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Liu, TingtingWater Behavior on Olivine Surfaces
Doctor of Philosophy, The Ohio State University, 2017, Earth Sciences
Water-rock interaction is one of the most active topics in geochemistry. Olivine group as one of the most important rock-forming minerals extensively occur in the Earth's crust and the upper mantle. The stability and reactivity of olivine minerals in ambient C-H-O fluids has drawn great attention. All the complex surface and bulk reactions occurring between the mineral and surrounding fluids starts with the water on the surface. But how water molecules interact with olivine minerals on the surface on an atomistic/molecular level is still less studied. This work examines the interaction between water and olivine mineral surface, in particular, from the energetics in static state to its structure and dynamics, and vibrational properties of the water molecules on the surface, thus providing a complete picture of molecular behavior of the surface water. This investigation use computational/simulation (first-principles calculations and classical molecular dynamics simulation) tools to calculate the energetics and the dynamic properties. Neutron scattering experimental data are also used to support the dynamic and vibrational property calculations. Water molecule adsorption energy calculations via density functional theory (DFT) calculation is fulfilled by introducing different cation dopants on the forsterite(010) surface as they naturally occur in the crystal structure of olivine minerals as trace elements. It shows that Mg-H2O has the strongest adsorption energy, and the alkaline earth (AE) and transition metal (TM) cations form different types of bonding with H2O, i.e., electrostatic force dominated bonding and covalent bonding, respectively. However, there is no simple trend relating the cation dopant charge or ionic radii to the adsorption energy of water molecule. Instead, it is found that several factors, including surface lattice distortion, ionic size, lattice size (different olivine end members) can together determine the adsorption energy sequence with different metal cations. The structure and dynamics of water molecules on hydroxylated forsterite(010) surface is investigated at 270 K using classical molecular dynamics (MD) simulation. The water structure on the hydroxylated surface is composed of a first weak layer that adsorbs within the trough made by hydroxyl ions and a continuous strong layer on top of the first layer. The dynamic properties pertaining to translation and rotation were investigated separately using intermediate scattering functions (ISF). The translational diffusive motions derived by simulations qualitatively match with the fast and slow motions observed in the experiment. The rotational motion of water molecules and motions of the flexible hydrogen atoms on the surface calculated by simulations is found to be out of the observational energy window of the instrument. MD simulations and inelastic neutron scattering (INS) are used to study the vibrational behavior of water on forsterite surface. Both techniques derived a broad libration band feature by examining the first adsorbed water layer on the surface. MD simulations discover that Ow interacts with the surface Mg atom, and water molecules form an ordered Ih-like ice structure by the network of hydrogen bonding at 10 K. Simulated vibrational data at 150 K was used to compare with INS data at 10 K, avoiding the limitation of classical MD to account for quantum effects that might be significant at 10 K. Confining effect was observed by the simulations, as the molecules near to the surface exhibit smaller bending and stretching magnitude than the free molecule. This works sets up the stage for further investigation on other key geochemical process and could aid in more for water-rock reaction mechanism understanding among C-O-H fluids.

Committee:

David Cole (Advisor); Aravind Asthagiri (Committee Member); David Tomasko (Committee Member); Wendy Panero (Committee Member)

Subjects:

Geochemistry; Geology

Conte, Elise RAPPLICATIONS OF ISOTOPES TO MAGMATIC PROCESSES, ERUPTION AGES, AND NUCLEAR FORENSICS
Doctor of Philosophy, Miami University, 2017, Geology & Environmental Earth Science
This dissertation comprises four studies that apply radiogenic isotopes and 14C as primary tools to investigate problems in igneous petrology and environmental contamination. Two studies utilize uranium (U) isotopes to investigate U contamination related to the former Fernald Feed Materials Production Center (FFMPC) in southwest Ohio. Two other studies utilize Sr, Nd, Pb isotopes, U-series disequilibria and 14C to assess the magmatic evolution and timing of explosive eruptions of Sete Cidades volcano, Sao Miguel, Azores. Two studies examine the utility of tree bark for resolving the areal extent of atmospheric U contamination, using several locations in southwest Ohio that processed U. U concentrations up to ~400 times local background levels, along with progressively more depleted and enriched 235U/238U and higher 236U/238U as the FFMPC is approached, demonstrate the presence of anthropogenic U in the environment, with the minor isotope 236U serving as the most sensitive tracer. Atmospheric dispersal models demonstrate that a 5 um U-rich particle can be transported ~38 km from the FFMPC, providing a mechanism for the non-natural isotopic 236U/238U observed in Hamilton and Oxford, OH. Scanning electron microscopy revealed U-rich particles in tree bark within 1-3 km of the FFMPC. Two studies evaluate the petrogenetic processes and timescales associated with the P1-P17 deposits at Sete Cidades volcano. One study presents the first detailed petrographic, geochemical, and isotopic analyses of the Sete Cidades P1-17 eruptive products, and demonstrates that trachyte pumices from P1-P17 are primarily derived through fractional crystallization of a common parental magma, involving discrete batches of magma following distinct fractionation paths. Isotopic variations among whole rock, sanidine, and glass require the presence of xenocrystic sanidine and assimilation of small degree non-modal, partial melt of syenite wall rock similar to Sete Cidades xenoliths. The second of these studies aimed to better constrain the eruptive timing and the impact of volcanic outgassing on 14C ages. 14C data from paleosols in the P1-P17 eruptive sequence were compared to maximum ages from 226Ra-230Th disequilibria in pumices. We present the first age constraints for the P1 and P8 deposits, and further constrain the age of the P17 deposit. 14C data from modern terrestrial gastropods demonstrates the current contribution of volcanic degassing to 14C ages near volcanic centers. New ages constrain the average eruptive recurrence interval for the P1-P17 deposits at ~220 years. Together these four studies highlight the applicability of isotopic tools to a wide variety of earth systems and scenarios.

Committee:

Elisabeth Widom (Advisor); Claire McLeod (Committee Member); John Rakovan (Committee Member); Paul Tomascak (Committee Member); William Renwick (Committee Member)

Subjects:

Atmospheric Sciences; Environmental Geology; Environmental Science; Environmental Studies; Geochemistry; Geology

Keywords:

Isotope; Nuclear forensics; Environmental contamination; Fernald; Tree bark; Azores; Sete Cidades volcano; Volcanic ages; Paleosol; Gastropod; Carbon-14; U-series disequlibria

Montanye, BoChanges in biological production and lake chemistry in Lake Tanganyika over the past 400 years
Master of Science, University of Akron, 2016, Geology-Environmental Geology
Changes in lake level have had a noticeable impact on the chemistry and productivity of Lake Tanganyika, Africa. Downcore analyses of biogenic silica (BSi), organic carbon, δ15N and δ13C isotopes suggest that productivity began to decline at approximately 1750 CE with a temporary peak during a lake level increase in the late 1800s. The lake level increase of the late 1800s is marked by variations in the sedimentary record by increases in carbonate (>70%), organic carbon (>10%), and BSi (~5 wt. %). Bulk sediment δ15N, organic matter δ13C, and carbonate δ18O data generally show an inverse relationship to the BSi, organic carbon, and carbonate data in the shallow water cores during the lake level increase. One possible interpretation of this inverse relationship is that there is a shift in ecological composition of the primary producers of Lake Tanganyika to nitrogen fixers during the period of increased carbonate and lake level. As productivity began to decline again after the late 1800s lake high stand, diatoms were surpassed by nitrogen fixing phytoplankton, leading to lowered δ15N and δ13C values. Since the early 1900s, productivity of the lake has remained low at values similar to the period before the lake level increase (<3 wt. %). These observations are similar to prior work; however, my results suggest that the decline in primary production may have occurred earlier at these sites than previously inferred.

Committee:

James McManus (Advisor); John Peck (Committee Member); John Senko (Committee Member)

Subjects:

Geochemistry

Keywords:

Lake Tanganyika; geochemistry; biogenic silica; productivity; lake level change; isotopes

Philippoff, Karl StevenAn Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data
Master of Science, The Ohio State University, 2014, Geological Sciences
The interpretation of variations in oxygen isotopes ( d18O) within tropical ice core records have been a subject of much debate. In this study the ice core record from Dasuopu (28 23 N, 85 43 E) in the central Himalayas was compared with two coral composite records derived from Indian (Chagos Islands, Mafia, Mahe, Malindi, and Mayotte) and Pacific (Kiritimati, Maiana, Nauru, Palmyra, and Tarawa) Ocean corals, precipitation data from the Global Precipitation Climatology Center (GPCC) v6 and Indian monsoon subdivisions, the Nino 3.4 index, sea surface temperature (ERSST v3b), and air temperature data (NCEP 20th century reanalysis) to examine its relationship over interannual, 2-8 year, and multi-decadal timescales. Coral records represented reliable, consistent, and highly resolved proxy records of SST variability over the length of their respective records and provided a comparison for the results derived from the SST reconstructions. The results from these analyses indicate that the Dasuopu record can be best understood in a hierarchical manner. Over interannual and 2-8 year timescales, the variability of the Dasuopu oxygen isotopic record is dominated by local and regional rainfall variability which are both strongly associated with the variations in the strength of El Nino-Southern Oscillation (ENSO). However, over decadal and especially multi-decadal timescales, the variation in its isotopic record is strongly driven by long-term trends in air and sea surface temperature in regions upwind of the ice core location. These relationships were highly significant and were observed in both the coral composite and instrumental datasets, making these results more robust. A multi-regression model constructed using the summer monsoon rainfall from the East Uttar Pradesh monsoon subdivision, the summer mean Nino 3.4 index and air temperature anomalies in a region bound by 20-28 N, 80-88 E described 27% of the variance in the Dasuopu d18O record between 1886 and 1996, with temperature the most important parameter. This strongly suggests that these three parameters control a large degree of the variability observed in the Dasuopu d18O record over this time frame.

Committee:

Lonnie Thompson (Advisor); Andrea Grottoli (Committee Member); W. Berry Lyons (Committee Member)

Subjects:

Climate Change; Geochemistry; Paleoclimate Science

Keywords:

tropical ice core; coral; Himalaya; El Nino-Southern Oscillation; climate proxy; oxygen isotopes; monsoon; temperature effect; amount effect;

Al-Qattan, Nasser M E N A A Interpretation of Oxygen Isotopic Values (d18O) of North American Land Snails
Master of Science, Miami University, 2014, Geology & Environmental Earth Science
Modern land snail shells were collected along a north-south latitudinal gradient in North America, from 30°N to 58°N, to investigate the environmental controls on their oxygen isotopic composition (d18O) at a coarse spatial scale. The d18O shell composition is mainly a function of the d18O of precipitation, which gets lower at higher latitudes in response to lower air temperatures. Two exceptions were shells from two fens. The relatively low d18O shell composition from one fen was linked to the relatively negative d18O composition of groundwater. Calculations using a flux balance model for gastropod d18O suggest that the relatively high d18O shell composition from the highest-latitude fen might be related to low relative humidity conditions during the summer months when snails were active. LGM-dated shells were found to have higher d18O values than local modern shells. Using the model, this finding could be in part explained by a period of enhanced aridity, higher d18O values of the summer precipitation and/or the influence of 18O-enriched ocean waters, which is also suggested by other studies worldwide for some periods in the Pleistocene.

Committee:

Jason Rech, PhD (Committee Chair); Currie Brian, PhD (Committee Member); Yanes Yurena, PhD (Committee Member)

Subjects:

Geochemistry; Geology; Paleontology

Keywords:

Land snail shells; Stable isotope composition; Oxygen isotopes; Paleoclimate; Last Glacial Maximum; North America; Quaternary

Eyerdom, Timothy J.Treating Organic Pollutants in Urban Runoff Using Slow-Release Oxidants: Laboratory and Field Investigations
Master of Science (MS), Ohio University, 2014, Geological Sciences (Arts and Sciences)
Non-point source (NPS) contamination is a major concern for urban aquatic environments. This study tested the feasibility of using slow-release oxidants (SR-O) emplaced in storm pipes for treating organic pollutants in urban storm runoff through proof-of-concept laboratory tests and preliminary field investigations in Athens, OH. Release rates of slow-release persulfate (SR-PS), slow-release hydrogen peroxide (SR-HP), and slow-release hydroxide (SR-OH) were estimated through column tests. Results from column tests show that stable release was achieved after 100 hours of testing. Stable release for SR-HP, SR-SP, and SR-OH were up to 2.8x10-3, 5x10-1, and 2.8x10-1 mg min-1, respectively. SR-PS forms were observed to release for two weeks and at 90-100% efficiency. Total organic carbon, chloride, and sulfate concentrations in a two hour storm ranged from 9.8 to 63.4 mg L-1, 6.7 to 23.4 mg L-1, and 6.0 to 59.0 mg L-1, respectively with maximum concentrations shown in the first flush period. Since no organic pollutants were detected in the storm water, pollutant standard solutions were added to storm water samples to evaluate removal efficiencies of base activated SR-PS systems. Base activated persulfate using SR-PS, SR-HP, and SR-OH was found to be the most efficient system in treating organic pollutants within 30 minutes, the estimated residence time of storm water within storm pipes. The proof-of-concept flow-through test demonstrated that up to 60% of pollutants can be removed by the SR-PS/HP/OH within 30 minutes of reaction time in deionized water and between 25-65%, 13-36% less efficient, in storm water. Estimated Cost of using SR-O systems in urban areas can range between 109 (for 168 two hour storms) and 9908 dollars (for 168 two hour storms) per year depending on area and storm frequencies. These results suggest that installation of SR-PS/HP/OH in storm pipes could provide a novel cost effective treatment scheme for organic pollutants in urban runoff.

Committee:

Eung Seok Lee (Advisor); Dina Lopez (Committee Member); Gregory Nadon (Committee Member)

Subjects:

Geochemistry; Geological; Geology

Keywords:

Urban Runoff; Advanced Oxidation Processes; Organic Pollutants

Mukherjee, DibyenduDegradation of Chlorinated Ethenes in Mesocosms Simulating a Constructed Wetland, at WPAFB, Ohio
Master of Science (MS), Wright State University, 2008, Earth and Environmental Sciences
The main purpose of this research was to study the degradation of chlorinated ethenes in upwardflowing mesocosms, simulating a constructed wetland at Wright Patterson Air Force Base (WPAFB) in Dayton, Ohio. This research was intended to compare biogeochemical processes and PCE degradation occurring in the mesocosms and in the field site. This research also tries to look at the effects of vegetation and season on the degradation efficiency of the mesocosms. Twelve PVC column reactors were built within the greenhouse of Wright State University in September 2005 to simulate the hydraulic conditions of a constructed wetland at WPAFB. The columns were filled with wetland soils. Three kinds of wetland plants, Scirpus atrovirens (green bulrush), Carex comosa (longhaired sedge) and Eleocharis erythropoda (spike rush) were planted in nine of the reactors and three were left unplanted (control). Water samples were collected from the reactors for a period of one year and analyzed in the laboratory using a gas chromatography system (HP 6890 GC) to detect the concentration of chlorinated ethenes and methane. Degradation of PCE along with formation of the daughter products TCE, DCE, VC and Ethene were detected in the reactors. Both anaerobic and aerobic degradation processes were taking place within the reactors. Strong seasonal trends seen in the planted reactors were not so evident in the control reactors.

Committee:

Dr. Abinash Agrawal (Committee Chair)

Subjects:

Geochemistry

Keywords:

¿¿¿¿M; reactors; PCE; TCE; methane; WETLAND; ports

Baumann, Justin HThe effects of elevated temperature stress on the acquisition and allocation of carbon to lipids in Hawaiian corals
Master of Science, The Ohio State University, 2013, Geological Sciences
Understanding the complex processes of coral response to, and recovery from, bleaching events is central to our ability to predict the impacts of current and future climate change on coral reef ecosystems. Lipids are key biomolecules within the coral holobiont, serving as structural components, as well as significant energy reserves. With the frequency and intensity of bleaching events expected to rise in the coming decades, it is important to understand how coral lipids will be effected by, and recover from, bleaching. A bleaching experiment, followed by carbon pulse-chase labeling, was performed to investigate the assimilation and allocation of carbon to coral host and endosymbiont tissues (including lipids) over the course of bleaching and recovery. Here, we show that bleaching results in a decline in the allocation of photosynthetically derived carbon to lipids in the first month of recovery, but that photosynthetic carbon allocation had fully recovered after 11 months in both Porites compressa and Montipora capitata. In contrast, the allocation of heterotrophic carbon to lipids was no different between bleached and control corals in the first month for both species. While this pattern did not change after 11 months of recovery for M. capitata, dramatically higher enrichment values in the lipids built with heterotrophic carbon of bleached compared to non-bleached control Porites compressa corals were observed. This suggests that either the corals are still recovering, or that they have acclimated and are better able to resist additional bleaching. Overall, P. compressa catabolizes newly synthesized non-lipid energy reserves and maintains newly synthesized lipids. In comparison, M. capitata catabolizes heterotrophic carbon from feeding and catabolizes some of its newly synthesized lipids to meet metabolic demand while maintaining its existing lipid, protein, and carbohydrate reserves. Due to maintenance of total energy reserves and only a small (yet significant) amount of lipid catabolism, it appears that M. capitata recovers faster and may be more resilient to bleaching than P. compressa.

Committee:

Andrea Grottoli, Dr. (Advisor); Lawrence Krissek, Dr. (Committee Member); John Olesik, Dr. (Committee Member)

Subjects:

Biological Oceanography; Biology; Ecology; Geochemistry

Sulley Addo, TahiruEFFECT OF SAMPLE MISCUT ON DISSOLUTION KINETICS OF CALCITE (104) CLEAVAGE SURFACES
Master of Science (MS), Wright State University, 2013, Chemistry
Calcite is one of the most abundant naturally occurring carbonate minerals in the earth crust, and it is believe to play a crucial role in the long-term effectiveness of geochemical process works such as geological carbon sequestration. Due to the ease in which clean, flat calcite surfaces may be prepared, a lot of dissolution studies have been carried out on its (104) cleavage plane. However in geologic media, natural calcite grains consist of alternate surface terminations that do not display similar crystallographic properties as the (104) cleavage plane. This study focuses on the effect of miscut and step orientation on the long-term dissolution behavior of polished calcite surfaces in close to equilibrium fluid conditions with respect to calcite. The polished calcite surfaces were prepared by tilting the (104) cleavage plane at a varying miscut angle to produce forced obtuse step vicinal, forced acute step vicinal, and fully stepped miscut surfaces. Inductively coupled plasma (ICP) and profilometry results revealed that miscut angle has negligible influence on the average transient, long-term and mean dissolution rates. Furthermore, the ICP and microscopic results from atomic force microscopy (AFM) revealed that in the long-term, crystallographic step orientation is not a dominating influence since all vicinal surfaces as well as the fully stepped surface adopt similar surface morphology and hence exhibit comparable steady dissolution rates. Therefore we conclude that in CO2 sequestration environments, differently terminated calcite surfaces will have similar kinetic behavior in the long-term regardless of their crystallographic properties or step orientation.

Committee:

Steven Higgins, Ph.D. (Advisor); David Dolson, Ph.D. (Committee Member); Ioana Pavel, Ph.D. (Advisor)

Subjects:

Analytical Chemistry; Chemistry; Geochemistry

Zhang, GengxinGeomicrobial Processes and Diversity in Ultra-High Pressure Metamorphic Rocks and Deep Fluids from Chinese Continental Scientific Deep Drilling
Doctor of Philosophy, Miami University, 2006, Geology & Environmental Earth Science
This dissertation investigates the microbial communities and microbe-mineral interactions in ultra-high pressure metamorphic rocks and deep fluids from the Chinese Continental Scientific Drilling (CCSD) project by using geochemical, mineralogical, cultivation and molecular microbiology methods. The drilling site is located in the eastern part of the Dabie-Sulu ultra high-pressure metamorphic (UHPM) orogenic belt at the convergent plate boundary between the Sino-Korean and Yangtze Plates. This integrated approach conclusively demonstrates that microbes can survive in the deep continental subsurface (down to 3350 m) and they play important roles in mineral transformations and elemental cycling. The first half of this study focuses on geochemical conditions and diversity and metabolic functions of microbial community. Characterization of SSU rRNA genes indicated that the bacterial clone sequences shifted form a Proteobacteria-dominated community to a Firmicutes-dominated one with increased depth. From the ground surface to 2030 m, most clone sequences were related to nitrate reducers, with a saline, alkaline, and cold habitat. From 2290 to 3350 m most sequences were closely related to anaerobic, thermophilic, halophilic or alkaliphilic bacteria. The archaeal diversity was low. Most archaeal sequences from the ground surface to 3350m were not related to known cultivated species, but to environmental clone sequences recovered from subsurface marine environments. An important contribution of this research is an enrichment of a thermophilic (optimal temperature of 68°C) organism from 2450m with an ability to reduce Fe(III) and oxidize Fe(II) under different conditions. This enriched organism was capable of reducing Fe(III) in aqueous form and in the structure of clay minerals and iron oxides at acidic pH. This organism was also capable of oxidizing Fe(II) in aqueous form and in the structure of pyrite and siderite. The second half of this dissertation focuses on microbe-mineral interactions by using enriched and isolated cultures to react with clay and iron oxide minerals. Mesophilic and thermophilic iron-reducing bacteria were incubated with lactate as the electron donor and structural Fe(III) in solid minerals as the sole electron acceptor. Extensive mineral reaction took place. One important such reaction was the smectite to illite reaction promoted by mesophilic and thermophilic metal reducing bacteria. This particular reaction highlights the significant role of iron-reducing bacteria in promoting the smectite to illite reaction at high temperature.

Committee:

Hailiang Dong (Advisor)

Subjects:

Geochemistry; Geology

Keywords:

Fe; Drilling Fluids; Nontronite; illite; smectite; microbial

Tortorello, Rebecca DianeApplication of Uranium Isotopes as a Temporal and Spatial Tracer of Nuclear Contamination in the Environment
Master of Science, Miami University, 2012, Geology & Environmental Earth Science
The Fernald Feed Materials Production Center (FFMPC) was established in 1951 to process natural uranium ore and recycled recoverable products. This study tests the utility of sediment cores as a proxy for the degree and timing of anthropogenic uranium contamination, using the FFMPC as a test case. An 80 cm long sediment core was extracted from an impoundment located approximately 6.7km southwest of the FFMPC. The lack of measurable 137Cs in the deepest sample as well as a natural 235U/238U signature and no measurable 236U, are consistent with pre-FFMPC activity. The timing of elevated U concentrations, non-natural 235U/238U (0.00645 to 0.00748), and elevated 236U (236U/238U = 2.1x10-6 to 3.6x10-5) found in the sediment core coincide with the the two largest known U dust releases from the FFMPC. Three local lichen samples were also analyzed, and displayed either EU or DU signatures coupled with elevated 236U, recording airborne U contamination.

Committee:

Elisabeth Widom, PhD (Advisor); William Renwick, PhD (Committee Member); John Rakovan, PhD (Committee Member)

Subjects:

Environmental Geology; Environmental Science; Geochemistry; Geology; Nuclear Chemistry

Keywords:

Uranium; Isotope; Sediment core; Lichen; Fernald; Environmental contamination

Allen, Gerald R.An Analysis of the Fate and Transport of Nutrients in the Upper and Lower Scioto Watersheds of Ohio
Doctor of Philosophy, The Ohio State University, 2011, Geological Sciences

Surface water quality data are available from many public and private agencies across the United States. But, how can they be effectively utilized to help resolve the complex biogeochemical relationships of surface waters? The present study examined available stream and reservoir water quality, stream discharge, and meteorological time-series datasets for the Upper and Lower Scioto watersheds in central Ohio. The focus was on the fate and transport of nutrients, specifically nitrate and total phosphorus, in the streams and surface water reservoirs of these predominantly agricultural watersheds. The study area is composed of seven sub-watersheds, five of which contain major surface water reservoirs. Mean nitrate values for the more “riverine” J. Griggs and O’Shaughnessy reservoirs were more than double those for the more “lacustrine” Hoover and Alum Creek Lake reservoirs, and were at least partially due to the different reservoir morphometries and resultant residence times. Nitrate concentrations have gradually decreased over the periods of record in all four reservoirs. Phytoplankton populations in Hoover and Alum Creek Lake reservoirs are ecologically driven, while populations in O’Shaughnessy and J. Griggs reservoirs are weather and stream flow dependent.

The Big Darby Creek contains no major reservoirs or stream impoundments. From 1973 to 2008, annual-mean discharge ranged from 6.8 m3s-1 to 26.8 m3s-1 with an average of 16.1 m3s-1. Fall months were periods of lowest discharge, with spring to mid-summer months typically having highest discharge values. Nitrate and total phosphorus concentrations exhibited a wide range with means closely similar to the values in O’Shaughnessy and J. Griggs reservoirs. Nitrate concentrations have slowly increased in the Big Darby Creek study area from 1973 to 2010. Quadratic model regression analysis showed nitrate concentration had a strong positive relationship with corresponding daily-mean discharge, but total phosphorus concentration was uncorrelated. Seasonal nitrate and daily-mean discharge trends were positive and similar except for fall, which could have been biased by a lack of concentration data for low flows. An analysis of stream flow dynamics suggests that chloride is primarily associated with ground water and is negatively related to stream discharge. Nitrate concentration is predominantly associated with precipitation generated surface runoff or tile-drained discharges from crop lands. The nitrate reservoir in the soil horizon of the Big Darby Creek watershed is gradually depleted from winter to fall.

A conceptual model for the prediction of nitrate concentration at the USGS gaging station at Chillicothe, terminus of all study area surface water, is the sum of the calculated nitrate concentrations of all seven sub-watersheds. Main components of the model are the calculation of daily discharge and nitrate concentrations for the individual sub-watersheds. The model is specifically designed to capture the effect widespread precipitation events have on individual sub-watershed areas, and can be modified for the prediction of other watershed nutrient concentrations. This study has provided an important first step in the quantitative interpretation of the origin of complexity in the development of understanding of nutrient distribution in large watersheds.

Committee:

Franklin Schwartz, PhD (Committee Chair); Carolyn Merry, PhD (Committee Member); Motomu Ibaraki, PhD (Committee Member); Costa Ozeas, PhD (Committee Member)

Subjects:

Geochemistry; Geology; Hydrologic Sciences; Hydrology; Water Resource Management

Keywords:

Upper and Lower Scioto; fate and transport; nutrients; phytoplankton; reservoirs; conceptual model

DeWitt, Debra J.Assessment of the Water Quality of Stream Discharge into Furnace Run Metro Park, Richfield Township, Summit County, Ohio
Master of Science, University of Akron, 2012, Geology-Environmental Geology
With the growing population, development of large residential houses, commercial and industrial developments, and the construction of Interstate 80 and Interstate 77 interchange, water quality of Furnace Run has become an important issue. Recent studies by the Ohio EPA have found the stream to only be in partial attainment for aquatic life. In 2003 a study by the Metroparks found high dissolved solids in one of the tributaries to Furnace Run that flows through the park. The high dissolved solids were attributed to the ongoing construction of the highway interchange. The purpose of this study was to determine the influence western and eastern tributaries that flow within Furnace Run Metropark have on the water quality of Furnace Run. The land use west of Furnace Run consists of large housing developments; and that to the east consists of highways, an interchange, houses, commercial, and industrial developments. Field work was performed on 23 tributaries, and Furnace Run itself, within the Furnace Run Metropark from June 5, 2010, through April 9, 2011. Water samples were collected nine times during the study period from Furnace Run and its tributaries for water quality analysis for common anion concentrations; and on two occasions, samples were collect for analysis for cation concentrations. The cation and anion data were used to create Piper diagrams to determine water types. Also, suspended sediment load was measured using the Ohio Sediment Stick to find the actual amount of mineral and organic particles transported in the tributaries. This study found that the use of road deicer in the winter months may be contributing to the high concentration of chloride in Furnace Run and its tributaries. The eastern tributaries were affected the most due to their location near the highways. Duration between storm events also had an effect on the water quality of the streams. Pollutants were able to build up on roadways and other surfaces during dry days, which may have lead to the increase in pollutant concentrations in the streams during the first flush from the next storm event.

Committee:

John Szabo, Dr. (Advisor); LaVerne Friberg, Dr. (Committee Member); John Peck, Dr. (Committee Member)

Subjects:

Geochemistry

Keywords:

Furnace Run; water quality; suspended sediment; NE Ohio; Cuyahoga River Watershed

Yu, HuiminLi, Hf and Os Isotope Systematics of Azores Basalts and A New Microwave Digestion Method for Os Isotopic Analysis
Doctor of Philosophy, Miami University, 2011, Geology & Environmental Earth Science

This dissertation includes three projects related to the isotope geochemistry of ocean island basalts (OIB) in the Azores archipelago. Detailed studies of Hf, Os and Li isotope systematics are combined with Sr-Nd-Pb isotopes and trace elements to investigate the nature and origin of mantle heterogeneity beneath the Azores. In addition, new microwave digestion methods have been developed and tested for dissolution of samples for Os isotope analysis.

The first project focuses on Hf-Os isotope systematics of basalts from the Azores Central Group islands (Faial, Pico, São Jorge and Terceira) with HIMU and EM-type signatures. Sub-chondritic 187Os/188Os and ΔεHf signatures on or slightly below the terrestrial εHf - εNd array indicate that the mantle sources of these basalts do not contain significant recycled crustal material. Rather, the sources of the basalts are interpreted to include variable and geographically controlled mixtures of a deeply derived enriched mantle plume, relatively depleted mantle similar to that beneath the Mid-Atlantic ridge, and recycled metasomatized mantle wedge.

The second project focuses on assessing the utility of Li isotopes as a tracer of heterogeneous mantle sources. The δ7Li data of Central Group island (Faial, Pico and Terceira) and São Miguel basalts vary only slightly (+3.1 to +4.7‰), and are all within the range of normal MORB, despite large variations in radiogenic isotopes. Nevertheless, the Central Group island basalts have, on average, slightly higher δ7Li than São Miguel, and exhibit positive correlations with Sr and Os isotopes, and negative correlations with Pb, Nd and Hf isotopes, and are consistent with the interpretations of the Hf-Os isotope study. New diffusion modeling furthermore suggests that mantle heterogeneities induced by subduction processes may be maintained in the mantle for timescales of >2.5Ga.

The third project assesses the utility of microwave digestion for Os isotopic analysis. Compared to conventional Carius tube digestions, microwave digestion is faster and safer, and allows for the use of HF to achieve complete dissolution of silicate samples. This study demonstrated that microwave digestions successfully achieve spike-sample equilibration, have acceptably low processing blanks, and produce yields >90%.

Committee:

Elisabeth Widom, Ph.D. (Advisor); William Hart, Ph.D. (Committee Member); Michael Brudzinski, Ph.D. (Committee Member); Paul Tomascak, Ph.D. (Committee Member); Michael Crowder, Ph.D. (Committee Member)

Subjects:

Geochemistry; Geology

Keywords:

Ocean island basalts; Azores; Faial; Pico; S&227;o Jorge; S&227;o Miguel; Terceira; geochemistry; radiogenic isotopes; lithium isotopes; trace elements; mantle plume; mantle heterogeneity, microwave digestion; osmium separation; distillation

Groshong, Kimberly AnnModeling the Effect of Calcium Concentration and Volumetric Flow Rate Changes on the Growth of Rimstone Dam Formations Due to Calcium Carbonate Precipitation
Master of Science, University of Akron, 2008, Applied Mathematics
Rimstone dams, formed in cave environments and composed primarily of calcium carbonate, are constructed through both chemical and mechanical processes. As calcium rich water flows over a sloped limestone cave floor, calcium carbonate precipitates from the solution. Standard fluid mechanics equations govern the hydrodynamics. Chemical kinetics describe movement through the boundaries and explain the bulk and surface reactions that influence precipitation. The free boundaries, gas-fluid and solid-fluid interfaces, couple the hydrodynamic and reactive transport equations. The chemical kinetics of bulk and surface reactions that result in precipitation are determined. This research focuses on the effect of changing the volumetric flow rate and altering the concentrations of calcium on the growth of the mineral-fluid boundary by developing and solving, through thin-film fluid flow approximations, appropriate hydrodynamic and reactive transport equations. Three general volumetric flow conditions are explored in this paper. The effect of slow, moderate, and fast flow rates under conditions of constant flow; exponentially decreasing flow, modeling drought conditions; and seasonal flow fluctuations about a base rate are investigated. The greatest growth was observed during seasonal fluctuations with a moderate volumetric flow rate. Greatest deposition, near the initial position, was with high concentrations of calcium flowing with a fast flow rate. Further downstream, the largest growth required small concentrations of calcium, which maintained a high pH condition in the system. From the developed equation for the mineral boundary, growth was affected by pH conditions driven from bulk reactions and influenced by degassing of carbon dioxide and surface reactions from the alterations in calcium concentration, ultimately driving the system pH.

Committee:

Gerald Young (Advisor); Curtis Clemons (Advisor)

Subjects:

Geochemistry; Geology; Geophysics; Mathematics

Keywords:

Rimstone Dams; calcium precipitation; cave formations;asymptotic expansion;volumetric flow rate;coupled differential equations

Pepple, Chris CFactors Affecting the Precipitation of Quartz Under Hydrothermal Conditions
Master of Science (MS), Bowling Green State University, 2008, Geology
Natural Pocono Sandstone and synthetic quartz crystals, crushed and sieved (125-250um), have been used to experimentally evaluate changes in the rate and nature of quartz cementation under hydrothermal conditions. Experiments were carried out from 1 hour to 5 weeks at temperatures of 300-600°C and at 150 MPa confining pressure to simulate cementation conditions analogous to a quartz reservoir at depth. Experimental charges consisted of AlCl3, amorphous silica, NaCl brine, and one of the quartz sample materials weld-sealed in a gold tube. Interactions of quartz systems with and without the addition of iron oxides (goethite) were conducted to determine the influence of iron oxides on cementation. After the experiments, samples were impregnated with epoxy and then analyzed using cathodoluminescence (CL), plain polarized light (PPL), cross polarized light (XPL), and scanning electron microscopy (SEM). Mosaic images were constructed for node counting of grains, cement, and porosity for synthetic quartz samples, and grains and porosity measures for Pocono Sandstone experiments. The mosaic images illustrate precipitation and dissolution occurred at sample bases and tops due to a saturation gradient formed by the interactions of AlCl3 and amorphous silica. Measured cement and porosity values of synthetic quartz samples were used to calculate precipitation and transport rates detailing differences between pure and goethite system experiments. Consistently, synthetic quartz goethite experiments showed greater cementation in response to increased silica solubility and goethite’s pervasive and adsorptive nature towards quartz. In addition, it is shown that significant amounts of quartz cementation can occur due to saturation gradients between quartz and amorphous silica even in the absence of a temperature or pressure gradient.

Committee:

John Farver (Advisor)

Subjects:

Geochemistry; Geology

Keywords:

Pocono Sandstone; quartz; silica; cementation; precipitation; amorphous silica; goethite; cathodoluminescence

Moyer, Ryan P.Carbon Isotopes (δ13C & Δ14C) and Trace Elements (Ba, Mn, Y) in Small Mountainous Rivers and Coastal Coral Skeletons in Puerto Rico
Doctor of Philosophy, The Ohio State University, 2008, Geological Sciences
Tropical small mountainous rivers (SMRs) may transport up to 33% of the total carbon (C) delivered to the oceans. However, these fluxes are poorly quantified and historical records of land-ocean carbon delivery are rare. Corals have the potential to provide such records in the tropics because they are long-lived, draw on dissolved inorganic carbon (DIC) for calcification, and isotopic variations within their skeletons are useful proxies of palaeoceanographic variability. The ability to quantify riverine C inputs to the coastal ocean and understand how they have changed through time is critical to understanding global carbon budgets in the context of modern climate change. A seasonal dual isotope (13C & 14C) characterization of the three major C pools in two SMRs and their adjacent coastal waters within Puerto Rico was conducted in order to understand the isotope signature of DIC being delivered to the coastal oceans. Additionally a 56-year record of paired coral skeletal C isotopes (δ13C & Δ14C) and trace elements (Ba/Ca, Mn/Ca, Y/Ca) is presented from a coral growing ~1 km from the mouth of an SMR. Four major findings were observed: 1) Riverine DIC was more depleted in δ13C and Δ14C than seawater DIC, 2) the correlation of δ13C and Δ14C was the same in both coral skeleton and the DIC of the river and coastal waters, 3) Coral δ13C and Ba/Ca were annually coherent with river discharge, and 4) increases in coral Ba/Ca were synchronous with the timing of depletions of both δ13C and Δ14C in the coral skeleton and increases in river discharge. This study represents a first-order comprehensive C isotope analysis of major C pools being transported to the coastal ocean via tropical SMRs. The strong coherence between river discharge and coral δ13C and Ba/Ca, and the concurrent timing of increases in Ba/Ca with decreases in δ13C and Δ14C suggest that river discharge is simultaneously recorded by multiple geochemical records. Based on these findings, the development of coral-based proxies for the history of land-ocean carbon flux would be invaluable to understanding the role of tropical land-ocean carbon fluxes in the context of global climate change.

Committee:

Andrea Grottoli, PhD (Advisor); James Bauer, PhD (Committee Member); Anne Carey, PhD (Committee Member); Yu-Ping Chin, PhD (Committee Member); Matthew Saltzman, PhD (Committee Member)

Subjects:

Biogeochemistry; Geochemistry; Geology; Oceanography

Keywords:

Coral Biogeochemistry; Carbon Isotopes; Carbon Cycle; Land-Ocean Carbon Flux; Puerto Rico; Trace Elements; ICPMS

Khadka, Mitra B.Variation in Trace Metal Concentrations in A Fluvial Environment, Ottawa River, Toledo, Ohio
Master of Science (MS), Bowling Green State University, 2010, Geology
Surface sediment samples were collected from a 1000 m meander reach of the Ottawa River, Ohio and analyzed for trace metals (Zn, Pb, Sr, Mn, Cu, Cr, Co, Ba, Ti, Cd, and Hg) by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) to determine the local variability in their concentrations between geomorphic features. Eight metals (Zn, Pb, Sr, Mn, Cu, Cr, Co, and Ba) show significantly different concentrations between five fluvial geomorphic features namely, flood plains, point bars, lateral bars, pools, and riffles. Among the features, flood plains and lateral bars are places where flows are decelerated due to surface roughness and vegetation cover, promoting the deposition of fine-grained sediments and organic matter. Thus, flood plains and lateral bars consistently exhibit the highest metal concentrations. The lowest metal concentrations in point bars are attributed to relatively coarse-grained sediment and low organic matter content. The difference in mean metal concentration between flood plains and point bars ranges from 5 times for Co to 12.5 times for Pb. It was found that Zn, Sr, Mn, Cu, Cr, Co, and Ba are influenced by similar transport and interaction processes, and possibly have common sources, while Pb shows a weak to non-significant association with other metals indicating either a different mode of transport or separate anthropogenic sources. The concentrations of all metals in 89% of the samples are below the Threshold Effect Level (TEL) and the Probable Effect Level (PEL), and thus sediment contamination issues are to be minor concern in this section of the river. The finding that flood plains serve as sediment-associated metals sink can have important implications for monitoring and regulation, impact assessment, and remediation of contaminated sediments in metal contaminated section of the Ottawa River or for other rivers having similar geomorphological, hydrological, and sedmentological characters.

Committee:

Sheila J. Roberts (Advisor); James E Evans (Committee Member); Enrique Gomezdelcampo (Committee Member)

Subjects:

Earth; Environmental Science; Geochemistry; Geology; Hydrology

Keywords:

trace metal; fluvial geomorphology; sediment contamination; environment; ottawa river; flood plain

Goldschmid, Tanhum, 1941-Aqueous chemistry and precipitation of aluminum phosphate /
Doctor of Philosophy, The Ohio State University, 1975, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geochemistry

Keywords:

Phosphates;Water

Lux, Daniel R.Geochronology, geochemistry, and petrogenesis of basaltic rocks from the Western Cascades, Oregon /
Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geochemistry

Keywords:

Basalt;Geological time;Geochemistry;Petrogenesis

Morelli, Erica CPillars and Buttes: A Petrologic Comparison of Modern and Ancient Hydrocarbon Seep Rock
BA, Oberlin College, 2015, Geology
Purpose: Literature on the formation of authigenic rock at cold seeps focuses on the role of microbes in creating geochemically favorable environment for the precipitation of carbonate and barite minerals. Less understood is the pathway that lithified microbial patches of seafloor sediment follow to become rock formations that are identified in strata dating back to the Silurian. In this study I will compare Holocene seep rock from the Gulf of Mexico to Cretaceous carbonates that have been identified as seep rock. Through the study of rock in its early stages of formation to rock that has likely undergone multiple phases of diagenesis I aim to establish a hypothetical sequence of formation of the Cretaceous seep rocks.

Committee:

Karla Parsons-Hubbard (Advisor); Bruce Simonson (Committee Member); Kristin Dorfler (Committee Member); Russell Shapiro (Committee Member)

Subjects:

Geochemistry; Geological; Geology; Petrology

Keywords:

Cretaceous;seep;rocks;

Jian, HanAN EXPERIMENTAL INVESTIGATION OF TRACE ELEMENT PARTITIONING DURING CORE CRYSTALLIZATION
Doctor of Philosophy, Case Western Reserve University, 2016, Geological Sciences
Non-metallic “light” elements are important constituents of asteroidal and planetary cores and may have a strong effect on the partitioning behavior of trace elements. Planetary and asteroidal cores are thought to contain a wide range of non-metallic “light” elements, such as H, C, N, O, Si, P, and S. Each of these elements may either attract or repel trace elements, when dissolved in liquid or solid metal. However, the influences of some light elements, such as oxygen, have been studied very little, and the combined effects of multiple light elements on trace element partitioning have not been quantified. We investigated the partitioning behavior between solid metal and liquid phases and between immiscible liquid metal phases of more than 25 trace elements within the Fe-S-O-P system with varying concentrations of S, O, and P. The experiments were performed under 1 atm pressures and temperatures ranging from 1000°C to 1300°C. We also investigated trace element partitioning among solid phases in the Fe-S, Fe-S-C, Fe-S-P, and the Fe-S-P-C systems under sub-solidus conditions at 1 atm.

Committee:

Van Orman James (Advisor); Jing Zhicheng (Committee Member); Hauck Steven (Committee Member); Lacks Daniel (Committee Member)

Subjects:

Geochemistry; Geological

Kaltenberg, Eliza MariaNew Approaches in Measuring Sediment-Water-Macrobenthos Interactions
Doctor of Philosophy, Case Western Reserve University, 2016, Geological Sciences
Sediment is an important sink for many anthropogenic and naturally occurring contaminants in aquatic systems. Physical and biogeochemical processes near the sediment-water interface control the fate of these pollutants, which can be either buried and therefore removed from the system or returned to the water column and biosphere through a variety of processes. Sediment-water interactions are often further complicated by the presence of macrobenthos, which can both alter the physical and chemical conditions in the sediment and be affected by the presence of contaminants. This research investigated the influence of PCB pollution on the bioturbative behavior of Leptocheirus plumulosus. A significant decrease in the rate of particle and solute mixing, measured using radioactive tracers, was observed in New Bedford Harbor sediment contaminated with polychlorinated biphenyls (PCBs) and heavy metals, when compared to a control. Dose-response experiments revealed that the burrowing behavior of L. plumulosus was relatively unchanged up to about 60 mg PCB/kg d.w., above which a strong decrease in the mixing rate was observed. This work also explored the possibility of using non-toxic, fluorescent luminophores to measure 2-dimensional particle redistribution as a substitute for 1-dimensional measurements obtained with particle radiotracers. Good agreement between the two tracers was obtained for 4 marine/estuarine benthos with different styles of mixing, with the best agreement observed for the biodiffusive species. The 2-dimensional capability of the luminophore methodology helped determine whether uniform mixing assumption of the biodiffusive model, used for both tracers, was met. Finally, a new method for measuring the diffusive flux of phosphorus from sediment was developed. The method involves using Diffusive Equilibrium in Thin films (DET) to obtain high resolution overlying and pore water soluble reactive phosphorus (SRP; phosphate) concentrations. Two-dimensional SRP distribution maps were obtained by equilibrating sheets of polyacrylamide hydrogel with the surrounding pore and overlying water and then developing the color using standard colorimetric reagents. The gels were then scanned and digitized using a conventional flatbed scanner. Concentration gradients across the sediment-water were determined from the phosphate DET maps and used to calculate SRP fluxes based on Fick’s first law of diffusion.

Committee:

Gerald Matisoff, Dr. (Advisor)

Subjects:

Environmental Science; Geochemistry; Toxicology

Keywords:

bioturbation; sediment; biodiffusion coefficient; burial velocity; sublethal toxicity; behavioral response; macrobenthos; amphipod; bivalve; polychaete; DET; phosphorus flux; Leptocheirus plumulosus

Fair, Alexandria CElemental Cycling in a Flow-Through Lake in the McMurdo Dry Valleys, Antarctica: Lake Miers
Master of Science, The Ohio State University, 2014, Earth Sciences
The ice-free area in Antarctica known as the McMurdo Dry Valleys has been monitored biologically, meteorologically, hydrologically, and geochemically continuously since the onset of the MCM-LTER in 1993. This area contains a functioning ecosystem living in an extremely delicate environment. Only a few degrees of difference in air temperature can effect on the hydrologic system, making it a prime area to study ongoing climate change. The unique hydrology of Lake Miers, i.e. its flow- through nature, makes it an ideal candidate to study the mass balance of a McMurdo Dry Valley lake because both input and output concentrations can be analyzed. This study seeks to understand the physical and geochemical hydrology of Lake Miers relative to other MCMDV lakes. Samples were collected from the two inflowing streams, the outflowing stream, and the lake itself at 11 depths to analyze a suite of major cations (Li+, Na+, K+, Mg+, Ca2+), major anions (Cl-, Br-, F-, SO42-, ΣCO2), nutrients (NO2-, NO3-, NH4+, PO43-, Si), trace elements (Mo, Rb, Sr, Ba, U, V, Cu, As), water isotopes (δD, δ18O), and dissolved organic carbon (DOC). The lake acts as a sink for all constituents analyzed, but by amounts varying from ~10% (DOC, NH4+, and NO2-) to PO43- at nearly 100%, indicating this lake may be P-limited. Cl-, a typically conservative element, was only 79% retained, which could be due to the late season sample collection, hyperheic zone influences, or other factors. The hyperheic zone’s role in lake and stream geochemistry was analyzed with a 24-hour sampling event. The positive relationships between stream flow and solute concentrations indicate that the delta in Miers Valley plays a role in controlling stream geochemistry and future work could help to explain this relationship. Lake depth profiles of trace elements U, V, Cu, and As decrease relative to Cl in the deepest part of the lake, while non-reducing trace elements show increases with depth. SO42- and dissolved O2 lake depth profiles decrease from 53 µM and 22.3 mg/L to 18 µM and 1.8 mg/L, respectively, at depth, indicating that the lake bottom is under reducing and near anoxic conditions. Lake depth profiles show that, while the “biological pump” may be a factor controlling lake chemistry, it is masked by the stronger signal of diffusion from the lake bottom sediments and requires future work to understand fully. The “age” of Lake Miers was calculated with a diffusion model to be 84 years, which agrees with other estimates of 100-300 years. The diffusion of solutes from the lake bottom and the redox conditions at depth are two major processes controlling the geochemistry of Lake Miers, and future work can help determine their extent and relationship with other processes.

Committee:

William Lyons (Advisor); Anne Carey (Committee Member); Yu-Ping Chin (Committee Member)

Subjects:

Geochemistry; Geology

Keywords:

geochemistry, McMurdo Dry Valleys, Lake Miers

Freese, Kevin MAssessment of Sulfate in Ohio Transportation Subgrades
Master of Science in Engineering, University of Akron, 2014, Civil Engineering
The Ohio Department of Transportation (ODOT) recently implemented global chemical stabilization for new construction or repair involving major road projects. Pavement heave caused the failure of the road surfaces in three projects in Lake County, Ohio. Subsequent soil investigation revealed surface heave was caused by soil swell from the formation of a calcium alumina sulfate hydrate, ettringite (Ca6Al2(SO4)3(OH)12•26H2O) which may occur in sulfate bearing soils chemically stabilized with lime. Failure of pavement in these three projects caused ODOT to question the whether other regions within Ohio had subgrades with high soluble sulfate concentrations. This report is an investigation into natural and anthropogenic sources of sulfate (SO4) in Ohio soils evaluated via literature review and soil testing. The ODOT provided just under 350 soil samples from 39 different counties throughout the state for assessment of soil chemistry and mineralogy. Soluble SO4, often the primary controlling factor in degree of ettringite formation, was measured within soils using colorimetric methods. Several soils were additionally tested for total metal (Al, Fe and Cr) concentrations using acid digestion and inter coupled plasma optical emissions spectrometry (ICP-OES). Total Al concentration within soils was analyzed, as Al and SO4 are the chemicals within ettringite which have their primary source as the prestabilized soil. Total Fe was assessed as a marker for potential areas where sulfate would have formed from the oxidation of pyrite (FeS2). Total Cr concentration was tested as chromate (CrO4) can be a replacement group for SO4 within the ettringite structure. Additionally initial review of literature identified chromite ore processing residue remediation as a potential source of excess SO4 in soils. Finally, soil mineralogy was analyzed via x-ray diffraction (XRD). Results indicate Lake County, Ohio is not the only region with Ohio where ODOT should expect subgrades with problematic soluble SO4 concentrations. Although further soil testing throughout the state is needed, sufficient sulfate concentration (>3,000 mg/kg) for elevated risk of sulfate-induced heave were identified in a number of soils and three key regions within Ohio: Lake County in the northeast, Paulding and Defiance counties in the northwest and Morrow County in the north central. Within both Lake County soils and the Paulding and Defiance area soils, the primary identified SO4 bearing minerals were evaporates, gypsum and anhydrite. The natural origin of these mineral is most likely glacial lacustrine deposits. However, there are anthropogenic sources which likely add SO4 to soils within these regions. The high degree of industrial activities including coal fired power plants add SO4 to soil in Lake County. Whereas the application of gypsum as a farmland amendment is the likely anthropogenic source in Paulding and Defiance counties. Gypsum and pyrite were identified as the primary and secondary sulfur bearing minerals, respectively, in Morrow County soils. The origin of pyrite within this region is from Devonian Shale bedrock. The oxidation of these pyritic shales was identified as the primary source of SO4, in the form of gypsum, in Morrow County soils.

Committee:

Teresa Cutright, Dr (Advisor); John Senko, Dr (Committee Member); Ala Abbas, Dr (Committee Member)

Subjects:

Civil Engineering; Environmental Engineering; Geochemistry; Geotechnology; Transportation

Keywords:

Sulfate; Soil Heave; Ettringite; Soil Swell; Subgrade; Gypsum; Pyrite; Lime Stabilization; Soluble Sulfate; Total Metal Concentration

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