Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

Vorticity And Kinematic Analysis Of The Cordillera Blanca Shear Zone, Peru, Corey Flynn Dec 2021

Vorticity And Kinematic Analysis Of The Cordillera Blanca Shear Zone, Peru, Corey Flynn

Masters Theses

Quantitative vorticity analyses applied to naturally deformed rocks are essential for studying kinematics in shear zones and can be performed using a range of methods, which have been developed over the last two decades. An understanding of vorticity, or the contribution of pure vs. simple shear, can permit for the modeling of shear zone development in a deformed region. Recent (5 Ma-present) deformation in the Cordillera Blanca Shear Zone of the Peruvian Andes has exposed sections of the middle crust at the surface, allowing for observation and analysis of shear zone processes. Oblique grain-shape (OGS) analysis and crystallographic vorticity analysis …


Influence Of Physical Variability Of Highly Weathered Sedimentary Rock On Nitrate In Area 3 Of The Enigma Field Research Site At Y-12, Erin Kelly Dec 2021

Influence Of Physical Variability Of Highly Weathered Sedimentary Rock On Nitrate In Area 3 Of The Enigma Field Research Site At Y-12, Erin Kelly

Masters Theses

Uranium processing and waste storage in unlined waste ponds leached contaminants into the groundwater at Y-12, Oak Ridge, Tennessee, from the 1950s to 1980s. Groundwater wells near the S-3 ponds have had the highest nitrate concentrations of groundwater anywhere in the world (>10,000 mg/L). For reference, the maximum contaminant level for nitrate in drinking water set by the U.S. Environmental Protection Agency is 10 mg/L. Since 2012, the ENIGMA (Ecosystems and Networks Integrated with Genes and Molecular Assemblies) group has been characterizing, monitoring, and conducting field experiments to understand the interactions between contaminants, microbes, and the subsurface. The goals …


Impact Of Calcium Carbonate Reactant Size And Mineralogy On Dolomite Stoichiometry, Katharine G. Rose Aug 2021

Impact Of Calcium Carbonate Reactant Size And Mineralogy On Dolomite Stoichiometry, Katharine G. Rose

Masters Theses

Dolomite is a common, diagenetic, Mg-Ca carbonate mineral. Dolomitization occurs by a dissolution-precipitation reaction between a CaCO3 precursor (calcite or aragonite) and Mg bearing fluids. The amount of Mg in dolomite, referred to as dolomite stoichiometry (mol% MgCO3), varies in natural dolomites (38-50 mol% MgCO3). Laboratory experiments have shown that dolomite stoichiometry is dependent on physiochemical factors of the diagenetic fluids (i.e., temperature, salinity, and Mg/Ca). The impact of the CaCO3 precursor on stoichiometry, however, has not been studied directly. This study tests how the CaCO3 precursor size (sieve size) and mineralogy (calcite …


Experimental Alteration Of Venusian Surface Basalts In A Hybrid Co2-So2 Atmosphere, Robert B. Reid Aug 2021

Experimental Alteration Of Venusian Surface Basalts In A Hybrid Co2-So2 Atmosphere, Robert B. Reid

Masters Theses

Venus’ surface and interior dynamics remain largely unconstrained, due in great part to the major obstacles imposed by its 470°C, 90 bars surface conditions and its thick, opaque atmosphere. Orbiter-based thermal emission data provide an opportunity to characterize the Venus surface. However, interpretations of such spectra critically depend on understanding interactions between the planet’s surface basaltic rocks and its caustic, SO2-bearing CO2 atmosphere. Several studies, using remote sensing, thermodynamic modeling, and laboratory experiments have placed constraints on alteration mineralogies and rates. Yet constraint with respect to SO2-mediated reactions with basalts of contrasting compositions remains incomplete. …


Preclassic Cultural Eutrophication Of Lake Petén Itzá, Lowland Guatemala, By The Early Maya Of Nixtun-Ch'ich', Brooke A. Birkett Jan 2021

Preclassic Cultural Eutrophication Of Lake Petén Itzá, Lowland Guatemala, By The Early Maya Of Nixtun-Ch'ich', Brooke A. Birkett

Masters Theses

"Paleolimnological evidence indicates the ancient Maya transformed lowland terrestrial ecosystems by felling forest vegetation to construct large civic-ceremonial centers and expand agriculture. The effects of prehistoric Maya land alterations on lake trophic status, however, remain poorly understood. We analyzed a 515-cm-long sediment core from Lake Petén Itzá, lowland Guatemala, to infer paleoenvironmental changes resulting from Maya occupation of the riparian archaeological site of Nixtun-Ch'ich'. Substantial increases in charcoal and fecal stanol concentrations indicate Maya occupation of the Candelaria Peninsula by the late Early Preclassic period beginning ca. 1400 cal yr Before the Common Era (hereafter BCE), despite scant archaeological evidence …


Multiple Generations Of Phlogopite In An Alnöite Diatreme: Insights Into The Petrogenesis Of The Avon Alkaline Igneous Province, Missouri, Nathan Gregory Limbaugh Jan 2021

Multiple Generations Of Phlogopite In An Alnöite Diatreme: Insights Into The Petrogenesis Of The Avon Alkaline Igneous Province, Missouri, Nathan Gregory Limbaugh

Masters Theses

“Alkaline Ultramafic Carbonatite (AUC) complexes, although rare, are valued for diamonds and REEs, and as windows into subcontinental and mantle processes as recorded by rock fabrics, mineral spatial relationships, and mineral compositions. We report specifically on olivine and phlogopite petrographic relationships and compositions from the Devonian alnoite diatreme-facies of the Avon Alkaline Igneous Province, Missouri. The diatreme alnoite is a mixture of domains of olivine magmaclasts (OM) set in a crystal-rich melilite matrix. OM are highly fractured, serpentinized olivine pseudomorphs with variable amounts of pristine olivine fragments. Larger olivine domains typically exhibit clear crystal faces and irregular “channels” indicative of …


Relationships Among Mineralogy, Geochemistry, And Oil And Gas Production In The Tuscaloosa Marine Shale, Hayley Roxana Beitel Jan 2021

Relationships Among Mineralogy, Geochemistry, And Oil And Gas Production In The Tuscaloosa Marine Shale, Hayley Roxana Beitel

Masters Theses

"The Tuscaloosa Marine Shale (TMS) is an unconventional shale reservoir located in southeast Louisiana and southwest Mississippi. Limited mineralogical and geochemical data for the TMS have been published. The data that do exist indicate that the formation is heterogeneous. Consequently, previous investigators and oil and gas companies have not managed to effectively link mineralogical and chemical changes to oil and gas production in the TMS. These linkages are critical to establish for future exploration efforts. In this study, we attempt to establish these relationships by gathering all existing mineralogical and chemical data in the TMS, including newly acquired data from …