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Full-Text Articles in Earth Sciences

Hydrogeology Of The Little River Animal Agriculture Environmental Research Unit And Impacts Of Dairy Operations On Groundwater, Robert Wesley Hunter Dec 2013

Hydrogeology Of The Little River Animal Agriculture Environmental Research Unit And Impacts Of Dairy Operations On Groundwater, Robert Wesley Hunter

Masters Theses

This thesis describes the development of an integrated hydrogeologic/hydrologic site assessment and groundwater/surface water quality monitoring program at the University of Tennessee – Little River Dairy Farm, located near Townsend, TN. Hydrologic/hydrogeologic investigations of streams and groundwater at the site have been underway for more than 5 years, and these are expected to provide background data for assessing impacts of dairy wastes. The lower half of the ~180 ha site consists of low-relief fields used for row crops, which are underlain by 4 – 9 m of alluvial deposits on top of black shale or limestone that include sinkhole features. …


Stratigraphic And Geochemical Investigation Of The Mesoproterozoic Atar And El Mreiti Groups, Mauritania: Insights Into Carbon Cycling And Ocean Redox Stratification In A Low Oxygen World, Geoffrey J. Gilleaudeau Aug 2013

Stratigraphic And Geochemical Investigation Of The Mesoproterozoic Atar And El Mreiti Groups, Mauritania: Insights Into Carbon Cycling And Ocean Redox Stratification In A Low Oxygen World, Geoffrey J. Gilleaudeau

Doctoral Dissertations

The protracted oxygenation of Earth’s surface environments played a critical role in biospheric evolution during the Proterozoic eon. Initial oxygenation began ~2.3 Ga during the Great Oxidation Event, yet Earth’s oceans did not become fully oxygenated until at least the end of the Neoproterozoic—coincident with the first appearance of metazoans in the fossil record. Patterns of environmental change and evolutionary innovation are more complex and less certain, however, in the prolonged period between these two oxygenation thresholds. The late Mesoproterozoic (1.3 to 1.0 Ga) was marked by increasing biospheric oxygen—evidenced by increased carbon isotopic variability and an increase in marine …


Genetic Analysis Of Bacterial Gene Variations In Sulfidic Springs And The Influence On Geochemistry, Brendan Joseph Headd Aug 2013

Genetic Analysis Of Bacterial Gene Variations In Sulfidic Springs And The Influence On Geochemistry, Brendan Joseph Headd

Doctoral Dissertations

Culture-independent methods have revolutionized environmental microbiology and geomicrobiology studies and next-generation sequencing and metagenomics techniques continue to reveal the vast genetic diversity of microorganisms. But, these approaches provide comparatively little quantitative information about the roles that naturally occurring microbial gene variations play in local biogeochemical cycling. The goal of this study was to identify how the physical distribution and genetic diversity of microbial genes within a habitat impact environmental geochemistry by examining the biogeography of 16S rRNA genes and bacterial sulfur oxidation (Sox) genes in terrestrial sulfidic springs. 16S rRNA gene pyrosequences were obtained from microbial mats inhabiting eight sulfidic …


Adsorption Of Antimony By Birnessite And The Impact Of Antimony On The Electrostatic Surface Properties Of Variable-Charge Soil Minerals, Kalyn Alaine Vergeer May 2013

Adsorption Of Antimony By Birnessite And The Impact Of Antimony On The Electrostatic Surface Properties Of Variable-Charge Soil Minerals, Kalyn Alaine Vergeer

Masters Theses

Antimony (Sb) is a toxin that can be found in high concentrations in the soil due to anthropogenic sources. Antimony exists in soil as Sb(V) in the monovalent antimonate hydroxyanion. The adsorption mechanisms of Sb(V) are not well-characterized. The objective of this study was to further elucidate Sb(V) adsorption mechanisms by examining the impact of adsorption on surface charging characteristics of gibbsite, goethite, birnessite, and kaolinite. Also examined was Sb(V), SO4 [sulfate], and PO4 [phosphate] adsorption by birnessite. Electrophoretic mobility and potentiometric titrations were employed to examine the ζ-potential [zeta-potential] and net proton surface charge density as a …


Metamorphic Phase Equilibria In A Contact Aureole: Tres Hermanas Mountains, Luna County, New Mexico., Carissa Dawn Snyder May 2013

Metamorphic Phase Equilibria In A Contact Aureole: Tres Hermanas Mountains, Luna County, New Mexico., Carissa Dawn Snyder

Masters Theses

To characterize the metamorphism in the Tres Hermanas Mountains contact–metamorphic aureole in Luna County, New Mexico, I mapped and collected samples of the Paleozoic strata near the quartz monzonite pluton along the northeast flank of North Peak. Stratigraphy in this area includes the Pennsylvanian undivided unit that is composed of thin-medium interbedded limestone, shale, and sandstone and the Hueco Formation that could be broken out into four members: a pebble–cobble conglomerate marks the base, a medium to massive bedded siliceous limestone is next, followed by a pure limestone member and topped by a breccia bed in places marking the fault …