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Articles 1081 - 1110 of 29939

Full-Text Articles in Geology

Earth Analogue Analysis Of Volcanic/Tectonic Interactions With Applications To Venusian Stresses, Michael Ortigoza May 2025

Earth Analogue Analysis Of Volcanic/Tectonic Interactions With Applications To Venusian Stresses, Michael Ortigoza

Theses and Dissertations

Venus shares many geological similarities with Earth, yet its tectonic processes and magma injection mechanisms remain poorly understood. A key question in planetary geology is how effusive volcanism persists despite the intense horizontal compression terrestrial bodies experience over time. To explore these issues, we examine the Spanish Peaks dike swarm in Colorado which serves as an ideal site for investigating magma intrusion under compressive stress conditions. Through field mapping, orientation measurements, and structural analysis, we identify a strong relationship between pre-existing joints and dike orientations, suggesting that these fractures serve as critical magma pathways in compressive regimes. Additionally, evidence of …


Insights Into Fluid-Rock Interactions On The Cv3 Chondrite Parent Body Through The Use Of Secondary Garnets In The Allende Cv3 Chondrite And Terrestrial Skarns, Jessica Marie Johnson May 2025

Insights Into Fluid-Rock Interactions On The Cv3 Chondrite Parent Body Through The Use Of Secondary Garnets In The Allende Cv3 Chondrite And Terrestrial Skarns, Jessica Marie Johnson

Earth and Planetary Sciences ETDs

Garnets are valuable for studying geologic processes, particularly fluid-rock interactions in terrestrial skarns. This dissertation examines secondary garnets and associated Ca-Fe silicates in Allende-like CV3 chondrites and terrestrial skarns to assess garnets as recorders of fluid-rock interactions. Chapter 2 investigates garnets from the Willsboro-Lewis skarn, revealing that mineral separate techniques misrepresent rare earth element (REE) signatures. Chapter 3 examines garnets and clinopyroxenes from the Victorio Mining District skarn, showing that REE incorporation was controlled by fluid composition rather than crystal chemistry. Chapters 4 and 5 focus on extraterrestrial samples. Chapter 4 finds that garnets and pyroxenes in Allende CV3 matrix …


Visualization Of Coastal Carbonate Lithosomes: Color-Intensity Patterns And Georadar Imaging Of A Semi-Lithified Strandplain, Eleuthera Island, The Bahamas, Ilya Buynevich, Michael Savarese, H. Allen Curran May 2025

Visualization Of Coastal Carbonate Lithosomes: Color-Intensity Patterns And Georadar Imaging Of A Semi-Lithified Strandplain, Eleuthera Island, The Bahamas, Ilya Buynevich, Michael Savarese, H. Allen Curran

Geosciences: Faculty Publications

Quaternary carbonate strandplains serve as archives of land–sea interaction, including the impacts of storms and tsunamis. Incipient lithification, especially of compound beach/dune ridges within the action zone of salt spray, presents challenges to geological research, which is often limited to exposures. This study combines aerial image analysis with geophysical datasets to assess the morphostratigraphy and internal structure of the Freedom Beach Strandplain along southern Eleuthera Island, The Bahamas. Color-intensity analysis of field photographs and satellite images revealed general patterns that can be used to distinguish between areas with different grayscale parameters (sand-covered surfaces, lithified ridges, vegetation, etc.). Cross-shore (dip-section) high-resolution …


Proceedings Of The 12th Research Symposium At Mammoth Cave National Park, Pat Kambesis Editor, Lee Anne Bledsoe Editor, Ana K. Celis Editor May 2025

Proceedings Of The 12th Research Symposium At Mammoth Cave National Park, Pat Kambesis Editor, Lee Anne Bledsoe Editor, Ana K. Celis Editor

Mammoth Cave Research Symposia

Proceedings of the 12th Research Symposium at Mammoth Cave National Park: Celebrating 100 Years of Scientific Research & Resource Management in the Mammoh Cave Region.


Evaluating Subduction Zone Processes In Early Paleozoic Rocks Of The Northern Appalachian Orogen, John Mark Brigham May 2025

Evaluating Subduction Zone Processes In Early Paleozoic Rocks Of The Northern Appalachian Orogen, John Mark Brigham

Dissertations - ALL

The study of rocks presently exposed at the surface in mountain ranges such as the Appalachian Mountains can offer insight into the evolution of orogenic and subduction zone processes over geologic time. To better understand the timing, conditions (i.e., pressure and temperature), and tectonic setting of mineral formation in former subduction settings, geologists conduct geochronology, geochemistry, and thermobarometry analyses on rocks and minerals in paleo-subduction zones. This dissertation contains three chapters that focus on serpentinization, hydrothermal alteration of mafic rocks during serpentinization (rodingitization), and high-pressure metamorphism that occurred in a subduction setting during the first phase of the Appalachian Orogeny. …


Magma Evolution And Eruptive History Of Three Fingered Jack: A Mafic Composite Volcano In The Central High Cascades Of Oregon, Javaria Aziz May 2025

Magma Evolution And Eruptive History Of Three Fingered Jack: A Mafic Composite Volcano In The Central High Cascades Of Oregon, Javaria Aziz

Dissertations and Theses

The central High Cascades graben in Oregon has been a center for mafic volcanism since its initiation. Three Fingered Jack is one of the larger mafic composite cones in the graben, located 20km south of Mount Jefferson. Three Fingered Jack erupted between 142.1 - 150.8ka, based on Ar40/Ar39 age dates. This study provides stratigraphic, compositional and petrographic evidence to understand the eruptive history of Three Fingered Jack and the processes involved in generating compositionally diverse basaltic andesites here.

The basaltic andesites of Three Fingered Jack show three compositional trends of magma evolution: 1) enrichment, 2) depletion and …


Recent U.S. Government Policy Literature On Critical And Strategic Minerals, Bert Chapman May 2025

Recent U.S. Government Policy Literature On Critical And Strategic Minerals, Bert Chapman

Libraries Faculty and Staff Scholarship and Research

Critical and strategic minerals have become increasingly important in U.S. government civilian and military policymaking in recent years. This is demonstrated by the heavy use of such minerals in many critical civilian and military infrastructures. This work will discuss how this subject has been addressed in laws, presidential documents, and works by government agencies along with congressional oversight committees and support agencies. It will stress how the United States is heavily dependent on strategic minerals from adversarial foreign countries such as China and will examine U.S. efforts to increase its ability to produce such materials in the United States by …


Survey Of A Paired Gravity Anomaly Within The Benton Uplift Of The Ouachita Mountains, Isaac B. Prud'homme May 2025

Survey Of A Paired Gravity Anomaly Within The Benton Uplift Of The Ouachita Mountains, Isaac B. Prud'homme

Physics Undergraduate Honors Theses

The Benton Uplift west of Hot Springs, AR is underlain by a paired gravity anomaly on the order of 80 mGal. Nicholas & Rozendal (1975) have theorized that the gravitational low is caused by a “downwarp of the crust into the mantle”1 however the cause of the gravitational high is still debated. This paired gravity anomaly within the Benton Uplift follows the Ouachita orogenic belt southwest for 500 miles where it meets the Marathon uplift in southwest Texas. We conducted a gravity survey along a 108-km-long transect east of two previous gravity surveys.2,3 We corrected the data from this transect …


Unraveling The Causal Influences Of Drought And Crop Production On Groundwater Levels Across The Contiguous United States, Nitin K. Singh, Sheila M. Saia, Ruchi Bhattacharya, Hoori Ajami, David M. Borrok May 2025

Unraveling The Causal Influences Of Drought And Crop Production On Groundwater Levels Across The Contiguous United States, Nitin K. Singh, Sheila M. Saia, Ruchi Bhattacharya, Hoori Ajami, David M. Borrok

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Groundwater depletion in agricultural-dominated regions is attributed to climate and irrigation withdrawals that support crop production. However, despite decades of effort, knowledge gaps remain in understanding the relative influence of drought and crop production on groundwater levels at the continental scale. Here, utilizing empirical observations, we simultaneously track how long-term trajectories of groundwater levels, crop production of seven crops, and drought have evolved over time, and then integrate these observations with a causality-based attribution framework to unravel the relative impact of drought and crop production on groundwater levels across the contiguous United States (CONUS). We find a dominant pattern of …


Characterization Of Residual Mineral Content Of Bauxite Stockpiles In Saline County, Arkansas: An Xrd Analysis Approach, Andrew Kaze Sezibera May 2025

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 …


Earthscape Ai Dataset V1.1, Matthew Massey, Abdullah-Al-Zubaer Imran May 2025

Earthscape Ai Dataset V1.1, Matthew Massey, Abdullah-Al-Zubaer Imran

Research Data--KGS

EarthScape v1.1 Dataset Download Links:

esv1p1_smokeset.zip (197 MB)

esv1p1_splits.zip (2.5 MB)

esv1p1_usa_ky_data.zip (1 MB)

esv1p1_usa_ky_hardin_howevalley.zip (26.3 GB)

esv1p1_usa_ky_hardin_sonora.zip (26.3 GB)

esv1p1_usa_ky_warren.zip (166 GB)

Surficial geologic mapping is essential for understanding Earth surface processes and supporting applications in engineering, hazard assessment, and resource management. However, traditional mapping approaches are labor-intensive, limiting spatial coverage and introducing subjectivity. To address these challenges, we introduce EarthScape, a multimodal, AI-ready geospatial dataset designed for surficial geologic mapping and Earth surface analysis. EarthScape integrates high-resolution aerial RGB and near-infrared (NIR) imagery, digital elevation models (DEM), multi-scale terrain features derived from DEMs, and hydrologic and infrastructure vector …


Comprehensive Global Data Set Of Uniformly Processed Shear-Wave Splitting Measurements, Jonathan Wolf, Thorsten W. Becker, Edward Garnero, Kelly H. Liu, John D. West May 2025

Comprehensive Global Data Set Of Uniformly Processed Shear-Wave Splitting Measurements, Jonathan Wolf, Thorsten W. Becker, Edward Garnero, Kelly H. Liu, John D. West

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Seismic anisotropy can inform us about convective flow in the mantle. Shear waves traveling through azimuthally anisotropic regions split into fast and slow pulses, and measuring the resulting shear-wave splitting provides some of the most direct insights into Earth's interior dynamics. Shear-wave splitting is a constraint for path-averaged azimuthal anisotropy and is often studied regionally. Global compilations of these measurements also exist. Such compilations include measurements obtained using different data processing methodologies (e.g., filtering), which do not necessarily yield identical results, and reproducing a number of studies can be challenging given that not all provide the required information, for example, …


Evidence For Distal Bolide Impact And Tsunami Deposits In The Upper Atlantic Coastal Plain Of Moore County (North Carolina, Usa) Generated By The Eocene Chesapeake Bay Bolide Impact, G. Robert Ganis, Ralph H. Willoughby, David J. Cicimurri, G. Richard Whittecar, Steven J. Hageman May 2025

Evidence For Distal Bolide Impact And Tsunami Deposits In The Upper Atlantic Coastal Plain Of Moore County (North Carolina, Usa) Generated By The Eocene Chesapeake Bay Bolide Impact, G. Robert Ganis, Ralph H. Willoughby, David J. Cicimurri, G. Richard Whittecar, Steven J. Hageman

OES Faculty Publications

Beds interpreted as Eocene bolide-generated impact and tsunami deposits occur at Paint Hill in the Upper Atlantic Coastal Plain of Moore County, North Carolina, USA. These strata, herein named the Mount Helicon Formation, consist of four distinct beds comprising about one meter of total section. Bed 1 (the basal bed) is approximately 43 cm thick and consists of sandy carbonaceous clay with carbon glass and rock fragments and contains 14-18 parts per billion (ppb) iridium (interpreted as bolide impact ejecta). Bed 2 is approximately 9 cm thick and consists of non-cohesive silt-size particles and loosely bound sand-size accretionary lapilli-like masses …


Lidar-Based Delineation Of Karst Features In The Gypsum Plain, Eddy County, New Mexico And Culberson County, Texas, Kaitlyn Rae Levassar May 2025

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 May 2025

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 …


From Land To Lagoon: The Spatiotemporal Biogeochemical Dynamics Of Arctic Coastal Erosion In Elson Lagoon, Alaska, Sasha Victoria Peterson May 2025

From Land To Lagoon: The Spatiotemporal Biogeochemical Dynamics Of Arctic Coastal Erosion In Elson Lagoon, Alaska, Sasha Victoria Peterson

Open Access Theses & Dissertations

TThe Arctic is warming rapidly, driving widespread environmental change across coastal landscapes, including permafrost thaw, shoreline erosion, and shifts in sediment and carbon dynamics, pose growing challenges for predicting carbon cycling and climate feedbacks. This dissertation investigates the spatiotemporal variability of erosion, decomposition, and nearshore turbidity in Elson Lagoon, Alaska (1955–2023), to better understand how carbon, nitrogen, and sediment are mobilized, transformed, and potentially emitted as greenhouse gases in Arctic coastal systems. Chapter 2 presents a high-resolution analysis of shoreline change and erosion-driven material fluxes spanning nearly seven decades. Drawing on 795 soil data points, airborne LiDAR, and five shoreline …


Sediment And Debris Flows Resulting From The 2020 El Dorado Wildfire, San Bernardino Mountains, California, Andrew Suarez May 2025

Sediment And Debris Flows Resulting From The 2020 El Dorado Wildfire, San Bernardino Mountains, California, Andrew Suarez

Electronic Theses, Projects, and Dissertations

The Yucaipa Ridge is a section of the San Bernardino Mountains within the Transverse Ranges of Southern California. During the summer and early fall of 2020, Yucaipa Ridge experienced severe vegetation damage from both the Apple and El Dorado wildfires. Burned slopes exhibit a higher susceptibility to geomorphic change within several years of burning from the introduction of meteoric water onto the slope. Yucaipa, Oak Glen, and other nearby communities are currently at risk of damage by hyperconcentrated flows and debris flows during the seasonal rainy season.

Debris flows and hyperconcentrated flows (a.k.a. mudflows; are grouped and referred to in …


A Mineralogical And Geochemical Investigation Of The Influence Of Tectonic Setting On Accessory Mineral Assemblages In Serpentinites Along The Western North American Margins, Bryan H.T. Seymour May 2025

A Mineralogical And Geochemical Investigation Of The Influence Of Tectonic Setting On Accessory Mineral Assemblages In Serpentinites Along The Western North American Margins, Bryan H.T. Seymour

Electronic Theses, Projects, and Dissertations

Serpentinites are metamorphic rocks typically produced by hydrating mantle peridotites to form assemblages containing one or more serpentine minerals. They occur in various tectonic and geologic settings, such as submarine hydrothermal systems, ophiolite sequences, and the forearc mantle. Serpentinites are associated with highly reduced conditions, as indicated by low oxygen fugacity (ƒO₂) values. Previous investigations suggest that oxygen fugacity varies with tectonic setting due to differences in environmental conditions. To test this hypothesis, we analyzed serpentinites from a wide variety of tectonic settings in western North America: The New Idria forearc diapir (CA), Canyon Mountain Island arc complex (OR), Josephine …


Degradation Of Martian Glacier-Like Forms In Relation To The Observed Evolution Of Emmons Glacier On Mount Rainier, Wa, Jose E. Jimenez May 2025

Degradation Of Martian Glacier-Like Forms In Relation To The Observed Evolution Of Emmons Glacier On Mount Rainier, Wa, Jose E. Jimenez

Electronic Theses, Projects, and Dissertations

This study establishes parallels between the observed degradational evolution of debris-covered glaciers on Mount Rainier, WA and select glacier-like forms (GLFs) by studying the time-varying morphologies of the debris cover. Mount Rainier is home to 28 debris-covered valley glaciers, including Emmons Glacier which has a history of orthoimages taken from 1951 to 2023 and high-resolution Digital Elevation Model (DEM) coverage of 2008, 2021 and 2022. We can observe the degradational evolution of Emmons Glacier through orthorectified black and white imagery collected from an airborne platform and the National Agricultural Imagery Program (NAIP) colored satellite images periodically collected over the last …


Geochemical Analysis For Potential Critical Mineral Resources In Carbon Fly Ash, Korei D. Patterson Teer May 2025

Geochemical Analysis For Potential Critical Mineral Resources In Carbon Fly Ash, Korei D. Patterson Teer

Graduate Theses and Dissertations

The growing demand for critical minerals, coupled with the increasing supply chain vulnerabilities, has intensified the need for alternative domestic resources of critical minerals beyond traditional mining. Many of these critical minerals are essential for advanced technologies, energy storage, and national security, yet the United States remains heavily dependent on foreign imports, particularly from China. This study evaluates the economic potential of critical mineral recovery from Carbon Fly Ash (CFA), a byproduct of coal combustion, to determine its viability as a secondary source of critical minerals. A geochemical and mineralogical assessment was conducted on CFA samples from various storage sites …


Post-Fire Debris Flow Initiation Potential Based On Forensic Analysis Of Debris Flow Occurrence From The 2020 El Dorado Wildfire On Yucaipa Ridge, San Bernardino County California, Seth Clemen D. Saludez May 2025

Post-Fire Debris Flow Initiation Potential Based On Forensic Analysis Of Debris Flow Occurrence From The 2020 El Dorado Wildfire On Yucaipa Ridge, San Bernardino County California, Seth Clemen D. Saludez

Electronic Theses, Projects, and Dissertations

This study focuses on the potential debris flow initiation and effect in areas affected by the El Dorado Fire in the Southern San Bernardino Mountains. It uses novel technology combining drone-based photography and LiDAR imaging to create surface models of areas where potential debris flows could initiate, flow, and be deposited. The scans were repeated as geomorphic change occurred through the wet season to document spatial and volumetric changes resulted from the flows. These measurements were combined with traditional fire assessment and observational methods to characterize pertinent conditions.

As we investigated potential debris flow risk in this study area, we …


The Petm: A Window Into Earth's Future Climate, Jacalyn M. Wittmer Malinowski May 2025

The Petm: A Window Into Earth's Future Climate, Jacalyn M. Wittmer Malinowski

Climate Change and the Individual, 2025-26

The Paleocene-Eocene Thermal Maximum (PETM) is not just an event that occurred in Earth’s distant past (~55 million years ago) but is a crucial lesson for today’s meteoric climate change. The PETM offers a historical parallel of rapid flux of greenhouse gases into the atmosphere that caused global warming, ocean acidification, dramatic changes in weather, and extinctions. This global warming event was the result of 20,000 years of “rapid” warming (in geological terms) however, we are experiencing rates of warming that are 5-10x higher than PETM levels. We are not experiencing rapid warming today, in comparison to the past, we …


The Human Legacy: Agriculture, Civilizations, Strife, And Pandemics Changing Our Climate, Jacalyn M. Wittmer Malinowski May 2025

The Human Legacy: Agriculture, Civilizations, Strife, And Pandemics Changing Our Climate, Jacalyn M. Wittmer Malinowski

Climate Change and the Individual, 2025-26

For most of human history, climate has shaped our lives, while our influence on it remained minimal. However, the notion that early humans had no measurable impact on the climate before industrialization is inaccurate. Early in human history, activities – such as the rise of agriculture, the growth of civilizations, periods of conflict, and pandemics – altered greenhouse gas levels in the atmosphere. These changes contributed to significant periods of climate change long before the burning of fossil fuels set us on the path to today’s global climate crisis.


The 1991 California 'Miracle March': Precipitation Myth Or Miracle?, Cody D. Poulsen, Rachel E.S. Clemesha, Ian M. Howard, Alexander Gershunov, Michael D. Dettinger, Zhenhai Zhang, Rosa Luna-Nino, David W. Stahle, Ralph F. Martin May 2025

The 1991 California 'Miracle March': Precipitation Myth Or Miracle?, Cody D. Poulsen, Rachel E.S. Clemesha, Ian M. Howard, Alexander Gershunov, Michael D. Dettinger, Zhenhai Zhang, Rosa Luna-Nino, David W. Stahle, Ralph F. Martin

Geosciences Faculty Publications and Presentations

The term 'Miracle March' is colloquially used in California to describe an anomalously wet spring that alleviates drought conditions caused by a winter precipitation deficit. This study centers on the influential water year 1991, which is the standard reference point for this phenomenon. The spring precipitation impact on water year totals and the geographic extent of the spring precipitation anomaly during the 1991 'Miracle March' (MM91) is without equal in the observational record. This exceptional precipitation episode was initiated by a week-long sequence of extreme atmospheric rivers that started landfalling on February 27th. To this day, MM91 is routinely referenced …


Insights From Automated Mineralogic Analysis Of Modern Sand, Quinten Jones May 2025

Insights From Automated Mineralogic Analysis Of Modern Sand, Quinten Jones

Graduate Theses and Dissertations

Methods for determining and categorizing the modal compositions of sand and sandstone have long been a subject of debate in the field of sedimentary geology. Point counting is the most commonly used technique for determining modal compositions from petrographic slides, which are then categorized based on relative proportions of quartz, feldspar, and rock (or lithic) fragments. However, this approach fails to adequately preserve relevant textural data, such as grain size and sorting, which play an important role in diagenesis and in influencing reservoir quality. Additionally, the categorical nature of point counting results in a lack of specificity and loss of …


A New Method Using Lidar And Well Logs To Identify And Correlate The Pennsylvanian Atoka Formation Subdivisions In The Surface Outcrops Of The Boston Mountains, Arkansas, Robert Brent Boyd May 2025

A New Method Using Lidar And Well Logs To Identify And Correlate The Pennsylvanian Atoka Formation Subdivisions In The Surface Outcrops Of The Boston Mountains, Arkansas, Robert Brent Boyd

Graduate Theses and Dissertations

The surface outcrops of the Boston Mountains in northwest Arkansas primarily consist of the Pennsylvanian Atoka formation. Where fully preserved in the Arkoma Basin to the south, the Atoka formation exceeds 18,000 ft of sand and shale. However, it remains undifferentiated on the surface geological map of Arkansas. This study investigates the possibility of identifying and correlating the subsurface subdivisions of the Atoka Formation to the surface outcrops of the Boston Mountains using a new method. Recognizing the Atoka subdivisions in surface outcrops using standard lithology and biostratigraphy correlation techniques has been challenging. The subdivision of the Atoka has instead …


Reevaluating The Drumian Carbon Isotope Excursion (Dice) In Western-Central Utah, Michelle M. Norman May 2025

Reevaluating The Drumian Carbon Isotope Excursion (Dice) In Western-Central Utah, Michelle M. Norman

Undergraduate Honors Capstone Projects

The Drumian Stage of the Cambrian Period is defined by the First Appearance Datum (FAD) of the cosmopolitan trilobite Ptychagnostus atavus in 504.5 Ma strata deposited on the slope and shelf of the Laurentia margin. The Drumian Global Stratotype Section and Point (GSSP), showing the best preserved example of P. atavus compared to global outcrops, is defined in the Drum Mountains of west-central Utah. Due to the inconsistent nature of fossil preservation, researchers have sought secondary proxies to identify Drumian-aged strata in the absence of age-diagnostic fauna. One key proxy is the Drumian Carbon Isotope Excursion (DICE), an ~-2.5‰ carbon …


Leveraging Machine Learning Models For Enhanced Landslide Prediction In Western North Carolina, Andrew Edmonds May 2025

Leveraging Machine Learning Models For Enhanced Landslide Prediction In Western North Carolina, Andrew Edmonds

Graduate Theses and Dissertations

Landslides pose significant hazards to human safety, infrastructure, and the environment, particularly in regions of high elevation that experience extended periods of heavy rainfall. This research focuses on preparing and evaluating landslide susceptibility maps (LSMs) for the Blue Ridge Mountains, a portion of the Appalachian Mountains in western North Carolina, utilizing three machine learning algorithms: Logistic Regression, Random Forest, and Gradient Boosting Regression. Sixteen landslide conditioning factors, reflecting topographic, geological, environmental, and anthropogenic influences, were identified for model input. The landslide inventory database, comprising 7,350 locations, was randomly divided into training (80%) and testing (20%) sets. The performance of each …


Older Groundwater Reservoirs In Nebraska, Marvin P. Carlson, Steven S. Sibray Apr 2025

Older Groundwater Reservoirs In Nebraska, Marvin P. Carlson, Steven S. Sibray

Conservation and Survey Division: Faculty and Staff Publications

Sedimentary rocks below Nebraska's regional water table are saturated down to the crystalline igneous and metamorphic rocks of Precambrian age. The total thickness of these sedimentary rocks ranges from about 600 feet to over 10,000 feet. Nearly all current wells in Nebraska produce water from the near-surface, unconsolidated or partly consolidated rocks. Most studies to date -- interpretive reports, test drilling, inventory of wells, monitoring water levels, and water quality determinations -- have concentrated on these near-surface sources of groundwater.


Extracting Metamorphic Histories Utilizing U-Pb Laser Ablation Zircon Geochronology From The Southern Appalachians Crystalline Rocks And Detrital Sediment, Meredith Kay Love Gawai Apr 2025

Extracting Metamorphic Histories Utilizing U-Pb Laser Ablation Zircon Geochronology From The Southern Appalachians Crystalline Rocks And Detrital Sediment, Meredith Kay Love Gawai

Theses and Dissertations

The southern Appalachian mountain belt is an accretionary orogen that formed in the southeastern United States through several phases of oceanic subduction and continental collision during the Paleozoic Era and culminated in the formation of the supercontinent Pangaea. Although many U-Pb zircon ages have been collected from the igneous, metaigneous and metasedimentary rocks in the crystalline core of the southern Appalachians, there remain opportunities to better reconstruct the metamorphic and magmatic history of the southern Appalachians through the lens of zircon geochronology. Such data are valuable in identifying genetic relationships between candidate terranes of the orogen. Herein, I present laser-ablation …