single “undifferentiated” unit on the surface geological map of Arkansas. This project correlates ten subsurface subdivisions of the Atoka Formation plus the Desmoinesian to the surface outcrops of the southern Boston Mountains. This produced a higher resolution surface map beyond the current Atoka Undifferentiated scheme. Recognition of the Atoka Formation subdivisions in surface outcrops using standard lithostratigraphic and biostratigraphic …

Climate Change Has Increased Global Evaporative Demand Except In South Asia, Saeed Karimzadeh, Arman Ahmadi, Dennis Baldocchi, Joshua B. Fisher

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Climate change alters how strongly the atmosphere draws water from the land, yet a consistent global assessment of this evaporative demand has been lacking. Here, we analyze 45 years of climate data and global models to quantify trends in the key drivers—air temperature, humidity, radiation, wind speed, and cloud cover—that determine the atmosphere’s drying power. We find that evaporative demand has increased worldwide, indicating a stronger atmospheric thirst, except in South Asia, where it has declined. There, widespread irrigation has increased soil and air moisture, enhanced cloud formation, and reduced sunlight reaching the surface, counteracting the global signal. These contrasting …

High Variability In Flood Discharge And Stage Accelerates River Mobility, Chenliang Wu, Wonsuck Kim, Shuo Yang, Frank Tsai, Jeffrey A. Nittrouer, Tian Y. Dong, Duhwan Keum, Kyle M. Straub

School of Earth, Environmental, & Marine Sciences Faculty Publications

Lateral channel migration is a fundamental process in natural alluvial rivers; however, the factors that control the rate of migration remain unclear. Despite its importance in shaping river morphology, the impact of water discharge on river mobility is still largely unexplored. Here, we leverage a dataset of 64 rivers across the globe to show that higher variability in river discharge and stage promotes higher rates of river migration. To reveal the physical processes behind this relationship, we focused analyses on the lowermost 500 kilometers of the Mississippi River, where a pronounced gradient in water stage variability and migration rate exists. …

Phase Equilibria Modeling Constraints On Channel Flow Of Metasedimentary Crust Beneath The Southeastern Tibetan Plateau, Govind Joshi, Gregory Dumond

Geosciences Faculty Publications and Presentations

Lower crust of the southeastern Tibetan Plateau includes 100 s of km2-scale zones of low resistivity at 20-40 km-depths indicating the presence of melt +/- fluid +/- graphite. These zones coincide with interconnected zones of low shear wave velocity. Data from central and southeastern Tibet support the occurrence of meta-sedimentary felsic granulites in the lower crust along a backarc-like geothermal gradient. Phase equilibria modeling of average metasedimentary pelite and greywacke bulk compositions constrained by these geophysical data explored the impact of partial melting on shear wave velocity for a range of fluid content. Low shear wave velocities beneath southeastern Tibet …

An Objective Method To Locate Shear Lines During The Northeast Monsoon Season In The Philippines, Lyndon Mark P. Olaguera, John A. Manalo, Jun Matsumoto, Faye Abigail T. Cruz, Jose Ramon T. Villarin

SOSE Affiliate: Manila Observatory

The shear line is a narrow zone of maximum horizontal wind shear, typically identified as a confluence zone of low-level wind streams. Previous studies showed that this system can trigger heavy to extreme rainfall events in the Philippines during the northeast monsoon season. However, a research gap remains in objectively identifying and locating this system. Thus, this study develops a detection method that may be used for monitoring and forecasting the location of shear lines. Results show that the gradient of meridional winds in the y-direction (∂V925hPa/∂y), the boundary layer moisture flux convergence, and the 925 hPa relative vorticity may …

Controls On Speleothem Carbon Isotopes, Paloma Marcos

Undergraduate Research Symposium Posters

The Sistema Huautla cave system is the deepest known in the Western Hemisphere. It is located in the Sierra Mazateca Mountain Ranges near Jiménez de Huautla, Oaxaca. There are over 29 separately discovered entrances into this karst environment making it the 28th longest cave system in the world. It can be considered by some as one of the most complex vertical drainage systems on Earth. This extensive study site has been an area of interest among cavers and scientific researchers for nearly 6 decades. Speleothem samples from the study sites have been found to be over 433,000 years old. The …

The Relationship Between Lineaments And Cave Passages In Unfaulted Gently-Folded Strata, Snail Shell Cave, Central Tennessee, Usa, Mark Abolins, Joseph Firkaly-Paciera, Blake King, Cris Ocasio-Valentin, Jackson Slighter, Teagan Sullivan, Justin Whited

International Journal of Speleology

Near Snail Shell Cave in central Tennessee, USA, seven image interpreters independently mapped lineaments using a 3DEP LiDAR DTM, revealing geomorphic and structural differences in and near different parts of the cave. MANOVA comparison of lineament and cave passage trend for Western, Central, and Eastern Snail Shell caves reveals statistically significant differences (p <0.05). The Western cave (mean depth 44 m) is in the gently-dipping limb of the Snail Shell anticline, and the Central cave (mean depth 31 m) is in the anticline hinge. In contrast, many Eastern cave passages (mean depth 40 m) cut across the anticline hinge and part of the limb of the Overall syncline. For both the Western and Central caves, a post-hoc Tukey’s HSD test fails to show that lineament trend within 235 m of the cave differs significantly from passage trend, and the test fails to show that the two differ significantly within 235 and 433 m of the Eastern cave. Additional statistical testing fails to show a difference between Western passage trend and bed strike, indicating the likelihood that lineaments and passages developed within strike-joints. However, testing shows a statistically significant difference between passage trend and bed strike for the Central and Eastern caves. The strike of joints inside the Eastern cave shows that it is within a joint zone which penetrates to depths of at least 80 m and is expressed at the surface as an ~4.2 km-long belt of elevated lineament line density. The lack of a statistically significant difference between Eastern passage trend and the trend of a nearby topographic escarpment suggests that many joints are stress release fractures formed during relatively recent erosion. For the Eastern cave, intersections between lineaments and structures would be attractive targets for groundwater exploration at depths typical of wells in carbonates.

Characterization Of River Discharge And Interaction With Shallow Groundwater Aquifers Along The Wabash River Using Seismological Methods, Jessica M. Cyr, Xiaotao Yang, Marty D. Frisbee

Discovery Undergraduate Interdisciplinary Research Internship

The interaction between shallow aquifers and local rivers in the West Lafayette, Indiana area remains poorly understood. While surface water levels in the Wabash River and its tributaries are monitored at several USGS stream gauges, groundwater fluctuations are less well documented. Methods using seismic recordings, sensitive to subtle ground vibrations and subsurface structure, provide an alternative to characterize groundwater levels and river discharge. This project analyzes the temporal variations of ambient noise seismic data, examining the relationship to USGS river discharge, precipitation records, and other environmental factors. We currently focus on 1) changes in maximum amplitudes and peak frequencies within …