Master of Science (MS), Ohio University, 2024, Geological Sciences

Dense non-aqueous phase liquids (DNAPLs) are a group of volatile organic compounds (VOCs) that are commonly used industrially and frequently escape confinement and reach the water table. DNAPLs are denser than water and thus sink until reaching a confining layer, at which point weak solubility leads to the formation of a dilute dissolved contaminant plume as groundwater flows by which can then pollute and threaten downstream wells and water supplies. Existing remediation methods for DNAPL plumes are generally unsatisfactory and not very effective while also requiring significant investment in time and labor. This study continues work on the slow-release permanganate gel (SRP-G) first proposed by Lee et al. (2013) and further developed by Gupta (2013), Hastings (2021), and Acheampong (2023) in a flow-tank setting and examines its effectiveness in remediating a dilute dissolved plume of trichloroethylene (TCE), a common DNAPL contaminant. A 200 ppb TCE solution was pumped through the flow tank and SRP-G was injected. MnO4 - release and spread was monitored in twelve wells at three depths and samples were collected from three locations for TCE analysis. A statistically significant negative correlation was found between MnO4 - in solution and TCE concentration. This demonstrates that the SRP-G was able to effectively remediate the TCE contaminant plume and reduce contaminant concentration to approximately half of background levels. Future studies are suggested examining SRP-G behavior and remediation potential in anisotropic heterogeneous media and in field settings.

Doctor of Philosophy, Case Western Reserve University, 2024, Geological Sciences

Little is understood about the chemical evolution of banded iron formations (BIFs) subducted into the mantle during the Precambrian era. In general, the mantle becomes more reducing with increasing depth, with much of the deep mantle thought to be below the iron-wustite (IW) buffer. At equilibrium, under shallower mantle conditions, the hematite and magnetite in subducted BIFs would reduce wustite. In more deeply subducted BIFs, where the oxygen fugacity buffer is below IW, the wustite would reduce to iron metal. A key question is how rapidly iron oxide reduction reactions proceed at mantle pressures and temperatures. Fast reaction rate would imply that large amounts of wustite and/or metal may have precipitated in the deep mantle. BIFs that reduced to wustite and resisted further reduction could exist in the form of ULVZs (ulta-low velocity zones), as suggested by Dobson and Brodholt (2005). BIFs that fully reduced to iron metal could have produced large volume iron diapirs which would have been capable of sinking into the core and providing an inner core nucleation substrate, as suggested by Huguet et al. (2018). The studies reported here seek to answer these questions by determining the high-pressure, high-temperature reduction rates of iron oxides under mantle conditions. Chapter one describes the various approaches used to recreate banded iron formation subduction at high-pressures and high temperatures. Experiments explore temperatures from 600-1200 oC and pressures from 1.5-15 GPa. Chapter two addresses the first step of BIF reduction—the reduction of hematite and magnetite to wustite in the upper mantle. Experiments explore 14 temperatures from 600-1400 oC and pressures between 2-14 GPa. Chapter three addresses the final step in BIF reduction—the reduction of wustite to iron metal in the lower mantle.

Master of Science (MS), Ohio University, 2024, Geological Sciences

This study investigates the extent, nature, and formation processes of Paleo Lake Buckeye during the Late Pleistocene, located in the Buckeye Creek watershed in the central Appalachian Mountains. This thesis integrates GIS mapping, field methods utilizing sediment coring and trenching, radiocarbon dating and grain size analysis to reconstruct the margins and depositional environments of Paleo Lake Buckeye and its surrounding landscape. Radiocarbon and optically stimulated luminescence (OSL) dating indicate that the lake formed between 20,000 and 40,000 years ago, coinciding with the peak of the last glacial epoch. The stratigraphic analysis shows fine-grained lacustrine deposits, organic rich layers, and episodic coarse-grained beds, which reflects periods of quiet water deposition interrupted by high-energy events. Paleo Lake Buckeye's formation is linked to periglacial conditions, where freeze thaw cycles mobilized sediments and permafrost dynamics influenced hydrological processes. This research not only interpret the paleoenvironmental conditions of the Buckeye Creek watershed during the Late Pleistocene, but also contributes to broader discussions on glacial and periglacial processes, climate variability, and landscape evolution in the central Appalachian Mountains.

Master of Science (MS), Ohio University, 2024, Geological Sciences

Blueschists are an important petrogenetic indicator of subduction and the first appearance of blueschists in the geologic record is commonly taken as evidence for the start of modern-style plate tectonics on Earth. The oldest known blueschists are Neoproterozoic in age, so studies of these blueschists may provide information about the processes and conditions associated with the initiation of plate tectonics on Earth. Of the known Neoproterozoic blueschist localities, the Anglesey (Wales, UK) blueschists are of particular importance because they contain the mineral lawsonite and are thought to be the oldest known lawsonite-bearing rocks in the geologic record. Petrographic, bulk-rock geochemical, and mineral composition and zoning data were acquired to better understand the protolith of the Anglesey blueschists, the conditions (P-T) under which they formed, and their metamorphic evolution. The bulk-rock major and trace element compositions of the metamafic rocks in the Anglesey blueschist belt are generally consistent with a mid-ocean ridge basalt (MORB) protolith, although some samples display variable enrichments in the large ion lithophile elements (LILEs; Cs, Ba, Rb), as well as Sr, Pb, and U. Incompatible trace element systematics suggest most samples underwent seafloor alteration prior to subduction. The most common amphiboles in the Anglesey blueschist belt are glaucophane, winchite, actinolite, riebeckite, and magnesio-riebeckite. Amphiboles in the blueschist facies rocks have core-to-rim zoning and record a transition from calcic/sodic-calcic amphiboles (winchite and/or actinolite cores) to sodic amphiboles (glaucophane rims). Riebeckite and magnesio-riebeckite are most common in greenschist and transitional greenschist-blueschist facies rocks, where they display patchy zoning and compositional variations in Fe3+ and Al. Differences between the amphiboles developed in the greenschist and blueschist facies rocks likely reflect variations in the pressure- (open full item for complete abstract)

Master of Science (MS), Wright State University, 2024, Earth and Environmental Sciences

The Teays River Valley is an ancient river valley system that existed before the Pleistocene Ice Age and spanned present-day Illinois, Indiana, Ohio, West Virginia, and Virginia. During the Pleistocene Ice Age, the Teays River Valley was buried by advancing continental glaciers and meltwater throughout most of its length. Due to the Teays' average width of roughly 2 miles and burial depth of approximately 200 meters (656 feet), the Ohio Geological Survey has been pursuing geophysical methods to map the location and depth of the Teays River Valley in Ohio. The present study is a refraction analysis using the first breaks from a seismic reflection dataset from west-central Ohio across the potential location of the buried Teays Valley. The seismic refraction results display a bedrock topography similar to the original seismic reflection profile, having an estimated bedrock depth along the profile roughly ranging from 24 m (79 ft) to 213 m (699 ft) in the buried valley. The refraction survey indicated average bedrock velocities of 3956 m/s (~13000 ft/s) and depths ranging from about 80 to 700 feet (24 to 213 meters), which is consistent with the reflection results and with a valley fill of unconsolidated sand and clay and limestone bedrock.

Master of Science, The Ohio State University, 2024, Earth Sciences

Strike-slip fault zones are complex regions of deformation generally centered around a centimeters-wide fault core that hosts intensely deformed fault gouge. Surrounding the fault core is the 10's to 100's of meters thick fault damage zone marked by predominantly brittle inelastic off-fault deformation (OFD). In outcrop, OFD takes the form of fractures, deformation bands, subsidiary faults, and in some cases, pulverized rocks. At the microscopic scale this deformation may be achieved by granular flow, cataclasis, and/or volumetric deformation. Different styles of OFD are related to specific parts of the earthquake cycle, some of which are the result of dynamic, coseismic processes while others are produced by long-term, quasistatic processes that aren't tied to any particular step of the seismic cycle. Dynamic processes produce brief, strongly perturbed stress fields surrounding the fault core leading to a unique damage signature. Quasistatic processes lead to deformation consistent with the long term regional stress field. Discrepancies in fracture energy estimates from large natural earthquakes compared to laboratory high speed friction experiments can be explained if OFD plays a bigger role in large earthquakes (>Mw 6.6-6.8) versus smaller earthquakes. Fracture energy is a critical component in assessing seismic hazard and thus warrants a solution for discrepancies at large earthquake magnitudes – the first step of which is to study the OFD in natural fault zones and identify deformation elements uniquely associated with dynamic rupture. I performed geologic mapping and characterized damage zone deformation on the southern San Andreas Fault (SSAF). A field site at Ferrum, CA exposes the damage zone of the SSAF in relatively well-known stratigraphy and additionally hosts a creepmeter and abundant InSAR datasets. I identify deformation elements (namely, pulverized crystalline rock and randomly oriented shear deformation bands) associated with dynamic rupture, and a (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Earth Sciences

Knowledge of the distribution of Fe2+ and Mg between olivine and melt (the distribution coefficient, KD) is crucial to understand the origin and evolution of magmas. However, there is disagreement regarding which variables (temperature, melt composition, and oxygen fugacity – fO2) influence the value of KD, as well as the magnitude of their effects. To evaluate the dependence of KD on these variables, data were compiled from literature consisting of equilibrium olivine-melt pairs in experiments at controlled temperature, fO2, and 1 atm pressure. The results confirm that KD is essentially independent of temperature and fO2. However, it is strongly dependent on melt composition (particularly the concentration of silica and alkalis). An evaluation of different published formulations for KD using these data demonstrates that the expression of Gee and Sack (1988) is the most accurate and precise. Furthermore, a new and simpler model based on variation of KD with silica and alkalis has been fit to the olivine-melt database. This reproduces KD with the same accuracy and precision as the Gee and Sack (1988) formulation. The olivine-melt database also illustrates that KD can be used to calculate the proportion of the different valence states of iron in the melt (the Fe3+/ΣFe ratio), which cannot be measured using routine analytical techniques. The melt Fe3+/ΣFe can then be related to fO2 using empirical relationships. This method, referred to as the Olivine-Melt Equilibrium (OME) method, reproduces the fO2 imposed on the experiments within ±0.3 log units. This method was applied to compiled data for natural samples from literature from mid-ocean ridges, ocean islands, back-arc basin spreading centers, and volcanic arcs. Olivine-melt calculated values of fO2 for each location investigated agree with the results of independent techniques. These include compiled measurements of Fe3+/ΣFe ratios using Fe K-edge μ-X-ray Absorption Near Edge Structure (XANES) spectroscopy, as we (open full item for complete abstract)

Master of Science (MS), Ohio University, 2024, Geological Sciences (Arts and Sciences)

Sediment transport affects how cave passages grow and behave during floods. Sediment begins moving once a critical shear stress is reached. Often, assumptions about variables affecting shear stress are necessary to model sediment transport and a variety of methods have been used to calculate shear stresses to determine when sediment transport is likely to occur. I studied sediment transport in a narrow, steep vadose passage in Fullers Cave, located in Greenbrier County, West Virginia, USA. Flow depth measurements by five in-cave probes were used with known discharges to reconstruct stream processes and sediment transport along a 95-meter reach. A sediment trap and sediment tracing were used to monitor sediment movement. To date, the largest trapped cobble had a critical shear stress of 218 N m-2, which is similar to shear stresses previously determined in the cave. Tracer rocks have been monitored twice with different sets of rocks. The mobilized tracer grains in the first experiment had a median grain size of 74mm with a maximum b axis length of 268mm. The median grain size is comparable to the 77mm median grain size obtained from Wolman counts in the affected reaches prior to the floods. The d84 grain size is being used for a second tracer rock study, but recent floods have been too small to move significant amounts of sediment. Nonetheless, floodwater velocities observed to date are between 1.5 and 1.7 m s-1 in the study reach for moderate floods and velocities during floods that moved a few rocks had maximum velocities of 0.77 and 2.1 m s-1. The critical shear stress for the largest entrained tracer rock in the second experiment was 126 N m-2, which is substantially less than shear stresses of 278-628 N m-2 generated by moderate floods recorded by an earlier study with discharges of ~1.5 m3 s-1. The results indicate that the cave is capable of transporting larger grains than are currently found in the study reach, which is consistent with intermittent exposures (open full item for complete abstract)

Master of Science, University of Akron, 2024, Geology

Partial melting of hydrous phases such as amphibole, biotite, and muscovite occurs in orogens where distributed ductile thinning is causing exhumation of mid- to lower-crustal rocks. The partial melting of these hydrous phases contributes significantly to the physical and chemical evolution of the crust, as well as affecting the crust's strength. The Si-rich melts generated from partial melting reactions of mid- to lower-crustal assemblages migrate toward the upper crust leaving a more mafic restite. Previous laboratory experiments conducted on amphibole-, biotite-, or muscovite-bearing rocks performed at rapid strain rates (10-4/s to 10-5/s) result in brittle deformation due to high local pore pressures. These rapid experiments suggest this brittle behavior is the likely mechanism causing melt segregation in the crust. However, field evidence and slower strain rate experiments (10-6/s to 10-7/s) suggest that crystal plastic processes may be dominant during syndeformational partial melting. To investigate grain-scale melt segregation mechanisms in a common lower crustal protolith, I performed a suite of axial compression and general shear experiments on an amphibole-bearing source rock during syndeformational partial melting at T = 800-975°C, Pc = 1.5 GPa, at a strain rate (ε) of 1.6 x 10-6/s. I also performed axial compression experiments on a biotite-bearing gneiss and a muscovite-bearing quartzite at T = 950°C, Pc = 1.5 GPa, at a strain rate (ε) of 1.6 x 10-6/s to compare the differences in melt development depending on which hydrous phase is partially melting. The Nemo Amphibolite (d = 140 ± 85 μm) is composed of 62 vol% amphibole (Fe-hornblende), 27 vol% plagioclase (andesine; An30Ab69Or1), 8 vol% quartz, and 3 vol% titanite. The biotite-bearing gneiss (d = 80 +/- 40 microns) consists of quartz (43 vol%), plagioclase (andesine (An22Ab77Or1); 40 vol%), biotite (16 vol%), and ~1 vol% muscovite/Fe-Ti oxides. The muscovite-bearing quartzite is composed of 90 vol% q (open full item for complete abstract)

Master of Science, The Ohio State University, 2023, Earth Sciences

Water tables in coastal aquifers respond to a variety of hydrologic forcings, including precipitation, coastal flooding, and tides. Water table fluctuations induce the flow of water and air across shallow organic-rich soils, which affects the supply of nitrogen (N), dissolved organic carbon (DOC), oxygen, and other reactive solutes, and leads to changes in water quality. My goal was to investigate reactive N transport near a fluctuating water table using a meter-long column containing reconstructed coastal soil and aquifer material from a Mediterranean site (Mataro, Spain). I continuously monitored in-situ redox potential, soil moisture, and matric potential and collected frequent pore water samples for analysis of dissolved inorganic N species and DOC over 16 days. Local groundwater containing high concentrations of nitrate-N (16.5 mg/L) was supplied to the column base. As the water table rose and fell, redox potential fluctuated widely from -600 to 600 mV within the zone of variable saturation. Redox potential typically increased upon saturation and declined again as soils drained, with more subtle changes occurring during the first wetting and drying cycle and greater changes occurring during repeated cycles. Pore water analysis shows that nitrate was depleted near the zone of fluctuation, while ammonium, nitrite, and DOC were elevated, relative to groundwater entering the base of the column. When the water table rose, nitrate was transported up into soils from the groundwater, and concentrations fell as denitrification occurred in the presence of DOC. At the end of the experiment, the column was flooded with seawater at the top of the column. Seawater mobilized ammonium, nitrate, and DOC in the vadose zone, but nitrate did not accumulate beneath the water table, presumably due to enhanced denitrification. Seawater flooding therefore has the potential to mobilize accumulations of N in soils if an ample supply of DOC is not present. In the absence of seawater inun (open full item for complete abstract)

MS, Kent State University, 2023, College of Arts and Sciences / Department of Earth Sciences

Hydrodynamic dispersion emerges from the architecture of sedimentary rocks specific to depositional environments. Geologic heterogeneity, resulting from depositional processes, plays a critical role in describing the dispersion phenomena in sedimentary rocks. Questions remain in quantifying dispersion as a function of pore-scale heterogeneity and determining the spatial length scale needed for the solute transport phenomenon to transition from non-Fickian characteristics to Fickian characteristics. In this investigation, we digitally construct three pore-scale porous domain geometries to incorporate a) sedimentary architecture, i.e., graded, laminated, and random arrangement of grains, and b) a variety of pore-size distributions in each of the synthetic sedimentary architecture that accounts for variability resulting from sediment size distributions. We quantify geological heterogeneity in constructed sedimentary architectures by the standard deviation (σg) in the lognormal distribution of pore sizes. Flow and transport phenomenon is simulated using computational methods at different flow rates or Peclet number (Pe) regimes. Residence times and variance in flow field velocities are investigated as a function of σg. Hydrodynamic dispersion is quantified as a function of σg and shown to exhibit an exponential dependence. Flow rate effects on hydrodynamic dispersion display unique power-law exponents describing the impact of geologic heterogeneity. We observe a distinct spatial length scale needed for the transition from non-Fickian to Fickian transport. A magnitude of non-Fickian effects is quantified which highlights the importance of utilizing fully Fickian transport coefficients. Finally, the scaling behavior of dispersivity at the pore-scale is quantified, and the effects of flow rate and σg on dispersivity are described.

Master of Science, University of Akron, 2023, Geology

Within the mid to lower continental crust distributed ductile thinning occurs, in orogens that form mountains like the Himalayas and Appalachia, due to a weak middle to lower crust that deforms laterally in response to loading of a thickened, cold upper crust. This thinning destabilizes large orogens and causes the exhumation of hot and weak rock from the mid to lower crust that begins to partially melt. This melting further weakens the rocks and may affect the deformation mechanisms operating in the crust. Melting has been seen to have impacts on the deformation mechanisms and resulting lattice preferred orientations (LPO) that form in olivine-basalt aggregates (Holtzman et al., 2003). To investigate the effects of partial melting on deformation mechanisms and LPO development in two common foliated felsic rocks, I performed general shear deformation experiments on a fine-grained quartzite and fine-grained gneiss at T = 800°C, 850°C, 900°C, 950°C, or 975°C, P = 1.5 GPa, and strain rate of 6*10-5/s. The quartzite (grain size ~30 microns) is composed of 90% quartz and 10% muscovite. The fine-grained gneiss (grain size ~50 microns) is composed of 43% quartz, 40% plagioclase, 16% biotite, and 1% accessory minerals. The foliation in the slices of each rock was oriented parallel to the shear plane between Al2O3 shear pistons with a cut made at 45° to the compression direction. Experiments were performed at a range of temperatures to change the melt fraction present in the rocks during deformation (Melt = ~0%, 0.25%, 0.5%, and 1%). The yield stress of Moine Thrust quartzite decreased as a function of increasing temperature from ~1000 to ~300 MPa. However, all the experiments with melt present (T equal to to greater than 850°C) significantly strain hardened after a shear strain (g) of 1. This hardening may be due to the presence of melt along grain boundaries which is absorbing water from the recrystallizing quartz grains which slows diffusive recovery in quartz. The Gne (open full item for complete abstract)

Master of Science (MS), Ohio University, 2023, Geological Sciences (Arts and Sciences)

Each cave is unique from structural or hydrological perspectives, which often complicates the prediction of subsurface flow routes needed for planning the economic development of karst landscapes and responding to groundwater contamination. This is true of the Great Savannah Cave System (GSCS) in southeastern West Virginia since the growing city of Lewisburg is expanding northward over the 50-mile-long cave system. The GSCS is the sixth-longest cave in the United States and pollution is affecting the cave in many still poorly defined ways. We report findings of a geological study of critical passages in GSCS as these findings to relate to subsurface flow paths and the prediction of unknown pathways. McClung Cave is in Greenbrier County in which the primary lithology is a Mississippian-age formation containing limestone and minor shales with negligible amounts of sandstone. Karst features of the GSCS formed along the contact zone between the Greenbrier and an underlying shale where streams sink upon encountering the limestones. Dip- and strike-oriented flow routes are analyzed using structural contouring, structural mapping, and passage morphologies. Vadose infeeders are generally oriented downdip, but with significant variability and hard-to-predict meandering due to geological features too small to be resolved in general geological mapping. Strike-oriented collector passages receive vadose streams from updip but are epiphreatic with infrequent filling during low recurrence interval floods. However, geological structures are only one control on the GSCS, and we present analyses of the host bedrock, including the qualitative results of thin-section studies designed to understand stratigraphic perching and selective cave development in certain lithologies. The information gained can be used to make predictions about flow routes and master conduits that have yet to be observed once additional data is collected.

Master of Science, The Ohio State University, 2022, Civil Engineering

Acid mine drainage (AMD) and the associated mine land sediments are a valuable source of rare earth elements (REEs) and critical minerals with concentrations of REEs in AMD often orders of magnitude higher than those in river water and seawater. Recovering REEs while cleaning up AMD provides the potential to offset the cost of reclamation. In this study, we are evaluating the REE content and distribution in the sediments associated with two AMD locations in SE Ohio that exhibit high REE content. The study sites, ‘Flint Run' and ‘Howard-Williams Lake', are complex sites with multiple past remediations and reclamation attempts that continue to produce AMD with REE concentrations up to 0.9 mg/L and 1.9 mg/L, respectively. Soil cores were collected from the two sites using an auger and split-spoon sampler. Samples were collected at approximately five-foot increments and trace element and REE concentrations were analyzed on digested samples using inductively coupled plasma atomic emission spectroscopy. The mineralogy of the sediments was analyzed with a high-resolution X-Ray diffractometer. Our results show the layers of fill used to reclaim the sites were not uniform spatially or with depth and were comprised of a mixture of silty clay, underclay, coal refuse, shale, and sandstone. Samples identified as being associated with coal (i.e., clay with coal fines and coal refuse), regardless of the depth measured, had higher REE concentrations (up to 437.9 ppm total REE) in comparison to the other compositional layers studies (~36 ppm total REE). Samples associated with coal had concentrations ranging from 4.2-126 ppm for Ce to 4.5-52.6 ppm for Nd. These layers also exhibited elevated concentrations of Fe and Al. At water pH values of 5.1-6.6, REEs were expected to precipitate with Fe and Al minerals into the sediment, which was consistent with the pH value of water collected during sample collection at Howard-Williams Lake. Statistical analysis and XRD results indicate that (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2022, Geology

Grass carp, an invasive species moving into the Great Lakes, present deep concerns regarding environmental impact they will have on native plants and fishes. Previous studies utilized otolith microchemistry (Sr:Ca and Ba:Ca) to identify grass carp spawning locations in Lake Erie with limited success due to overlap of the Sr:Ca values under different flow conditions in Sandusky and Maumee Rivers, and uncertainty in the water:otolith Sr:Ca partition coefficient (Whitledge et al., 2021). This study aimed to test the use of strontium isotopes (87Sr/86Sr) to differentiate Sandusky and Maumee Rivers as natal locations for these fish: strontium isotopic ratios are not as strongly affected by flow rate as elemental ratios. Isotopic strontium values were established over a range of flow rates (high flow for spawning, low flow as a control) and these isotopic ratios did not vary significantly over differing flow rates at the same locations (with one exception). Strontium isotope values vary within water samples from the Sandusky River watershed due to changes in bedrock, with a general decrease in the 87Sr/86Sr values (and K concentrations) going downstream in the main channel (and a general increase in Ca, Mg, and Sr) from transitioning shale into dolomitic carbonate bedrock. Strontium isotope values for otoliths (common carp) from impounded upland reservoirs in the region match the strontium isotope values in the water, confirming there is no isotopic fractionation between water and otoliths. Strontium isotope values from core regions of grass carp from Whitledge et al. (2021) were grouped into three apparent clusters (corresponding to Lake Erie, Maumee River, and Sandusky River), and reassigned natal origin of some fish classified by Whitledge et al. (2021). The 87Sr/86Sr values of the Sandusky River otolith cluster were, on average, below Sandusky River water 87Sr/86Sr values, suggesting these fish may have spawned in the Sandusky River, quickly moved into water with l (open full item for complete abstract)

Master of Science (MS), Ohio University, 2022, Geological Sciences

Currently, there is a lack of quantification to the hydrogeologic sensitivities (groundwater level, soil textures, waters chemical condition, precipitation quantities, soil, and air temperature) that contribute to the fluctuating emissions from wetlands. Focusing on nitrous oxide (N2O) production rates within a palustrine groundwater-dependent ecosystem in Gunsan South Korea named Baeksukjae, a novel methodology has been applied to measure the emission rates of N2O and N2 gases from the field site. Five sampling sites were utilized where a total of 246 gas, 59 water, 38 soil, and 52 kinetic cell samples were collected. During sample collection, field parameters of pH, conductivity, dissolved oxygen, redox potential, soil, air temperature, and groundwater levels were measured daily over a 4-week field survey conducted in summer, 2021. Field data were then used within a denitrification and decomposition (DNDC) model for calibration. Water ion data at all sites reinforced several expected relationships such as the diminishment of nitrification during moments of high silicon concentration, increased delivery of alkaline earth metals during moments of higher acidity, and strong positive correlations between water electrical conductivity and alkalinity. Although the chemical diversity of water samples taken during the sampling stint are high, investigation revealed only a few significant parameters that vary NO2 emissions. Dramatic changes in water chemistry can be attributed to high precipitation events. Precipitation events diluted chemical constituents directly, as well as delivered nutrients to the wetland through runoff. Site mA consistently showed increases in nitrate (NO3-) concentrations (maximum values of 19.1 mg/L) in the groundwater and increased N2O gas production rates that mirror the frequency of precipitation and temperature variations. Analyzing kinetic cell data confirmed initial hypotheses that the production (open full item for complete abstract)

Master of Science, Miami University, 2022, Geology and Environmental Earth Science

Observations of Allan Hills 81005 via PLM and SEM-EDS are consistent with the classification of anorthositic regolith breccia. Clasts of anorthosite, basalt, granulite, and impact melt breccia are present. The brecciated matrix is dominated by plagioclase, minor (clino)pyroxene, and rarer olivine in addition to trace oxides and sulfides. Phosphates, spinels, glass spherules, and crystalline spherules are rare and not ubiquitous in studied sections. In section -92, a spinel-bearing dunite clast is present alongside several pink spinel-bearing troctolitic clasts. The composition of dunitic olivines is consistent with the lunar Mg-suite as exemplified by Mg#, CaO, Cr, and Mn systematics. Compositions also overlap with those from dunite sample 72417. Both are distinct from non Mg-suite dunites in 74275 and the modeled composition of early-formed LMO cumulates. Spinels within the dunite clast are also consistent with spinels within Mg-suite dunites (Mg# ~50, Cr# ~70) while troctolitic pink are consistent with Mg-suite spinel troctolites (Mg# ~70-80, Cr# <10). Collectively, the clast and mineral assemblages support an origin of ALHA81005 from the lunar highlands. The observation of a lunar dunite contributes to our understanding of Mg-suite magmatism during lunar differentiation.

MS, Kent State University, 2022, College of Arts and Sciences / Department of Earth Sciences

This study evaluated the trends in both predation and biodiversity of bivalves during the dynamic late Cenozoic record within the Chipola, Tamiami, Jackson Bluff, and Bermont formations in northwest and central Florida. Shifts in predation rates and bivalve diversity were evaluated over short timescales within the Bermont Formation and over longer timescales in the Chipola, Tamiami, and Jackson Bluff formations. Shifts in diversity and predation on very short timescales were reflected in bivalve assemblages within different beds of the Bermont Formation. Long and short term changes in bivalve faunal composition and predation rates were evaluated in the context of climate change and sedimentary environment. The relationships between predation and diversity shifts within the Bermont Formation are reflected in diversity, abundance, and rate of boring. There were measurable differences in faunal abundances, greater diversity, and changes correlated with climatic shifts as well as overall variations in predation intensities. The Tamiami Formation preserved lower overall abundances, higher levels of diversity, and low predation within each bivalve species. However, the lower Bermont Formation exhibited higher abundances, lower overall diversity, but moderate predation on bivalve species. The Jackson Bluff Formation expressed high abundances, low diversity, and high levels of predation. The Chipola Formation contained high abundances, moderate diversity, but very low predation.

Master of Science (MS), Bowling Green State University, 2022, Geology

The mining of aggregate is vital to preparing concrete and building constructions; however, there are some known impacts that aggregate mining can cause on both hydrologic and ecological systems. This study incorporates field and modeling studies to understand the potential influence of mining on groundwater and surface-water interacting hydrologic systems. The study site is an active, 265-acre mining site located in Washtenaw County, Michigan, which has two artificial lakes. The goal was to develop a three-dimensional hydrologic model, HydroGeoSphere (HGS), for the mining site and apply it to evaluate the impacts of mining activities such as quarry expansion and dewatering on local groundwater and surface-water systems. To protect the wetlands around the area, there was a desire to maintain a stable water surface elevation for the Lakes throughout the expansion. The model was used to simulate both surface and subsurface waters in the site and their hydrologic dynamics as responses to weather or climatic variations and mining expansions described above, which changed the lake bathymetry. The model domain encompassed 2,038 acres of land, which has a pseudo rectangle shape bounded by the Raisin River being the boundary on the east side and no-flow boundaries along the remaining three sides. The model used a finite-element mesh generated with AlgoMesh software, which consists of nine vertical layers and a total of 2778 nodes and 5177 elements. Primary input data to the HGS model include land-surface elevations, weather data (daily precipitation and temperature) obtained from a nearby weather station, potential evapotranspiration values calculated with a Penman-Monteith method and geology and bathymetry data from field investigations. The model was satisfactorily calibrated against water level data observed in the two lakes and four water-table monitoring wells, spanning a period from January 2018 to December 2020. After calibration, (open full item for complete abstract)

Master of Science (MS), Wright State University, 2021, Earth and Environmental Sciences

The Theis Environmental Monitoring and Modeling Site is a field research facility, located on the Great Miami River in southwest Ohio, dedicated to the study of hyporheic zone processes. The site is underlain by an aquifer on the order of 21 meters thick, comprised of fluvial deposits. The permeability of the aquifer sediments was quantified both from one large scale hydraulic test (~100 m radial distance) and from grain-size analysis of 119 small-scale core samples (~20 cm length each). The permeability determined from the large-scale hydraulic test is 98.9 Darcies. The test also gave a value for specific yield of 0.25. The geometric mean of the small-scale measurements is 88.3 Darcies, close to the value of the large-scale measurement, and within the central tendency of the distribution of previously published measurements. The aquifer contains an inferred hierarchy of sedimentary architecture, with compound bar deposits comprising unit bar deposits, and unit bar deposits comprising stratasets with different grain-size facies, including sand, gravelly sand, sandy gravel, and gravel. The stratasets are less than a meter thick and less than 10 meters in length. Intervals of sand facies make up 18.5% of the aquifer, have a mean thickness of 0.75 m (standard deviation (σ) of 0.37 m), a mean permeability of 86.8 Darcies (σ of 47.8 Darcies), and a mean porosity of 36% (σ of 4%). Intervals of gravelly sand facies make up 25.2% of the aquifer, have a mean thickness of 0.96 m (σ of 0.46 m), and a mean permeability of 73 Darcies (σ of 49.9 Darcies), and a mean porosity of 28% (σ of 3%). Intervals of sandy gravel facies make up 36.1% of the aquifer, have a mean thickness of 1.00 m (σ of 0.79 m), and a mean permeability of 84.9 Darcies (σ of 49.7 Darcies), and a mean porosity of 25% (σ of 3%). Intervals of gravel facies make up 20.2% of the aquifer, have a mean thickness of 1.10 m (σ of 0.74 m), and a mean permeability of 670 Darcies (σ of 1170 Darcies), and a me (open full item for complete abstract)