Geochemistry Commons^™

The Environmental Effects Of Coal Fires, Trent Garrison

Theses and Dissertations--Earth and Environmental Sciences

There are thousands of subterranean coal fires in the world that, because of incomplete combustion, emit a wide variety of volatile and semivolatile organic compounds to the atmosphere, water, and soil at concentrations that could pose health risks to humans and wildlife. The main goals of this study were to (1) review methods that are used to characterize physical and chemical characteristics of coal-fire sites, (2) determine relationships between gas emissions and physical and chemical characteristics of coal-fire sites, using a combination of regression and multivariate statistical methods, and (3) determine the concentrations of volatile and semivolatile organic compounds in …

Fluvial Responses To Growth Faulting In The West Pearl River, Louisiana, Stephen A. Prosser

Theses and Dissertations--Earth and Environmental Sciences

The Pearl River Delta (PRD) in southeastern Louisiana is an actively deforming deltaic complex displaying surface and near-surface evidence of growth faulting. Active growth faults in these environments are rarely identified at the surface, in part because the downthrown blocks often experience increased rates of sediment deposition leading to an obscured and low-relief, or entirely absent, surface expression. Faulting can be expressed in fluvial systems as changes in channel gradient, which often result in coincident changes in channel sinuosity, migration rates, planform deflections, and/or ponding features within the deformed zone. The study area is focused on a meander bend of …

A Geochemical Investigation Of Co₂ Sequestration And Site Characterization At Two Missouri Locations, Robert Allen Swain

Masters Theses

"The feasibility of sequestering CO₂ in saline aquifers of Lamotte Formation sandstone was investigated at wells located near Thomas Hill power plant, Moberly, MO and Sioux City Power Plant in Florissant, MO. Governing factors of using aquifers for CO₂ disposal include water salinity, potential for carbonic acid buffering, rate of precipitation of carbonate minerals following CO₂ introduction into the host aquifer, and the integrity of the Davis and Derby-DoeRun shale as a trap rock to prevent migration of the CO₂ phase and carbonic acid into the overlying potable Ozark Aquifer.

Both in situ and laboratory methods …

Timing And Source Of Alkali Enrichment At Mt. Etna, Sicily: Constraints From Clinopyroxene Geobarometry And In Situ Sr Isotope Data, Kaitlyn Nelson

All Master's Theses

Since 1971, Mt. Etna, Europe’s largest and most active volcano, has exhibited increased eruption frequency and explosivity. Associated with this increased activity, researchers have documented higher abundances of alkali elements (K, Rb, Cs) as well as elevated ⁸⁷Sr/⁸⁶Sr in Etnean lavas. The source of this alkali-enrichment has been hotly debated, with end-member hypotheses involving mantle vs. crustal contributions. To further characterize the evolution of the subvolcanic magma storage and transport system, as well as the timing and source of alkali-enrichment, clinopyroxene from ten samples erupted between 1329 and 2004 was targeted for in situ textural, major element …

Quantifying Weathering Rates On Tropical Volcanic Basse-Terre Island, French Guadeloupe: Insights From U-Series Isotopes In Weathering Rinds, Jacqueline Engel

Open Access Theses & Dissertations

Weathering of volcanic rocks plays many important roles at Earth’s surface such as modifying landscapes, providing nutrients to soil, and regulating atmospheric CO2. U-series isotopes (e.g. 238U-234U-230Th and 232Th) have been established as a chronometer used to constrain the formation rates of weathering rinds in tropical island environments. Here, U-series isotopes and major element concentrations were analyzed in two basaltic-andesite weathering rinds collected from the Deshaies watershed located in the northern, relatively dry (mean annual precipitation (MAP) = 1800 mm) region of tropical Basse-Terre Island, Guadeloupe. The two clasts are referred to as clasts AN-14-7.5 and AN-14-7.6. Elemental mobility trends …

Insights Into The Relationship Between Mixing Duration And Volcanic Explosivity Index (Vei): Pacaya And Fuego Volcanoes, Guatemala, Nicola Mari

Dissertations, Master's Theses and Master's Reports

This study investigates whether the timing of magma mixing phenomena could be related to explosivity and style of volcanic activity. Lava flow and tephra samples, derived from observed, energetically-diverse eruptions, from Pacaya and Fuego volcanoes (Guatemala), were studied, the Volcanic Explosivity Index (VEI) was used as an indicator of eruption intensity. Polarized light microscopy and Scanning Electron Microscopy (SEM) techniques were used for textural and geochemical measurements. Results are interpreted as evolution of mixing through changes in textures of plagioclase and olivine crystals. These suggest that boxy-cellular plagioclase (high frequency in VEI 0 samples) is associated with brief mixing residence …

Mineral And Geochemical Attributes Of The Midcontinent Rift Sequence; An Application For Deep Carbon Dioxide Sequestration, Alsedik Mohamed Ali Abousif

Doctoral Dissertations

"The potential for using the Oronto Group of the Midcontinent Rift (MCR) Sequence for CO₂ sequestration has been disparaged because of low porosity-permeability characteristics, which are largely a result of extensive calcite cementation. This study investigated the potential for using the MCR as a target for CO₂ sequestration by examining reactions involving detrital host-rock minerals at high pressure-temperature conditions that could provide dissolved Ca²⁺, Mg²⁺, and Fe²⁺, and then precipitating these cations as carbonate minerals. The effect of carbonic acid on cement dissolution was also evaluated with respect to enhancing porosity and …

Schreibersite: Synthesis, Characterization And Corrosion And Possible Implications For Origin Of Life, Nikita Latesha La Cruz

USF Tampa Graduate Theses and Dissertations

We present study of the synthesis and reactions of an analog of the meteoritic mineral schreibersite with formula (Fe,Ni)3P, believed to be a prebiotic source of reactive phosphorus that may have prompted the formation of phosphorylated biomolecules near the time of the origin of life (Pasek and Lauretta, 2005). The mineral was synthesized by mixing stoichiometric proportions of elemental iron, nickel and phosphorus and heating in a tube furnace at 820°C for approximately 235 hours under argon or under vacuum, a modification of the method of Skála and Drábek (2002). The mineral was characterized using X-ray diffractometry (XRD), X-ray photoelectron …

Improving Processing By Adaption To Conditional Geostatistical Simulation Of Block Compositions, R. Tolosana-Delgado, Ute A. Mueller, K. G. Van Den Boogaart, C. Ward, J. Gutzmer

Research outputs 2014 to 2021

Exploitation of an ore deposit can be optimized by adapting the beneficiation processes to the properties of individual ore blocks. This can involve switching in and out certain treatment steps, or setting their controlling parameters. Optimizing this set of decisions requires the full conditional distribution of all relevant physical parameters and chemical attributes of the feed, including concentration of value elements and abundance of penalty elements. As a first step towards adaptive processing, the mapping of adaptive decisions is explored based on the composition, in value and penalty elements, of the selective mining units. Conditional distributions at block support are …