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2017

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Articles 31 - 60 of 98

Full-Text Articles in Geochemistry

Urban Detention Basin Contamination With Polycyclic Aromatic Hydrocarbons (Pahs) And Metals, Holly Marie Duff Aug 2017

Urban Detention Basin Contamination With Polycyclic Aromatic Hydrocarbons (Pahs) And Metals, Holly Marie Duff

Graduate Theses/Dissertations

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds that can be toxic to wildlife and humans when released to the environment. Coal-tar sealants, which are applied to parking lots or driveways, contribute up to 1,000 times more PAHs than alternative sealants. Over time, these sealants abrade and are transported into drainage networks. Coal-tar sealants are currently used in Springfield, Missouri, however the extent of PAH contamination throughout urban drainage systems is unclear. This study focused on PAH contamination within an urban detention basin on the Missouri State University campus which receives runoff from several coal-tar sealed parking lots. Sediment samples collected …


New Biotite And Muscovite Isotopic Reference Materials, Usgs57 And Usgs58, For Δ2h Measurements–A Replacement For Nbs 30, Haiping Qi, Tyler B. Coplen, Matthias Gehre, Torsten W. Vennemann, Willi A. Brand, Heike Geilmann, Gerald Olack, Ilya N. Bindeman, Jim Palandri, Li Huang, Fred J. Longstaffe Jul 2017

New Biotite And Muscovite Isotopic Reference Materials, Usgs57 And Usgs58, For Δ2h Measurements–A Replacement For Nbs 30, Haiping Qi, Tyler B. Coplen, Matthias Gehre, Torsten W. Vennemann, Willi A. Brand, Heike Geilmann, Gerald Olack, Ilya N. Bindeman, Jim Palandri, Li Huang, Fred J. Longstaffe

Earth Sciences Publications

The advent of continuous-flow isotope-ratio mass spectrometry (CF-IRMS) coupled with a high temperature conversion (HTC) system enabled faster, more cost effective, and more precise δ2H analysis of hydrogen-bearing solids. Accurate hydrogen isotopic analysis by on-line or off-line techniques requires appropriate isotopic reference materials (RMs). A strategy of two-point calibrations spanning δ2H range of the unknowns using two RMs is recommended. Unfortunately, the supply of the previously widely used isotopic RM, NBS 30 biotite, is exhausted. In addition, recent measurements have shown that the determination of δ2H values of NBS 30 biotite on the VSMOW-SLAP …


Geochemistry Of Volatiles Released By Incipient Continental Rifting And Subduction Processes, Hyunwoo Lee Jul 2017

Geochemistry Of Volatiles Released By Incipient Continental Rifting And Subduction Processes, Hyunwoo Lee

Earth and Planetary Sciences ETDs

Volatiles (N2, CO2, and He) are released by volcanism and hydrothermal activity during continental rifting and subduction processes. Analyses of volatile components have been conducted to obtain gas contents (CO2, SO2, H2S, N2, Ar, He, and so on), stable isotope compositions (δ13C, δ15N, and so on), and noble gas isotopes (3He/4He, 40Ar/36Ar, and so on). This dissertation includes four chapters to report new nitrogen isotope fractionation factors of bubbling gases during gas-water transfer at various water temperatures (Chapter 1), first measurements of massive amounts of CO2 released by incipient continental rifting in the Magadi and Natron Basin, East African Rift …


Nuclear Weapons In A Changing Climate: Probability, Increasing Risks, And Perception, Adam Liska, Tyler R. White, Eric Holley, Robert J. Oglesby Jul 2017

Nuclear Weapons In A Changing Climate: Probability, Increasing Risks, And Perception, Adam Liska, Tyler R. White, Eric Holley, Robert J. Oglesby

Adam Liska Papers

Many people tend to think that the outcome of any nuclear weapons use today will result in an escalatory situation with apocalyptic outcomes for the countries involved. Yet many factors are increasing the probability of the limited use of nuclear weapons (e.g., 1 to 20 warheads) in a range of conflict scenarios. Previous atmospheric model simulations of regional nuclear conflicts employing many relatively small bombs have been estimated to cause a global “nuclear autumn,” with great reductions in agricultural productivity, stratospheric ozone loss, and spread of hazardous radioactive fallout. The totality of these effects would result in widespread damage …


Measuring Inorganic Carbon Fluxes From Carbonate Mineral Weathering From Large River Basins: The Ohio River Basin, Autumn B. Singer Jul 2017

Measuring Inorganic Carbon Fluxes From Carbonate Mineral Weathering From Large River Basins: The Ohio River Basin, Autumn B. Singer

Masters Theses & Specialist Projects

Rising atmospheric CO2 concentrations have motivated efforts to better quantify reservoirs and fluxes of Earth’s carbon. Of these fluxes from the atmosphere, one that has received relatively little attention is the atmospheric carbon sink associated with carbonate mineral dissolution. Osterhoudt (2014) and Salley (2016) explored new normalization techniques to improve and standardize a process for measuring this flux over large river basins. The present research extends this work to the 490,600 km2 Ohio River drainage basin and 11 subbasins. The study estimated the DIC flux leaving these basins between October 1, 2013, and September 30, 2014, based on secondary hydrogeochemical, …


Biogeochemical Interactions In Flooded Underground Mines, Renee Schmidt Jul 2017

Biogeochemical Interactions In Flooded Underground Mines, Renee Schmidt

Graduate Theses & Non-Theses

This study presents a biogeochemical analysis of microbial communities in flooded underground mines in Butte, Montana, USA. Samples were collected from nine mineshafts representing three distinct geochemical zones. These zones consist of the East, West, and Outer Camp mines. The East Camp mines, bordering the Berkeley Pit Superfund site, have the highest concentrations of dissolved metals and the most acidic pH values. Dissolved metal concentrations in the West Camp are one to three orders of magnitude lower than in the East Camp and have nearly neutral pH values. The Outer Camp mines have similar metal concentrations to the West Camp …


Tracking Potential Leakage Of Tailings-Lake Water Into Background Groundwater In Butte, Montana, Using Geochemical And Stable Isotope Tracers, Matthew Berzel Jul 2017

Tracking Potential Leakage Of Tailings-Lake Water Into Background Groundwater In Butte, Montana, Using Geochemical And Stable Isotope Tracers, Matthew Berzel

Graduate Theses & Non-Theses

This study was conducted to identify environmental tracers using water chemistry and stable isotopes in the Moulton Road area adjacent to the Yankee Doodle tailings impoundment north of Butte, Montana. The water level of the tailings lake is being raised as tailings slurry is pumped up to the impoundment, and numerous residential wells are located in close proximity. Although it has an alkaline pH (> 9), the water in the tailings lake is much higher in some chemical constituents than the wells and some of these constituents could be used as tracers to determine if lake water is migrating out …


Foundations For A Geobiochemical Characterization Of Mudpots In Yellowstone National Park, Georgia Dahlquist Jul 2017

Foundations For A Geobiochemical Characterization Of Mudpots In Yellowstone National Park, Georgia Dahlquist

Graduate Theses & Non-Theses

Mudpots are acidic, turbid thermal features formed by the argillic or sericitic alteration of rock with enough fluid to create a viscous feature. Prior to this research, the combination of interdisciplinary sampling for geochemistry, mineralogy, and microbiology of rhyolite hosted mudpots, particularly in chemically distinct subregions of an area, remained largely unavailable. This work discusses mudpots and nearby hot springs sampled in Yellowstone National Park (YNP) in July 2016 and the measured in situ pH, temperature, and conductivity values, and dissolved oxygen concentrations. Water, filtered via gravity pre-filtration and 1.2 μm and 0.8/0.2μm syringe filtration, yielded δD and δ18O values …


Mineral Evidence For Generating Compositionally Zoned Rhyolites Of The Devine Canyon Tuff, High Lava Plains, Oregon, Erik Paul Shafer Jun 2017

Mineral Evidence For Generating Compositionally Zoned Rhyolites Of The Devine Canyon Tuff, High Lava Plains, Oregon, Erik Paul Shafer

Dissertations and Theses

Large-volume silicic eruptions are often evacuated from magma reservoirs which display gradients in composition, temperature, crystallinity, and volatile content. The 9.7 Ma Devine Canyon Tuff (DCT) of eastern Oregon represents such an eruption, with >300 km³ of compositionally zoned pyroclastic material deposited as a variably-welded ignimbrite. The ignimbrite displays homogenous bulk tuff major element compositions with a wide range of trace element compositions, allowing for the investigation of how these magmas were generated, stored, and modified in the magma reservoir by studying pumices which represent the primary magmas composing the DCT. Five pumices ranging from dacite to rhyolite bulk compositions …


Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca Jun 2017

Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca

Civil Engineering ETDs

Cooling towers, integrated circuit (IC) manufacture and reverse osmosis (RO) generate copious amounts of wastewater high in colloidal and reactive silica inhibiting on-site or synergistic reuse. Silica present in cooling water can reach solubility limits via evaporation and form impervious scale on heat transfer surfaces that decreases efficiency. When water is treated by RO operating at high rejection, silica forms difficult-to-remove scale on the membrane feed side in the form of glassy patches and communities of aggregate particles, inhibiting aspirations for zero liquid discharge. Current methods for silica scale mitigation include abundant dosing with chemical antiscalents or complex operating schemes. …


The Effect Of Diffusive Transport On Mineral Carbonation In Geologic Carbon Sequestration, Wei Xiong May 2017

The Effect Of Diffusive Transport On Mineral Carbonation In Geologic Carbon Sequestration, Wei Xiong

McKelvey School of Engineering Graduate Student Theses & Dissertations

Geologic carbon sequestration (GCS) is an effective method to mitigate environmental problems due to excessive anthropogenic CO2 emissions. It involves injecting supercritical CO2 into deep geologic formations in which CO2 will ultimately be converted to solid carbonate minerals. Basalt is a promising host rock that is rich in the divalent cations Ca, Mg and Fe that are important for mineral trapping of CO2. Fractures and pores in basalt reservoirs provide substantial surface area for geochemical reactions during carbon sequestration. The transport in fractures and pores is controlled by diffusion. The coupling of diffusive transport and geochemical reactions leads to carbonate …


Geochemical And Petrographic Analysis Of Basaltic Rocks Of The Hawaiian Island: Implications For Their Evolutionary Stage Of Development, Autumn A. Burrell May 2017

Geochemical And Petrographic Analysis Of Basaltic Rocks Of The Hawaiian Island: Implications For Their Evolutionary Stage Of Development, Autumn A. Burrell

Honors Program Theses and Projects

Geochemical and petrographic analyses of basaltic rocks were performed from five volcanoes on the Big Island of Hawaii. From north to south these volcanoes include: Kohala; Hualalai; Mauna Kea; Mauna Loa; and Kilauea. These volcanoes have formed through several distinct stages of volcanic growth and development. During each of these stages, the lavas extruded will be composed of a distinctive geochemical signature which corresponds to each of the 4 main phases of development. These include a 1) pre-shield building; 2) main shield building; 3) post-shield building; and 4) a rejuvenated stage.

The geochemical results are used to establish the evolutionary …


Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, Zoltan Vaci May 2017

Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, Zoltan Vaci

Earth and Planetary Sciences ETDs

The Martian olivine-phyric basalt Northwest Africa (NWA) 10416 contains large olivine xenocrysts whose cores have been stained brown by hydrothermal alteration and whose rims are composed of pristine olivine overgrowths. Microanalysis of these olivine cores reveals various degrees of amorphization, some of which have been overprinted by terrestrial weathering, evident as part of a weathering rind along the exposed surface of the meteorite. Studies of a completely unweathered terrestrial analogue basalt from southern Colorado reveal similar features and indicate that both basalts were altered in a supersolidus magma chamber setting. The alteration features in NWA 10416 thus imply the presence …


Petrography And Geochemistry Of Oligocene Rhyolitic Volcanic Rocks, Western Mogollon-Datil Volcanic Field, New Mexico, Emily Elizabeth Salings May 2017

Petrography And Geochemistry Of Oligocene Rhyolitic Volcanic Rocks, Western Mogollon-Datil Volcanic Field, New Mexico, Emily Elizabeth Salings

Graduate Theses/Dissertations

The Mogollon-Datil volcanic field (MDVF), located in southern New Mexico, is the remnant of extreme and punctuated volcanism over ~12 m.y. of activity. The Bursum caldera is the youngest of three nested calderas in the Mogollon Mountains in the western MDVF. Here I present data from a high-silica, large volume tuff associated with the Bursum caldera, the Bloodgood Canyon Tuff (BCT). Extensive mapping by previous workers have provided a limited whole rock geochemical dataset and descriptions of the unit, but a detailed study had not been conducted. I present new whole-rock major- and trace-element analyses, Sr, Nd, and Pb isotope …


Geochronology Of The Tectonic, Stratigraphic, And Magmatic Evolution Of Neoproterozoic To Early Paleozoic, North American Cordillera And Cryogenian Glaciation, Vincent H. Isakson May 2017

Geochronology Of The Tectonic, Stratigraphic, And Magmatic Evolution Of Neoproterozoic To Early Paleozoic, North American Cordillera And Cryogenian Glaciation, Vincent H. Isakson

Boise State University Theses and Dissertations

Neoproterozoic sedimentary successions contain evidence for some of the most extreme climate fluctuations, breakup of the paleo-supercontinent Rodina, multiple low-latitude global glaciations, and the resultant evolution and radiation of complex life. The stratigraphic record of these events are found on all major continents and have been associated with, in part, global ‘Snowball Earth’ events. However, the understanding and integration of these, and related phenomenon, are limited by disparate and imprecise age constraints that prohibit clear correlation between locations.

This research focused on high-precision geochronology within an integrated framework of sedimentology, stratigraphy, and geochemistry to resolve the timing and duration of …


Phosphate Release: The Effect Of Prebiotic Organic Compounds On Dissolution Of Merrillite, Whitlockite, Chlorapatite, And Fluorapatite, Courtney Lea Bartlett May 2017

Phosphate Release: The Effect Of Prebiotic Organic Compounds On Dissolution Of Merrillite, Whitlockite, Chlorapatite, And Fluorapatite, Courtney Lea Bartlett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Phosphate is an essential nutrient on Earth, used by life for ATP, DNA, RNA, and phospholipid membranes. Therefore, if life is or ever was present on Mars, phosphorus may have played an important role in determining the habitability of an environment. Phosphorus does not have a significant volatile phase; its release from minerals is consequently critical to phosphorus availability and prebiotic chemistry. Phosphate release from Mars-relevant minerals such as merrillite and chlorapatite has been previously found to differ significantly from phosphate release from fluorapatite, the dominant phosphate phase on Earth. However, the environments in which phosphate release would have been …


Cyclostratigraphic Trends Of Δ13c In Upper Cambrian Strata, Great Basin, Usa: Implications For Astronomical Forcing, Wesley Donald Weichert May 2017

Cyclostratigraphic Trends Of Δ13c In Upper Cambrian Strata, Great Basin, Usa: Implications For Astronomical Forcing, Wesley Donald Weichert

Graduate Theses/Dissertations

Composite geochemical studies of carbonate isotope values (δ13C) by other investigators have established that the Cambrian period is punctuated by a series of significant, globally correlated, positive and negative δ13C excursions. However, it remains unclear if low-amplitude secular variations in δ13C values exist superimposed on, or between large-scale perturbations in the Cambrian carbon cycle, especially in cyclic successions. Rocks of Steptoean-Sunwaptan (Paibian-Jiangshanian) stage, exposed in the Great Basin of Utah and Nevada, are excellent candidates for testing the hypothesis that sedimentary cycles record minor variations in Earth's orbit (Milankovitch cycles) through application of high-resolution chemostratigraphic analysis. High-resolution δ13C data was …


Geochronology Of Calc-Alkaline Ash Flow Tuff Units In The Ogollon Datil Volcanic Field, Southern New Mexico: U-Pb In Zircon, Shannon Porter Rentz May 2017

Geochronology Of Calc-Alkaline Ash Flow Tuff Units In The Ogollon Datil Volcanic Field, Southern New Mexico: U-Pb In Zircon, Shannon Porter Rentz

Graduate Theses/Dissertations

Caldera systems are capable of outputting voluminous quantities of volcaniclastic material with wide ranging negative environmental impacts. Determining the behaviors of previously erupted caldera systems may help inform predictive models used to evaluate hazards and assess risks for analogous currently active volcanic systems. The Mogollon-Datil volcanic field (MDVF) is a 40-24 Ma cluster of caldera activity in southern New Mexico tied to the subduction, and possible delamination, of the Farallon plate beneath the North American plate. A regional ignimbrite flare up from 36-24 Ma produced at least 28 caldera-forming eruptions. The calc-alkaline magmatism of three calderas in this field (the …


Depositional Dynamics Of The Upper Eagle Ford (Upper Cretaceous): Karnes And Gonzales Counties, South Texas, Josie Brunick May 2017

Depositional Dynamics Of The Upper Eagle Ford (Upper Cretaceous): Karnes And Gonzales Counties, South Texas, Josie Brunick

Graduate Theses and Dissertations

The mixed siliciclastic/carbonate late Cretaceous Eagle Ford Formation is commonly divided into the lower Eagle Ford and the upper Eagle Ford. The lower Eagle Ford is arguably the most obvious organic rich interval highlighted with wireline log data; however, the upper Eagle Ford may have just as much potential for hydrocarbon production success as the lower Eagle Ford has had. A better understanding of the upper Eagle Ford will allow a more thorough and educated assessment into its full potential as an unconventional reservoir, and allow its sweet spots for oil or gas to be found and exploited.

This study …


Hydrocarbon And Co2 Emissions From Oil And Gas Production Well Pad Soils Comparative To Background Soil Emissions In Eastern Utah, Cody S. Watkins May 2017

Hydrocarbon And Co2 Emissions From Oil And Gas Production Well Pad Soils Comparative To Background Soil Emissions In Eastern Utah, Cody S. Watkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

What effect does the development of oil and gas have on the observed air quality (i.e., increased ozone, carbon dioxide (CO2), volatile organic compounds (VOCs), and/or methane emissions) in northeastern Utah? What percentage of these gases is natural background emissions, and what percentage is due to the recent oil and gas development in the region? Emissions in this text refer to gases released from the earth’s surface to the atmosphere. Methane is the primary compound in natural gas. Natural gas is a naturally occurring hydrocarbon gas mixture. Emissions of methane, non-methane hydrocarbons (NMHC), and CO2 at 27 …


An Elemental Highway: Investigation Of A High Nickel Anomaly In Olivine From The Island Of Niihau, Hawaii, Alexander James Valentine May 2017

An Elemental Highway: Investigation Of A High Nickel Anomaly In Olivine From The Island Of Niihau, Hawaii, Alexander James Valentine

UNLV Theses, Dissertations, Professional Papers, and Capstones

The study of volcanic geochemistry is one of the main gateways for investigating the Earth’s mantle. One important topic in the field is that of nickel (Ni) in the mineral olivine. While Ni is a compatible element in olivine, its high concentration at a given MgO content is not well understood. A variety of hypotheses have been proposed, including attributing presence of Ni to pyroxenite source melting, contribution from the core, or variation in peridotite source melting. In addition to the other hypotheses, chemical diffusion may also be a mechanism for enriching olivine Ni concentration. Magnesium-iron (Mg-Fe) isotopic measurements have …


Timing Of Speleogenesis Of Las Karmidas Cave (Mexico): First Description Of Pseudokarst Developed In Ignimbrite, María Del Pilar Aliaga-Campuzano, Rafael López-Martínez, Pablo Dávila-Harris, Ramón Espinasa-Pereña, Adriana Espino Del Castillo, J.P. Bernal Apr 2017

Timing Of Speleogenesis Of Las Karmidas Cave (Mexico): First Description Of Pseudokarst Developed In Ignimbrite, María Del Pilar Aliaga-Campuzano, Rafael López-Martínez, Pablo Dávila-Harris, Ramón Espinasa-Pereña, Adriana Espino Del Castillo, J.P. Bernal

International Journal of Speleology

Las Karmidas Cave (Puebla State, Mexico) is an unusual type of pseudokarstic cavity generated by piping and erosive processes within the contact of a diamicton and an overlying Quaternary ignimbrite. Morphological evidence suggests that the cave was developed in two stages: a phreatic stage and a vadose stage. The latter was characterized by the formation of carbonate speleothems. The absolute upper-age limit for the cave (168 +7.1/-7.5 ka) was established by U-Th dating of zircons grains extracted from the overlying ignimbrite, whilst a minimum age for the transition from a phreatic to vadose regime (95.6 ± 2.1 ka) was constrained …


Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali Apr 2017

Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali

Chemistry Faculty Publications

How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence …


Mineralogy And Geochemistry Of The Heddleston Porphyry Cu-Mo Deposit, Montana, Ben Schubert Apr 2017

Mineralogy And Geochemistry Of The Heddleston Porphyry Cu-Mo Deposit, Montana, Ben Schubert

Graduate Theses & Non-Theses

The Heddleston porphyry Cu-Mo deposit is located in Lewis and Clark County, Montana, near the headwaters of the Blackfoot River. It is immediately west of the historic Mike Horse mine, an important producer of Pb-Zn from polymetallic veins and lodes. The Heddleston property was explored extensively by the Anaconda Company in the 1960s and 1970s, but was never mined. Specimens of polished drill core from the deposit are archived in the Anaconda Research Collection at Montana Tech campus. The purpose of this research project was to use the archived samples to examine the geochemistry and mineralogy of the Heddleston and …


Supergene Mineralization Of The Continental Pit, Butte, Silver Bow County, Montana, Kyle Eastman Apr 2017

Supergene Mineralization Of The Continental Pit, Butte, Silver Bow County, Montana, Kyle Eastman

Graduate Theses & Non-Theses

The Butte porphyry Cu-Mo-Ag deposit has been considerably altered by supergene processes that enriched Cu and Ag, and mobilized other metals. Supergene enrichment provided early miners with excellent ore grades, and contributes significantly to current mining operations in Butte. The Continental Pit exhibits the classic leached and enriched vertical zonation that is common in near-surface porphyry systems around the world. Although studied by the Anaconda Copper Mining Company during the mid-20th century, significant and economically relevant questions remain regarding this deposit’s supergene heavy metal geochemistry and its relationship to the local hydrology and tectonic history.

This thesis investigates the paragenesis …


Actively Forming Kuroko-Type Volcanic-Hosted Massive Sulfide (Vhms) Mineralization At Iheya North, Okinawa Trough, Japan, Christopher J. Yeats, Steven P. Hollis, Angela Halfpenny, Juan-Carlos Corona, Crystal Laflamme, Gordon Southam, Marco Fiorentini, Richard J. Herrington, John Spratt Apr 2017

Actively Forming Kuroko-Type Volcanic-Hosted Massive Sulfide (Vhms) Mineralization At Iheya North, Okinawa Trough, Japan, Christopher J. Yeats, Steven P. Hollis, Angela Halfpenny, Juan-Carlos Corona, Crystal Laflamme, Gordon Southam, Marco Fiorentini, Richard J. Herrington, John Spratt

All Faculty Scholarship for the College of the Sciences

Modern seafloor hydrothermal systems provide important insights into the formation and discovery of ancient volcanic-hosted massive sulfide (VHMS) deposits. In 2010, Integrated Ocean Drilling Program (IODP) Expedition 331 drilled five sites in the Iheya North hydrothermal field in the middle Okinawa Trough back-arc basin, Japan. Hydrothermal alteration and sulfide mineralization is hosted in a geologically complex, mixed sequence of coarse pumiceous volcaniclastic and fine hemipelagic sediments, overlying a dacitic to rhyolitic volcanic substrate. At site C0016, located adjacent to the foot of the actively venting North Big Chimney massive sulfide mound, massive sphalerite-(pyrite-chalcopyrite ± galena)-rich sulfides were intersected (to 30.2% …


Alicyclic And Aromatic Carboxylic Acids In Soil Organic Matter: An Investigation Of Potential Origin And Association With Plutonium Using Advanced Analytical Techniques, Nicole Didonato Apr 2017

Alicyclic And Aromatic Carboxylic Acids In Soil Organic Matter: An Investigation Of Potential Origin And Association With Plutonium Using Advanced Analytical Techniques, Nicole Didonato

Chemistry & Biochemistry Theses & Dissertations

Carboxylic acids are a defining component of soil organic matter, responsible for many of the physical and chemical properties, including metal-organic matter interactions, which govern its role as an important constituent of soils. However, there is a shortage of detailed molecular level information regarding orientation and structural arrangement of carboxylic acids within soil organic matter. This dissertation utilizes electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) as well as solid-state and multi-dimensional nuclear magnetic resonance (NMR) to investigate the molecular formula composition within several organic matter sources and the primary structures that feature carboxylic acids. Soil organic matter …


Quantity Trumps Quality: Bayesian Statistical Accumulation Modeling Guides Radiocarbon Measurements To Construct A Chronology In Real-Time, Devon Robert Firesinger Mar 2017

Quantity Trumps Quality: Bayesian Statistical Accumulation Modeling Guides Radiocarbon Measurements To Construct A Chronology In Real-Time, Devon Robert Firesinger

USF Tampa Graduate Theses and Dissertations

The development of an accurate and precise geochronology is imperative to understanding archives containing information about Earth’s past. Unable to date all intervals of an archive, researchers use methods of interpolation to approximate age between dates. Sections of the radiocarbon calibration curve can induce larger chronological uncertainty independent of instrumental precision, meaning even a precise date may carry inflated error in its calibration to a calendar age. Methods of interpolation range from step-wise linear regression to, most recently, Bayesian statistical models. These employ prior knowledge of accumulation rate to provide a more informed interpolation between neighboring dates. This study uses …


Characterizing The Evolution Of Slab Inputs In The Earliest Stages Of Subduction: Preliminary Evidence From The Fluid-Mobile Element (B, Cs, As, Li) Systematics Of Izu-Bonin Boninitic Glasses Recovered During Iodp Expedition 352, Keir Aavon Sanatan Mar 2017

Characterizing The Evolution Of Slab Inputs In The Earliest Stages Of Subduction: Preliminary Evidence From The Fluid-Mobile Element (B, Cs, As, Li) Systematics Of Izu-Bonin Boninitic Glasses Recovered During Iodp Expedition 352, Keir Aavon Sanatan

USF Tampa Graduate Theses and Dissertations

Fluid-mobile elements (FMEs) such as B, Cs, As, Li and Tl can mobilize readily under low P-T conditions (0.2-0.5 GPa). This makes them effective geochemical tracers that can be used as a way of tracking fluid-rock exchanges at the shallow depths encountered in the earliest stages of subduction.

The Izu-Bonin-Mariana (IBM) subduction system is unique in that it preserves a record of the sequences produced from the onset of subduction through the development of arc magmatism. International Ocean Discovery Program (IODP) Expedition 352 recovered >800m of boninite core material from the earliest IBM magmatic events.

Select boninitic glasses from these …


Dependence Of The Martian Radiation Environment On Atmospheric Depth: Modeling And Measurement, Jingnan Guo, Tony C. Slaba, Cary Zeitlin, Robert F. Wimmer-Schweingruber, Francis F. Badavi, Eckart Böhm, Stephan Böttcher, David E. Brinza, Bent Ehresmann, Donald M. Hassler Feb 2017

Dependence Of The Martian Radiation Environment On Atmospheric Depth: Modeling And Measurement, Jingnan Guo, Tony C. Slaba, Cary Zeitlin, Robert F. Wimmer-Schweingruber, Francis F. Badavi, Eckart Böhm, Stephan Böttcher, David E. Brinza, Bent Ehresmann, Donald M. Hassler

Physics Faculty Publications

The energetic particle environment on the Martian surface is influenced by solar and heliospheric modulation and changes in the local atmospheric pressure (or column depth). The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory rover Curiosity on the surface of Mars has been measuring this effect for over four Earth years (about two Martian years). The anticorrelation between the recorded surface Galactic Cosmic Ray-induced dose rates and pressure changes has been investigated by Rafkin et al. (2014) and the long-term solar modulation has also been empirically analyzed and modeled by Guo et al. (2015). This paper employs the …