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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
Petrology, Geochemistry, And Experimental Studies Of Mafic Enclaves And Amphibole At Shiveluch Volcano, Kamchatka, Andrea Elizabeth Goltz
Petrology, Geochemistry, And Experimental Studies Of Mafic Enclaves And Amphibole At Shiveluch Volcano, Kamchatka, Andrea Elizabeth Goltz
Arts & Sciences Electronic Theses and Dissertations
This thesis connects mineralogical, chemical, and physical observables in quenched mafic inclusions from Shiveluch Volcano in Kamchatka and high pressure and temperature experiments to elucidate the water content of primitive magmas at Shiveluch, the timing of magmatic recharge events relative to eruption, and the petrogenetic history of andesites erupted at Shiveluch. Using the petrology of basaltic andesite mafic inclusions erupted from Shiveluch, in Chapter 2, the water content of primitive magmas at Shiveluch is found to be 8-10 wt%, which is two to three times higher than the global average determined by other methods, and the temperature of primitive magmas …
Iron And Manganese Oxidation By Oxyhalogen Species: Implications For Paleoenvironmental Reconstruction On Mars, Kaushik Mitra
Iron And Manganese Oxidation By Oxyhalogen Species: Implications For Paleoenvironmental Reconstruction On Mars, Kaushik Mitra
Arts & Sciences Electronic Theses and Dissertations
As the nearest planetary neighbor with potential earlier habitable conditions, Mars is replete with minerals that hold clues to its past chemistry and evolution of the aqueous systems. Oxidized iron (Fe) and manganese (Mn) minerals on Mars are geochemical markers of such environments in which they formed and record past pH, redox conditions, and intensity of water-rock interaction. Fe and Mn oxides can therefore be used to reconstruct past Martian environmental conditions from settings where aqueous fluids were active. Various processes that form Fe and Mn oxide minerals on Mars have been previously proposed, including chemical oxidation using molecular oxygen …
Landscape Evolution At Endeavour And Gale Craters On Mars, And How Terrain Characteristics Correlate With Mineralogy On Lower Mount Sharp, Gale Crater, Madison Nicole Hughes
Landscape Evolution At Endeavour And Gale Craters On Mars, And How Terrain Characteristics Correlate With Mineralogy On Lower Mount Sharp, Gale Crater, Madison Nicole Hughes
Arts & Sciences Electronic Theses and Dissertations
The geomorphic expression of terrain provides information such as the underlying lithologic properties and the dominant surface processes. By examining the surface morphology of two impact craters on Mars that have been explored by rovers, we can synergistically combine orbital and ground observations to obtain a deeper insight into the geologic history. In this dissertation, we analyze the landscape evolution of Endeavour and Gale craters, which have been explored by the Opportunity and Curiosity rovers, respectively. This is accomplished largely by analyzing the topography on a larger scale using images from Mars orbiters and their associated Digital Elevation Models, combined …
Internal Structures And Spin Evolutions Of Small Bodies In The Solar System And Their Geophysical Implications: A Case Study On Ceres, Vesta, And Arrokoth, Xiaochen Mao
Arts & Sciences Electronic Theses and Dissertations
Asteroids and Kuiper belt objects are for the most part the remnant planetesimals that have not been able to form into planets. These small bodies’ evolutionary pathways encode information from the early days of the Solar System. Recent space missions such as Dawn and New Horizons have now made detailed geological investigations of small bodies (i. e. , Ceres, Vesta, and Arrokoth) possible. In this thesis, I use geophysical modeling to study small body internal structure and to investigate spin history under the influence of impacts. I analyze the gravity and shape data obtained by Dawn of Ceres and make …
Seismicity And Shallow Structure At The Mariana Subduction Zone, Melody Eimer
Seismicity And Shallow Structure At The Mariana Subduction Zone, Melody Eimer
Arts & Sciences Electronic Theses and Dissertations
This dissertation examines the incoming Pacific plate and the overriding forearc at the Mariana Subduction Zone using passive and active source seismology. The incoming plate, with water bound in the plate sediment, crust and mantle, is of interest to help constrain the global water cycle. The seismogenic zone at Mariana is noted for being an aseismic end-member, while extensional faults and active serpentine mud volcanoes characterize the forearc. I use an ocean bottom seismograph (OBS) deployment spanning both the incoming Pacific Plate and the forearc to study the seismicity and shallow structure. The passive source component of the deployment consists …
Protean Caves And Cyrenean Grottos: The Subterranean World Of Vergil's Fourth Georgic, Kirby Schoephoerster
Protean Caves And Cyrenean Grottos: The Subterranean World Of Vergil's Fourth Georgic, Kirby Schoephoerster
Arts & Sciences Electronic Theses and Dissertations
Using the studies and methodologies spearheaded by the burgeoning field of geomythology, this project aims to reevaluate one of the most famous works of ancient literature, the Georgics of Vergil, within the context of karst geology. In other words, I plan to critically investigate the famous myth of Aristaeus using a geomythological lens that focuses on how Vergil treats caves and cave systems as related to (his) myth. The didactic poem as a whole, and much less so the myth of Aristaeus, has been assessed relatively little by archaeologists, and by geomythologists not at all. Yet, book four contains an …
Investigation And Classification Of Planetary Materials And Surfaces Using Novel Methods To Analyze Large Compositional Datasets: Quantitative X-Ray Compositional Mapping And Lunar Reconnaissance Orbiter Narrow Angle Camera Photometric Analysis, Timothy Michael Hahn
Arts & Sciences Electronic Theses and Dissertations
Our understanding of planetary bodies and their surfaces originates from measurements made by spacecraft instruments and laboratory analysis of extraterrestrial materials. Integration of these datasets can significantly advance the fields of planetary geology and geochemistry. The goal of my dissertation research has been to develop novel methods for interrogating extraterrestrial samples and planetary regoliths, with an emphasis on integrating these complementary datasets. Additionally, my research has focused on utilizing ‘big data’ within the geoscience and planetary science communities, whether that data be geospatial or geochemical in nature. My dissertation research involves two separate, but related projects: (1) coupling Apollo 17 …
Local Environmental Controls On Sulfur Isotope Ratios In Marine Sedimentary Iron Sulfide Minerals, Roger Nicholas Bryant
Local Environmental Controls On Sulfur Isotope Ratios In Marine Sedimentary Iron Sulfide Minerals, Roger Nicholas Bryant
Arts & Sciences Electronic Theses and Dissertations
The controls on the bulk sulfur isotopic composition of marine sedimentary iron sulfides (often referred to simply as pyrite; δ34Spyr) are poorly understood. Nevertheless, many have employed δ34Spyr in efforts to reconstruct the past operation of the biogeochemical sulfur cycle, from the planetary scale down to individual microbial metabolisms. This practice has been thrown into doubt by a growing body of evidence that suggests δ34Spyr is strongly controlled by local environmental conditions. This dissertation describes efforts to determine the mechanisms responsible for the link between local environmental conditions and δ34Spyr. In order to do this, we developed novel laboratory procedures …
Fundamental Controls On The Reactivity Of Aluminum Oxide And Hydroxide Surfaces: Contributions Of Surface Site Coordination States And Interfacial Water Structure, Tingying Xu
Arts & Sciences Electronic Theses and Dissertations
Chemical reactions at mineral-water interfaces are of great importance in many geological and environmental processes. Essential to many of these is adsorption because it directly controls contaminant fate and nutrient availability, promotes the nucleation and growth of minerals, initiates surface redox reactions, and plays a crucial role in carbon cycling and sequestration. These reactions occur at mineral surface sites having multiple possible coordination states that interact with both adsorbates and water. While general ion adsorption mechanisms and surface charging behaviors are well established, the roles of individual surface functional group types and water in affecting the structure and reactivity of …
Spectral And Stratigraphic Mapping Of Layered Sulfate Deposits On Mars Using Advanced Crism Data Processing Techniques, Kathryn Elizabeth Powell
Spectral And Stratigraphic Mapping Of Layered Sulfate Deposits On Mars Using Advanced Crism Data Processing Techniques, Kathryn Elizabeth Powell
Arts & Sciences Electronic Theses and Dissertations
We apply orbital remote sensing of Mars to analyze the mineralogy and geologic setting of two areas near rover landing sites. We use the Compact Reconnaissance Orbiter for Mars (CRISM) observations, modeled to single scattering albedo, to identify and map hydrated sulfates in layered sedimentary sequences in these two locations. In Meridiani Planum, the Opportunity rover has characterized a ~10 m section of sulfate-bearing deposits known as the Burns formation. At our study area in ~20 km to the south at Iazu Crater, we found that the crater walls have strong spectral signatures of polyhydrated sulfate, strongly correlated with a …
Effects Of Regolith Properties On Uv/Vis Spectra And Implications For Lunar Remote Sensing, Ecaterina Ioana Coman
Effects Of Regolith Properties On Uv/Vis Spectra And Implications For Lunar Remote Sensing, Ecaterina Ioana Coman
Arts & Sciences Electronic Theses and Dissertations
Lunar regolith chemistry, mineralogy, various maturation factors, and grain size dominate the reflectance of the lunar surface at ultraviolet (UV) to visible (VIS) wavelengths. These regolith properties leave unique fingerprints on reflectance spectra in the form of varied spectral shapes, reflectance intensity values, and absorption bands. With the addition of returned lunar soils from the Apollo and Luna missions as ground truth, these spectral fingerprints can be used to derive maps of global lunar chemistry or mineralogy to analyze the range of basalt types on the Moon, their spatial distribution, and source regions for clues to lunar formation history and …
The Evolution Of Igneous Rocks On The Moon: Insights From Lunar Meteorites And Apollo 12, Sarah Valencia
The Evolution Of Igneous Rocks On The Moon: Insights From Lunar Meteorites And Apollo 12, Sarah Valencia
Arts & Sciences Electronic Theses and Dissertations
Lunar samples are the “ground truth” that anchor our knowledge of lunar geology. Lunar rocks present many challenges in that they are often brecciated (composed of multiple rock types), and their location of formation on the Moon is not always known. The brecciated nature of lunar samples also has advantages – multiple lithologies that have a related petrogenetic history can occur in the same sample, allowing us to trace the petrogenetic history of evolving magmatic systems. In this dissertation, I examine two evolved magmatic systems, using samples from the Northwest Africa (NWA) 773 clan of lunar meteorites and Apollo 12 …
Seismic Array Studies Of Antarctica And Madagascar, Martin James Pratt
Seismic Array Studies Of Antarctica And Madagascar, Martin James Pratt
Arts & Sciences Electronic Theses and Dissertations
The scope of this dissertation is broad, involving seismic array studies from Antarctica and Madagascar, and includes aspects of glaciology and oceanography as well as solid Earth geophysics. Chapter 2 focuses on the study of stickslip motion of the Whillans Ice Stream, West Antarctica. It includes methods combining seismic array and GPS time series, from ice stream based-sensors, to determine source dynamics in the framework of an earthquake source. The source characteristics are then analyzed to explain far-field seismic observations of ice stream- sourced surface waves detected throughout West Antarctica. Locations of asperities, or sticky- spots, that cause the Whillans …