Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis

Theses and Dissertations--Earth and Environmental Sciences

Iron meteorites remain the only material view into planetary cores. Despite their scientific relevance, iron meteorites are relatively rare. In June 2021 and March 2022, the Kentucky Geological Survey received requests to identify two metallic specimens discovered in central Kentucky. The specimens were given the provisional names Handys Bend (3175.2 g) and Flax Creek (286.2 g). The goal of this project is to confirm meteoritic origin, characterize their structures and chemistry, assign genetic classifications, and examine potential relations to previous discoveries. Petrography was conducted using scanning electron microscopy. Mineral phases were examined using X-Ray diffraction crystallography. Chemical compositions were determined …

Thermal Alteration Of The Mineralogy Of Calcium Sulfoaluminate Cements: Implications For The Performance Of Rapid Repair Materials, Jillian Cavellier

Theses and Dissertations--Earth and Environmental Sciences

Calcium sulfoaluminate (CSA) was developed in part to lessen the environmental impact of cementitious materials compared to traditional Portland cements. CSA was first put into production in the 1970s and has been undergoing various performance testing to investigate its durability. Yet to be evaluated is CSA’s response to a rapid, high temperature event. In this study, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectrometry and scanning electron microscope imaging were used to analyze alterations in the mineralogy due to such an event. As found in previous studies, after ~125°C, ettringite has been completely dehydrated. Ettringite decomposes into bassanite and calcium …

High Resolution Sedimentary Investigations Of Extant Lakes In North America, John Dilworth

Theses and Dissertations--Earth and Environmental Sciences

Investigation of past lake environments forms the discipline of paleolimnology. Paleolimnological studies seek to evaluate geophysical, geochemical, and ecological proxies and indicators contained within lake sediment archives. Using these potential stores of high-resolution environmental information, questions regarding climate, biological, and geochemical changes experienced by a lake and its watershed can be investigated. This dissertation research utilized lake sediment records from two lakes within North America to study different aspects of environmental change. This dissertation consists of three separate studies presented in three chapters.

Chapter Two presents a retrospective environmental assessment of Jackson Lake, Wyoming to investigate the impacts of dam …

Utilizing Isotope Tracing To Assess Land Use Implications To Tap And Stream Water Chemistry, Katrina Alexis Mcfadden

Theses and Dissertations--Biosystems and Agricultural Engineering

Water quality is an issue that continues to be worsened by extreme flooding, specifically in Eastern Kentucky. The most recent 2022 flooding event in Eastern Kentucky resulted in loss of human life, over $23.3 billion in damaged infrastructure, and impaired human health. Infrastructure failures, such as leaky pipes, are a growing challenge in these regions as rebuilding has occurred. Therefore, the goal of this project was to evaluate water quality in two of the counties most impacted by the 2022 flood in Kentucky, Breathitt and Perry Counties, using sulfur isotopes as a novel tracer to identify potentially failures in distribution …

Water Column Controls On Magnetic Mineral Formation And Preservation, Josephine Benson

Dartmouth College Master’s Theses

Iron-bearing minerals in the sedimentary record are frequently used to reconstruct past depositional environments. This is accomplished through geochemical, magnetic, and mineralogical analyses placed in geological context. These interpretations, however, depend on our understanding of how iron minerals form in nature. To better understand the formation of magnetic iron minerals in redox-stratified depositional settings, the study of modern analogs is crucial to unraveling environmental context no longer available from geological deposits. In this study, I utilized four anoxic and sulfidic stratified lakes within a 100-mile radius to examine the effects of small variations in lake properties on magnetic mineral formation …

Interconnectivity Of Melt During Partial Melting And Deformation Of A Peridotite, Jordan Collins

Williams Honors College, Honors Research Projects

The mechanisms that allow basaltic magma to be transported to the surface are well understood, but not much is known about how the transport channels form as the basalt melt forms at the source. I performed experiments to determine these mechanisms during general shear deformation of a natural olivine aggregate (dunite) from Anita Bay, New Zealand as it partially melts using a high pressure/temperature rock deformation apparatus. Samples were analyzed using the scanning electron microscope and I observed that melt pockets started to form at the grain scale (1-2 vol% melt) prior to becoming interconnected at the sample scale (3 …

An Experiment To Determine Mineral-Associated Organic Matter Turnover In A Sandy Clay Loam, Samantha Abel

All Master's Theses

Soil is an important terrestrial carbon sink. Through regenerative land management, which includes minimizing soil disturbance, the carbon content of soil can be raised towards preindustrial levels. This feat requires effectively storing carbon in a natural system that is inclined to cyclicity. The most stable form of soil organic matter is mineral-associated organic matter (MAOM). This carbon labelling experiment was designed to identify short-term CO₂ fluxes within the soil-plant-atmosphere system, particularly those related to MAOM turnover in the rhizosphere. Basil (Ocimum basilicum) was planted on a plot at the campus farm at Central Washington University. Another plot …

Eruption Initiation Mechanisms And Timescales At A Very-High-Threat Washington Volcano: Clues From Crystal Cargo In Lavas From Mount Baker (Koma Kulshan), Emily Yoder

All Master's Theses

Understanding the timescales of pre-eruptive processes is key for improving forecast models of future eruptions. Mount Baker (Koma Kulshan), WA, is part of the northern Cascade volcanic arc and classified as a very high threat volcano. However, we lack an understanding of the duration of time between the final magmatic process before eruption (potentially the process that initiated the eruption) and the eruption itself. This study focuses on (1) estimating eruption initiation timescales via diffusion chronometry and (2) determining eruption initiation mechanisms for three andesitic lava flows from Mount Baker: Dobbs Creek (~119 ka), Dobbs Cleaver (~105 ka), and Swift …

Timescales Of Magma Storage And The Pre-Eruptive History For The Most Recent Lava Flow At Mount Baker (Koma Kulshan), Wa, Desiree Cunningham

All Master's Theses

Mount Baker, ranked as a very-high threat volcano in the United States, is in a well-populated area in northern WA, putting many at risk in the event of a future eruption. Previous work on Mount Baker focused on understanding the magmatic architecture beneath the volcano and has identified multiple magmatic components that contributed to different eruptions throughout its history. The youngest lava flow in the Mount Baker Volcanic Field is the 9.8 ka Sulphur Creek lava flow. The last study conducted on this flow by Garvey (2022) determined the most recent magma mush configuration that was tapped for this eruption. …

Constraining Magma Oxidation State Through Zircon Trace Elements: Estimating Tungsten Mineralization Potential In Northeastern Washington, Robin Gaudette

All Master's Theses

The oxidation state of a magma (measured by oxygen fugacity, fO₂) controls what reactions are favored during crystallization and what elements are concentrated and potentially precipitated into minerals, making it a key factor in ore-forming processes as some commodity elements are best concentrated under specific redox conditions. Tungsten (W) is best concentrated under reducing magmatic conditions, a characteristic that makes constraining magma oxidation state, done through analysis of zircon trace elements, an essential tool in plutonic tungsten deposit exploration.

This research analyzes the zircon trace elements of several Cretaceous-age intrusions in the region surrounding the now-inactive Germania tungsten …

Petrologic And Geochemical Constraints On The Pre-Eruptive Storage Conditions Of Magmas Erupted During The ~12.5 Ka Flare Up Of Medicine Lake Volcano, Ca, Regina M. Khoury

Cal Poly Humboldt theses and projects

The Medicine Lake Volcano (MLV) system in the California Cascades is composed of a large shield volcano with numerous basaltic to rhyolitic vents on and around the flanks, many of which are aligned with N-S trending normal faults. A significant portion of the post-glacial volcanic activity at MLV is comprised of the ~12.5 ka “flare up” eruptions of basalt and basaltic andesite magmas from seven discrete flank vents. Prior work documented surface areas (0.02-198 km²), volumes (0.0001-4.35 km³), and eruption styles (Hawaiian to Strombolian; Donnelly-Nolan, 2010) of the ~12.5 ka deposits. This study uses new geologic …

Supporting Dataset For The Influence Of Tile-Water On Groundwater Nitrate Concentrations Within A Saturated Riparian Buffer Zone, Aminat Tosin Abdulsalam, Eric Wade Peterson

Faculty Publications - Geography, Geology, and the Environment

In the U.S. Midwest, where fertile soils with high water retention are prevalent, the installation of tile drainage networks have become a common practice to drain excess soil water, which enhances plant growth and increases crop productivity. However, tile drainage networks coupled with the use of inorganic fertilizers have significant implications on water quality, contributing to eutrophication, leading to harmful algal blooms, and resulting in hypoxic conditions in surface water bodies. To mitigate excess nutrient exports to surface water bodies, edge-of-field practices have been introduced. One such practice is the saturated riparian buffer (SRB), which utilizes a diversion system to …

Diatom Productivity And Nutrient Dynamics In The Ross Sea, Antarctica During Warm Events In The Neogene, Marialena Christopoulou

Graduate Research Theses & Dissertations

Increased melting of the Antarctic Ice Sheet (AIS) in recent decades, has had a significant impact on many aspects of the global ocean. Models indicate that by the end of the 21st century atmospheric carbon dioxide (CO2) concentrations may exceed 500 ppm, and the average global temperature will likely warm by more than 2°C. However, data that provide model constraints on potential feedbacks in ice-ocean-atmosphere system are limited by short-timescales (e.g., decadal- to centennial-scale) and incomplete spatial coverage. In particular, little is known about the impacts of future warming and widespread melting of AIS on marine biological productivity, silicate weathering …

Submarine Groundwater Discharge As A Major Nutrient Source In River-Fed Vs. Tidally Dominated Estuaries, Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

The tidal tributaries of the lower Chesapeake Bay experience seasonally recurring harmful algal blooms and the significance of submarine groundwater discharge (SGD) as a nutrient vector is largely unknown. Here, we determined seasonal SGD nutrient loads in two tributaries with contrasting hydrodynamic conditions, river-fed (York River) vs. tidally dominated (Lafayette River). Radon surveys were performed in each river to quantify SGD at the embayment-scale during spring and fall 2021. Total SGD was determined from a ²²²Rn mass balance and Monte Carlo simulations. Submarine groundwater discharge rates differed by a factor of two during spring (Lafayette = 11 ± 17 cm …

Geoelectrical And Hydrochemical Characterization Of Submarine Groundwater Discharge In Florida Bay, Ifeanyi Emmanuel Eze

College of Graduate Studies: Theses & Dissertations

Florida Bay, situated at the southern tip of Everglades National Park and underlain by the Miami Limestone formation, is an ecosystem of global significance. Over the past century, the bay has faced threats such as droughts, seagrass mortality, and hypersalinity. Despite various studies and management efforts, the dynamics of submarine groundwater discharge (SGD) in the region remain underexplored. Given that SGD plays a significant role in the chemical dynamics of coastal ecosystems, it warrants thorough investigation. This study aims to characterize the spatial and temporal patterns of SGD in Florida Bay by surveying three basins – Rankin, Whipray, and Rabbit …

A Petrographic And Geochemical Study Of The Rangataua Lava Flows, Mount Ruapehu, Aotearoa New Zealand, Lucy Smith

Scripps Senior Theses

Mount Ruapehu is a large stratovolcano on the North Island of Aotearoa New Zealand. The Rangataua lava flow is situated on the southern flanks of Ruapehu, and extends for 15-16 km. The flow is of andesite composition and comprised of three units: proximal, medial and distal. Mount Ruapehu is both scientifically and culturally significant.

Geochemical analyses of 13 whole rock samples, Electron Microprobe analyses of three polished thin sections, and geothermobarometry calculations were conducted to obtain data on pre-eruptive intensive parameters. Petrographic observations were used to investigate disequilibrium textures and shed light on magma chamber processes.

Results of this study …

10be Dating Of Last Glacial Maximum Moraines And Subsequent Glacial Retreat In Chirripó National Park, Costa Rica, Caleb Emeka Okpala

Dartmouth College Master’s Theses

During the Last Glacial Maximum (LGM; ~26-19 ka) and Termination 1 (~19-12 ka), the expansion and retreat of glaciers across the Southern and Northern Hemispheres, as well as other paleoclimate proxies, document a complex pattern of global climate change. While the timing and magnitude of LGM cooling and subsequent warming is relatively well constrained in mid- and high-latitude regions across both hemispheres, less information is available about climate changes in the tropics. To provide more information about tropical climate conditions during the LGM and Termination 1, I mapped and dated the extents of past glaciers in two valleys in Chirripó …

Coal As A Resource For Rare Earth Elements In West Virginia, Rachel Elizabeth Yesenchak

Graduate Theses, Dissertations, and Problem Reports (ETD)

Although rare earth elements and yttrium (REY) are essential for manufacturing technologies vital to economic and national security, the U.S. is heavily reliant on foreign imports of these critical metals. There is significant interest in identifying and developing unconventional REY resources including coal and coal-byproducts to help secure domestic supplies of these elements. Appalachian Basin coals and byproducts are particularly enriched in REY. Coal-producing states within the basin, including West Virginia, can utilize existing infrastructure and legacy coal mining wastes to transition into the production of REY. However, in order to develop these resources, it is critical to understand the …

Quantifying Chemical Erosion In The Lithologically-Heterogenous Appalachian Valley And Ridge, Amelia Jayne Zanoni

Graduate Theses, Dissertations, and Problem Reports (ETD)

Quantifying chemical erosion in the lithologically-heterogenous Appalachian Valley and Ridge

Amelia J. Zanoni

The interplay between physical and chemical erosion is well understood in landscapes underlain by a uniform rock type, but many regions are underlain by a mixture of rock types with varying erosion resistance and solubility. We used measurements of stream-water chemistry to estimate chemical erosion rates in the Appalachian Valley and Ridge, a region where the mechanisms of lithologic control over topography are poorly understood. Newly acquired stream water samples were collected from 51 locations across the research area during the Fall of 2023. The sampled waters …

Estimating Inorganic Carbon Flux From Coal Mining Discharge Portals In The Bituminous Coal Field Region Of Pennsylvania, Lauren J. Rockwell

Graduate Theses, Dissertations, and Problem Reports (ETD)

A fundamental driver of the adverse effects associated with coal mining is the interplay of water and oxygen within mined sites, leading to the creation of coal mine drainage (CMD). One often overlooked consequence of CMD is the release of geologically-bound carbon as carbon dioxide (CO₂). The interaction of CMD with carbonate rocks, specifically the presence of sulfuric acid driving the dissolution of these rocks, leads to the release of dissolved inorganic carbon (DIC). This study examined 25 CMD locations in an approximately 2,370 km² area within the bituminous coal field region of Pennsylvania (PA), specifically in …