Digital Commons Network^™

Numerical And Experimental Constraints On Trace Element Fractionation During Lunar Magma Ocean Solidification, Dian Ji

Masters Theses

Traditional lunar magma ocean (LMO) theory suggests the anorthositic lunar crust formed by floating of buoyant plagioclase, one of the major products of LMO solidification, on the surface of LMO. To test this model, after applying experimentally determined LMO solidification sequences, we compared calculated Rare Earth Element (REE) concentrations of lunar plagioclase to plagioclase in Apollo ferroan anorthosites and lunar anorthositic meteorites. Several initial LMO compositions, and lunar-relevant mineral-melt partition coefficient predictive models were tested (where the partition coefficient is the concentration ratio of a specific element between two phases). Compared with plagioclase in the natural samples, modeled plagioclase directly …

Evaluating Bulk Carbon And Nitrogen Isotope Compositions Of Acidic Hydrothermal Sediments On Earth– Implications For Mars Astrobiology, Chance Sturrup

Masters Theses

Carbon isotopes have been widely used as unique biosignatures because biologic processes commonly result in distinctive negative delta ¹³C values (-35 to -10 ‰) within organic material on Earth. However, the bulk delta ¹³C analysis in Gale crater sediments on Mars revealed a wider range of values, from -25 to +56 ‰ (Franz et al., 2020), which suggests a more complex origin. To determine if bulk isotope analysis can be successfully used to detect a microbial signature in a martian analog environment, we analyzed concentrations and isotope compositions of C within hydrothermal sediments in Iceland (Námafjall, Krýsuvík, Hveragerdi) …

Comparative Geochemical Analysis Of Recent Volcanic Flows On Barva Volcano, Costa Rica, Julie Coulombe

Masters Theses

ABSTRACT

Barva Volcano is a dormant stratovolcano in the Cordillera Central region of Costa Rica, rising above the capital city of San Jose with a population of 347,000. Barva’s recent inactivity and extensive forestation have resulted in fewer investigations of its composition, petrogenesis, and eruptive history. The objective of this research is to analyze the geochemical data from several of the most recent lava flows, evaluate variability between eruptive units, and ascertain physical conditions within the Barva magma storage region. The data collected in this study helps constrain the geochemistry of units seen in the quarry and provides information regarding …

Understanding Hydrogen Variations In Silicate Glasses As A Result Of Degassing: Fire-Fountaining On The Moon And Earth, Erin M. Recchuiti

Masters Theses

Volatiles, particularly hydrogen, play a key role in volcanic eruptions, especially explosive eruptions like fire-fountaining [e.g., Saal et al. 2002; Dixon 1997; Arndt & von Engelhardt 1987; Yoder 1976]. Discerning volatile abundance and behavior during ascent and eruption can aid in understanding the source melt and primary volatile content of planetary interiors. Volcanic glasses are samples closest to the primary melt, as they quench quickly enough to limit fractionation or crystallization. This is paramount for volatile studies, especially pertaining to water as its constituents are oxygen and hydrogen. Hydrogen is the most volatile element and one of the first to …

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 …

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 …

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. …

Carbon Metabolism In Cave Subaerial Biofilms, Victoria E. Frazier

Masters Theses

Subaerial biofilms (SABs) grow at the interface between the atmosphere and rock surfaces in terrestrial and subterranean environments around the world. Multi-colored SABs colonizing relatively dry and nutrient-limited cave surfaces are known to contain microbes putatively involved in chemolithoautotrophic processes using inorganic carbon like carbon dioxide (CO₂) or methane (CH₄). However, the importance of CO₂ and CH₄ to SAB biomass production has not been quantified, the environmental conditions influencing biomass production and diversity have not been thoroughly evaluated, and stable carbon and nitrogen isotope compositions have yet to be determined from epigenic cave SABs. …

Electron Microprobe In Situ Monazite Dating Of The Slide Lake Shear Zone, Jeremy Leierzapf

Masters Theses

The Colorado mineral belt (CMB) shear zone system records Proterozoic deformation episodes documenting the progressive tectonic accretion of Laurentia. Regional fold formation (D₁ & D₂) is coeval with the ca. 1700 – 1600 Ma Yavapai and Mazatzal orogenies, while Mesoproterozoic sub-vertical shear zones (D₃ & D₄) are a response to 1450 – 1300 Ma intracontinental deformation. The Slide Lake shear zone (SLSZ) is a sub-horizontal shear zone located in the Northern Sawatch Range, central Colorado. Aside from its orientation, the SLSZ records similar deformational structures to other shear zones in the CMB, but there …

Experimental Study Of The Alteration Of Basalt On The Surface Of Venus, Hannah Teffeteller

Masters Theses

Venus is the second planet from the sun, distinguished by its thick atmosphere which prevents visible observations of the surface. Our understanding of its surface is therefore dominated by surface interactions with electromagnetic radiation (e.g. radar, visible-to-infrared, and X-ray wavelengths) which have been collected by a series of missions including the Soviet’s Venera missions, the National Aeronautics and Space Administration’s (NASA) Magellan mission, and the European Space Agency’s (ESA) Venus Express orbiter (Barsukov et al. 1982; Head et al. 1992; Smrekar et al. 2010). The atmosphere of Venus is composed almost entirely (~97%) of CO2 gas with trace amounts of …

Determining Sources Of Nitrate In The Semi-Arid Rio Grande Using Nitrogen And Oxygen Isotopes, Diego Alberto Sanchez Hernandez

Masters Theses

The Rio Grande, a semi-arid river in the American Southwest, is a major source of surface water for agriculture and drinking supplies in New Mexico and Texas. In addition to increasing salinity, considerable increases of NO₃^- [nitrate] have been observed in the semi-arid portion of the Rio Grande. It is possible that elevated water salinity inhibits denitrification on irrigated fields and, thus, fails to mediate excess nutrient load from anthropogenic activities. Therefore, two major goals of this project were to 1) characterize and quantify major NO₃^- sources, and 2) assess whether elevated water salinity affects microbial …

A Textural Image Analysis Study Of Mars-Analog Sediment: Comparisons Of 2d And 3d Textural Analysis Methods, Image Resolution, And The Effects Of Shadows, Mary Agnes Eibl

Masters Theses

Sediments from Mars-analog, basaltic, aeolian (Moses Lake dunes, WA) and fluvial (Death Valley region, CA) environments were analyzed for textural properties (grain size, roundness, sphericity) to understand how well image-based analyses compare with actual sediment characteristics. Three interrelated studies determined: (1) how well high-resolution, two-dimensional (2D) image analysis compares with three-dimensional (3D) sediment textures, (2) the extent to which decreasing image resolution affects textural analyses by comparison with high-resolution images, and (3) the extent to which shadows at different incident solar angles has on textural measurements. In both aeolian and fluvial environments, 2D grain-size distributions and statistics closely match 3D …

Role Of Sorting On The Composition Of Siliciclastic Sediment: Implications For Interpreting Provenance After Limited Transport In An Arid Climate, Forrest Christopher Driscoll

Masters Theses

This study tested whether transport distances (< 500 m) have the capacity to shape the geochemistry of sediments across multiple grain-size populations due to sorting derived from a single source. In the Stepladder Mountains, Mojave Desert, CA, a < 1 km² [square kilometers] watershed allows for a controlled study to understand how modern sediments acquire their composition from a single granodioritic source in an arid climate where there is no chemical weathering. Sediments are naturally sorted into distinct grain-size populations, with modes ranging from very fine sand to gravel within a single, alluvial channel. Sediment samples representative of each population were petrographically and geochemically analyzed in order to test the effectiveness of commonly used discrimination diagrams. Sediments became proportionally enriched in plagioclase and biotite and depleted in K-feldspar and quartz with decreasing grain …

Petrology Of The Paired Dominion Range 2010 Howardites: Indications Of Magmatic Complexity On Asteroid Vesta, Timothy Michael Hahn Jr.

Masters Theses

A comprehensive petrologic and geochemical characterization of six paired howardites collected from the Dominion Range, Antarctica was conducted. These howardites are megaregolith samples from the asteroid 4 Vesta. Collectively, they contain an assortment of igneous rock fragments that indicate magmatic processes were capable of producing a variety of rock types; 22 chemically and texturally discrete basaltic eucrite, cumulate eucrite, and diogenite lithologies are recognized. The implications for remote-sensing observations of Vesta are discussed. The petrogenesis of two previously unrecognized lithologies are described in further detail: an evolved dacite that we propose is a residual melt from extensive crystallization, and a …

Late Tertiary Tectonic Uplift In The Southern And Central Appalachians, Mary Sheela Biswal

Masters Theses

The exposed Appalachian Mountains extend about 2500 km from Newfoundland to Alabama with the highest peaks >2000 m above sea level. The last orogeny that affected Appalachian crust was the 325-260 Ma Alleghanian. Even with minimal erosion rates, it is highly unlikely that the Appalachians could have sustained such elevations for over 200 m.y., suggesting that recent tectonic uplift has produced today’s mountainous topography. The multiple phases of Tertiary uplift are related to poorly understood processes, but a large amount of data from today’s mountain chain and the adjacent Coastal Plain indicate the present high topography is anomalous and clearly …

Experimental Limestone Dissolution And Changes In Multiscale Structure Using Small- And Ultra Small- Angle Neutron Scattering, Chad Alan Novack

Masters Theses

Small angle neutron scattering (SANS), ultra-small angle neutron scattering (USANS), and backscatter electron (BSE) imaging, along with neutron computed tomography (NCT) were used in this study to experimentally quantify pore size, distribution, and connectivity of dissolved limestone geometries. Eight samples of Indiana limestone of two different initial permeabilities (2-4 mD and 70 mD ) [millidarcy] were reacted with HCl [hydrochloric acid] solutions at differing pH (2 and 4), and flow rates (0.1 and 10 cm³/min) [cubic centimeters per minute] to describe a broad range of parameters that affect limestone dissolution. NCT was first used to image the dissolution …

Survival And Growth Rate Of Translocated Freshwater Mussels Lampsilis Fasciola And Medionidus Conradicus, Laura L. Pullum

Masters Theses

Freshwater mussels (Family Unionidae and Margaritiferidae) are a widely threatened group of bivalve molluscs, particularly in the Southeastern United States. Translocation of freshwater mussels is an increasingly common conservation method. However, there are relatively few studies that quantitatively investigate the factors influencing translocation success or failure. In October 2013, hundreds of Medionidus conradicus and Lampsilis fasciola were translocated to the Pigeon and Nolichucky Rivers in Tennessee, with an interim partial survey (June 2014) and a full survey (October 2014). In this study, I analyze this field-collected data to determine the mechanism(s) that currently influence the outcomes of Tennessee mussel translocation. …

Europan Double Ridge Morphology As A Test For Hypothesized Models Of Formation, Ashley Caroline Dameron

Masters Theses

Double ridges on the Jovian satellite Europa consist of two ridges with a central trough. Several hypotheses exist describing their formation. Explosive cryovolcanism would result in granular ice depositing as two self-symmetric ridges flanking a central fracture, lying at or below the angle of repose (AOR). Cryo-sediments deposited by tidal squeezing and low-viscosity cryolavas emplaced by effusive cryovolcanism would likely have shallow slopes, although ridge symmetry is not expected. A second group of hypotheses involves brittle deformation of the crust, namely by diapirism, shear heating, and buckling of the lithosphere due to compression. Because these models involve uplifting vertical fractures, …

Geostatistical Analysis Of Point Soil Water Retention Parameters For Flint Sand, William Blake Roberts

Masters Theses

Geostatistics were employed to characterize sub-core scale heterogeneity and identify spatial structure in previously published water retention data (Kang et al., 2014) obtained using neutron radiography for Flint sand. The water retention data were parameterized using the Brooks and Corey (BC) model. The BC parameters investigated were: saturated water content (Ѳ_s), residual water content (Ѳ_r), air entry value (ψ_a), and pore size distribution index (λ). Spatial dependency in the BC parameters was identified using semivariograms. Of the four BC parameters analyzed, two were found to be spatially correlated, Ѳ …

Measurement Of Hysteretic Shale Capillary Pressure – Saturation Relationships Using A Water Activity Meter, Brendan Michael Donnelly

Masters Theses

Capillary pressure is the pressure difference across the interface of two immiscible fluids within a porous medium due to the interfacial tension between fluids and is related to both the properties of the fluids and the porous medium. Capillary pressure within a porous medium will change depending upon its degree of saturation. Understanding the relationship between capillary pressure and saturation for a rock allows for the modeling of multi-phase flow. Many traditional methods of measuring capillary pressure are unsuitable for the characterization of shale due to their inability to measure the high capillary pressures found within the small pores. Furthermore, …

Establishing A Chronology Of Late Quaternary Glacial Advances In The Cordillera De Talamanca, Costa Rica, Rebecca Susan Potter

Masters Theses

Little research has focused on glacial events in the tropics. Providing an absolute glacial chronology in Costa Rica will build a foundation for future glacial chronologies and paleoclimate reconstructions in the highlands of Central America. Evidence of past glaciation, including moraines and glacial lakes, is preserved within formerly glaciated valleys in the Cordillera de Talamanca. Orvis and Horn (2000) constrained deglaciation ages of the most recent glacial event in the Cordillera de Talamanca based on radiocarbon dates of glacial lake sediments. Radiocarbon ages indicated complete deglaciation after 12.4 ka cal BP but before 9.7 ka cal BP (Orvis and Horn, …

Characterizing Groundwater Ch4 And 222rn In Relation To Hydraulic Fracturing And Other Environmental Processes In Letcher County, Ky, St. Thomas Majeau Ledoux

Masters Theses

Hydraulic fracturing of shale deposits has greatly increased the productivity of the natural gas industry by allowing it to exploit previously inaccessible reservoirs. However, previous research has demonstrated that this practice can contaminate shallow aquifers with CH₄ [methane] from deeper formations. This study compares concentrations and isotope compositions of CH₄ sampled from domestic groundwater wells in Letcher County, Kentucky in order to characterize its occurrence and origins in relation to neighboring hydraulically fractured natural gas wells. Additionally, this study tests the reliability of ²²²Rn [radon] as an alternative tracer to CH₄ in identifying processes of gas …

Metamorphic Evolution Of Eastern Blue Ridge Calc-Silicates In Southwestern North Carolina, Northeastern Georgia, And Northwestern South Carolina, Gina Brianne Smith

Masters Theses

Calc-silicate rocks in the eastern Blue Ridge of SW North Carolina, NE Georgia, and NW South Carolina are products of contact and regional metamorphism. Two types of calc-silicates occur in this area: Type A rocks occur as contact metamorphosed xenoliths in the ~336 Ma Rabun Granodiorite batholith, and Type B rocks occur as mappable thin, elongate, ribbon-like units in the Tallulah Falls Formation east of the Rabun batholith. Petrographic and geochemical data confirm similar composition for both types and mineral assemblages that includes amphibole, garnet, epidote, diopside, quartz, and plagioclase with accessory zircon, sphene, and opaque minerals. Calcite, however, is …

Transport Of Fecal Pollution Indicators: Impacts From The Land Spreading Of Liquid Manure On Water Quality, Derek Lee Street

Masters Theses

This thesis is a case study to determine if groundwater and/or drainage tiles are important pathways for fecal migration to streams resulting from the application of liquid manure to cropland at a small dairy farm, the Little River Animal and Environmental Unit, near Townsend, TN. Traditional biological indicators, coliforms and E.coli, were used in conjunction with a bovine specific Bacteroides assay to measure fecal microbes. Total nitrates, turbidity, and other chemical parameters for water quality also were used to identify related fecal contamination. This thesis covers three separate manure applications. The first manure application occurred in May 2013, the …

Structural And Metamorphic Evolution Of The Haimanta Group: Insights From P-T-T-D Path Modeling Of Rocks Near The Leo Pargil Dome, Nw India, Kyle Vincent White

Masters Theses

The metasedimentary rocks of the Haimanta Group in the upper Sutlej Valley, NW India, record an extensive history of Himalayan deformation and metamorphism. Situated beneath the low-grade metasediments of the Tethyan Sedimentary sequence in the hanging wall of the South Tibetan detachment system (STDS), these poly-deformed rocks record Eocene–Oligocene burial metamorphism, crustal thickening and shortening, decompression and mid-crustal melting in the early Miocene, and exhumation along extensional shear zones related to the orogen-parallel exhumation of the Leo Pargil dome (LPD). Low-pressure assemblages (cordierite + sillimanite + quartz) overgrow Barrovian porphyroblasts in Haimanta Group rocks in the NE portion of Sutlej …

Calcitized Evaporites In The Precambrian: Deposition And Diagenesis In A Low Sulfate Ocean, Ashley René Manning Berg

Masters Theses

One of the most profound byproducts of the Great Oxidation Event (GOE) was the onset of oxidative weathering on land and the riverine delivery of sulfate to marine systems. The marine sulfur system therefore plays a critical role in reconstructing the oxygenation of the early Earth. Although the exact nature of marine oxygenation in aftermath of GOE remains uncertain, examination and modeling of marine sulfate suggest that sulfate concentrations remained below 2 millimolar (mM) until at least the middle Mesoproterozoic, and may have only reached about 10 mM in the latest Neoproterozoic. Such a low concentration of marine sulfate had …

Characterizing The Relationship Of Part Of The Inner Piedmont And Pine Mountain Window, Georgia, From Detailed Geologic Mapping, Geochemistry, Geochronology, And Structural Analysis At The Southwestern End Of The Cat Square Terrane, Justin Randolph Rehrer

Masters Theses

Geologic investigations at the southwestern end of the Cat Square terrane (CSt) in central Georgia provided new insight into the complex tectonic history of the Pine Mountain window (PMw) and neighboring Inner Piedmont terranes. Detailed 1:24,000-scale geologic mapping of an approximately 180 km2 area near Barnesville, Georgia has provided the foundation for further geochemical, geochronologic, and structural analyses refining models for tectonic development and emplacement of the CSt and PMw.

Whole-rock geochemical analyses of several CSt amphibolites yielded data suggesting a continental back-arc setting for genesis of the Cat Square basin (CSb). Major element data confirm derivation from a basaltic …

Crystallization Kinetics Of Olivine-Phyric Shergottites, Megan Elizabeth Ennis

Masters Theses

Petrographic and geochemical techniques applied to Martian meteorites can reveal their petrogenesis, and ultimately the magmatic evolution and thermal history of Mars. Two quantitative textural tools, crystal size distribution (CSD) and spatial distribution pattern (SDP) analysis, are utilized to describe the early crystallizing phases, olivine and pyroxene, of one olivine-phyric shergottite (EET 79001A, DaG 476, and Dho 019) from each sampling locality as inferred from Mars ejection ages. Qualitative observations of trace element zonation patterns (P, Cr, and Al) in olivine are used in conjunction with CSD and SDP to characterize the crystallization history of these samples. Previously reported CSDs …

Structural Analysis Of The Tablerock Thrust Sheet, Grandfather Mountain Window, Northwestern North Carolina: Emplacement Kinematics Of A Large Horse In A Major Thrust System, Ann Elizabeth Walker

Masters Theses

The Tablerock thrust sheet is exposed along the southwestern margin of Grandfather Mountain window in northwestern North Carolina, where it separates basement and cover rocks inside the window from basement thrust sheets of the overriding Blue Ridge-Piedmont megathrust sheet. It is a complex of footwall-derived horses of rifted-margin metasedimentary rocks, including Neoproterozoic to Early Cambrian Chilhowee Group quartzite and phyllite, and Shady Dolomite. Penetrative deformation throughout the Tablerock thrust sheet is defined by an extensively transposed foliation, and strong colinearity between well developed transport lineations and SE/NW-trending tight, isoclinal, and sheath folds. Centimeter- to meter-scale sheath folds are common throughout …

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. …