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- Manganese oxide (2)
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- Aquatic systems, iron oxide transformation, methane, trace metal speciation, wetland (1)
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- Bronze production, Geochemical analysis, Paleo-environmental pollution, Public health, Shang Dynasty, Yinxu Anyang (1)
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Articles 1 - 19 of 19
Full-Text Articles in Physical Sciences and Mathematics
A Synthesis-Based Approach To The Study Of Fe(Ii) Oxidation In Smectites, Robert Joe Kupper Ii
A Synthesis-Based Approach To The Study Of Fe(Ii) Oxidation In Smectites, Robert Joe Kupper Ii
Arts & Sciences Electronic Theses and Dissertations
Smectite clay minerals are present in diverse environments on Earth as a major product of silicate weathering. Although smectites are compositionally varied, they almost always incorporate iron. Iron-bearing smectites are an important component of the biogeochemical iron cycle, serving as a major iron fraction in many soils and altered rocks as well as participating in redox reactions within the surrounding environment. Iron incorporates into smectites in the ferric [Fe(III)] form at the modern, oxygenated surface of Earth but clays forming in anoxic settings instead incorporate ferrous iron [Fe(II)]. Owing to their ubiquity at the surface of the modern Earth, the …
Fate Of Metals In Presence Of Minerals And Mineral-Organic Assemblages, Neha Sharma
Fate Of Metals In Presence Of Minerals And Mineral-Organic Assemblages, Neha Sharma
McKelvey School of Engineering Theses & Dissertations
Metals can enter aquatic systems from natural and anthropogenic processes associated with weathering, sediment re-suspension, industrial activities, and atmospheric deposition. Metals pose health and environmental risks at high concentrations due to their potential toxicity and bioaccumulation, but many trace metals also serve as essential micronutrients for biogeochemical processes in natural aquatic systems. Biogeochemical processes such as methanogenesis, denitrification, and mercury methylation require transition metals such as nickel (Ni), cobalt (Co), copper (Cu), and molybdenum (Mo) for completion. These biogeochemical processes can be substantial contributors of greenhouse gases, such as methane (CH4) and nitrous oxide (N2O), into the atmosphere. The behavior, …
Nanoscale Interfacial Control Of Ion Behaviors And Caco3 Formation In Environmental Systems, Yaguang Zhu
Nanoscale Interfacial Control Of Ion Behaviors And Caco3 Formation In Environmental Systems, Yaguang Zhu
McKelvey School of Engineering Theses & Dissertations
Interfaces in environmental systems can change the distribution of pollutants and nutrients, determine the fate and transport of nanoparticles, and affect the efficiency of engineering projects. Complex interactions, including electrostatic interactions, Van der Waals interactions, chemical interactions, and ion-surface specific interactions, can all contribute to different ion, ion-pair, and nanoparticle formations near interfaces. Although environmental interfaces play critical roles, only a limited number of studies have considered the nanoscale picture of how they control ions and nanoparticles. Thus, this dissertation addresses three research questions: (1) How does sulfate chemically interact with calcium carbonate (CaCO3) during its heterogeneous formation on quartz …
Trace Metal Speciation And Impacts On Iron Oxide Transformations And Biogeochemical Cycling, Jinshu Yan
Trace Metal Speciation And Impacts On Iron Oxide Transformations And Biogeochemical Cycling, Jinshu Yan
Arts & Sciences Electronic Theses and Dissertations
Trace metals in anoxic aquatic systems are of great importance for iron oxide transformations and biogeochemical cycling. The presence of trace metal can alter iron oxide transformations under anoxic conditions. Trace metals are also essential for microbially-mediated biogeochemical processes occurring in anoxic wetland soils and stream bed sediments, but low availability of these elements may inhibit anaerobic element cycling and transformations. Trace metal speciation is also vital for understanding the environmental control on nutrients and contaminants. Three projects were conducted to explore trace metal speciation and its associated effect on iron oxide transformations and biogeochemical cycling. First, the Fe(II)-promoted conversion …
Paleo-Environmental Pollution Of The Bronze Production During The Shang Period At Anyang, Henan Province, China, Yi-Ling Lin
Paleo-Environmental Pollution Of The Bronze Production During The Shang Period At Anyang, Henan Province, China, Yi-Ling Lin
Arts & Sciences Electronic Theses and Dissertations
Paleo-environmental pollution is invested in both identifying anthropogenic activities and evaluating the environmental condition and its impact on humans to understand human-environment relationships and the human experience of the past. This project first investigates the environmental and health consequences of bronze production during the Shang period at Anyang. As a contribution to the growing scholarship in paleo-environmental and archaeological studies, this dissertation uses Shang bronze production in Anyang as a case study into how paleo- environmental pollution study can inform us about the on environmental and health conditions of lives in the Bronze Age China. Through geochemical analysis (ICP-MS, ICP-OES) …
Petrology, Geochemistry, And Experimental Studies Of Mafic Enclaves And Amphibole At Shiveluch Volcano, Kamchatka, Andrea Elizabeth Goltz
Petrology, Geochemistry, And Experimental Studies Of Mafic Enclaves And Amphibole At Shiveluch Volcano, Kamchatka, Andrea Elizabeth Goltz
Arts & Sciences Electronic Theses and Dissertations
This thesis connects mineralogical, chemical, and physical observables in quenched mafic inclusions from Shiveluch Volcano in Kamchatka and high pressure and temperature experiments to elucidate the water content of primitive magmas at Shiveluch, the timing of magmatic recharge events relative to eruption, and the petrogenetic history of andesites erupted at Shiveluch. Using the petrology of basaltic andesite mafic inclusions erupted from Shiveluch, in Chapter 2, the water content of primitive magmas at Shiveluch is found to be 8-10 wt%, which is two to three times higher than the global average determined by other methods, and the temperature of primitive magmas …
Iron And Manganese Oxidation By Oxyhalogen Species: Implications For Paleoenvironmental Reconstruction On Mars, Kaushik Mitra
Iron And Manganese Oxidation By Oxyhalogen Species: Implications For Paleoenvironmental Reconstruction On Mars, Kaushik Mitra
Arts & Sciences Electronic Theses and Dissertations
As the nearest planetary neighbor with potential earlier habitable conditions, Mars is replete with minerals that hold clues to its past chemistry and evolution of the aqueous systems. Oxidized iron (Fe) and manganese (Mn) minerals on Mars are geochemical markers of such environments in which they formed and record past pH, redox conditions, and intensity of water-rock interaction. Fe and Mn oxides can therefore be used to reconstruct past Martian environmental conditions from settings where aqueous fluids were active. Various processes that form Fe and Mn oxide minerals on Mars have been previously proposed, including chemical oxidation using molecular oxygen …
Potassium Isotope Cosmochemistry, Zhen Tian
Potassium Isotope Cosmochemistry, Zhen Tian
Arts & Sciences Electronic Theses and Dissertations
In Chapter 1, I review the geochemical and cosmochemical properties of potassium (K). Classified as a moderately volatile element, K serves as a robust proxy for understanding the key processes during nebular/planetary evaporation events. I review different mechanisms of volatile depletion among various planetary materials: mass-dependent variations in “nebular” processes; mass-independent variations among different nucleosynthetic sources; or planetary-scale volatile depletion processes. Furthermore, I provide an optimized K purification procedure via ion-exchange chromatography and a high-precision K isotope analysis technique using Neptune plus Multiple Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS) in both “cold plasma” and “dry plasma” methods. I also …
Interaction Of Aqueous U(Vi) With Goethite, Montmorillonite, And Uo2(S), Anshuman Satpathy
Interaction Of Aqueous U(Vi) With Goethite, Montmorillonite, And Uo2(S), Anshuman Satpathy
McKelvey School of Engineering Theses & Dissertations
Uranium contamination in subsurface environments is a matter of great concern throughout the world. Fate and transport of uranium in the subsurface can be controlled by U(VI) adsorption and reduction onto common iron (oxy)hydroxides and clay minerals. Aqueous U(VI) can also exchange uranium atoms with solids comprised of uranium which can potentially lead to changes in the morphology of the uranium-containing solids and affect their stability. First, the performance of multiple surface complexation models (SCMs) on adsorption of U(VI) onto goethite was analyzed for a broad range of input conditions. Individual models could fit the data for which they were …
Experimental Constraints On Igneous Iron Isotopic Fractionation And Diffusion, Kelsey Brianne Prissel
Experimental Constraints On Igneous Iron Isotopic Fractionation And Diffusion, Kelsey Brianne Prissel
Arts & Sciences Electronic Theses and Dissertations
The chapters of this dissertation detail experimental studies that have been conducted in order to determine the diffusivity of iron in the mineral ilmenite (FeTiO3) and the high-temperature behavior of iron isotopes during magma crystallization. The experimental study in Chapter 2 is the first to quantify the rates of cation diffusion in ilmenite. Integrating experimentally determined Fe-Mg and Fe-Mn interdiffusivities with disequilibrium preserved in ilmenite grains from natural volcanic samples, this work has established a new geospeedometry tool with which to estimate the time between magmatic perturbation and eruption on the timescale of hours to months. Chapter 3 investigates the …
Chemistry Of Nanoscale Solids And Organic Matter In Sustainable Water Management Systems, Xuanhao Wu
Chemistry Of Nanoscale Solids And Organic Matter In Sustainable Water Management Systems, Xuanhao Wu
McKelvey School of Engineering Theses & Dissertations
To alleviate global water scarcity and improve public health, engineered water treatment and management systems have been developed for purifying contaminated water and desalinating brackish or ocean water. These engineered systems provide substantial amounts of potable water and lessen environmental concerns about the release of contaminated water. Wastewater treatment plants (WWTPs), water desalination plants (WDPs), and managed aquifer recharge systems (MARs) are three representative sustainable water management (SWM) systems. But the operation of all three poses two fundamental questions: (1) What is the fate of nanoscale solids (e.g., engineered nanomaterials, naturally occurring nanoparticles) in SWM systems and how will their …
Local Environmental Controls On Sulfur Isotope Ratios In Marine Sedimentary Iron Sulfide Minerals, Roger Nicholas Bryant
Local Environmental Controls On Sulfur Isotope Ratios In Marine Sedimentary Iron Sulfide Minerals, Roger Nicholas Bryant
Arts & Sciences Electronic Theses and Dissertations
The controls on the bulk sulfur isotopic composition of marine sedimentary iron sulfides (often referred to simply as pyrite; δ34Spyr) are poorly understood. Nevertheless, many have employed δ34Spyr in efforts to reconstruct the past operation of the biogeochemical sulfur cycle, from the planetary scale down to individual microbial metabolisms. This practice has been thrown into doubt by a growing body of evidence that suggests δ34Spyr is strongly controlled by local environmental conditions. This dissertation describes efforts to determine the mechanisms responsible for the link between local environmental conditions and δ34Spyr. In order to do this, we developed novel laboratory procedures …
Quantifying Lithochemical Diversity Of Martian Materials Using Hierarchical Clustering And A Similarity Index For Classification, Michael Conner Bouchard
Quantifying Lithochemical Diversity Of Martian Materials Using Hierarchical Clustering And A Similarity Index For Classification, Michael Conner Bouchard
Arts & Sciences Electronic Theses and Dissertations
We are currently living in the golden age of robotic exploration of Mars, with a continued robotic presence there since 1997. Next to Earth, Mars is the planet about which we have gathered the most geologic information. Unlike Earth, Mars does not appear to have plate tectonics, and the planet’s primary and secondary crust is dominated by basalts. Understanding the compositional diversity of the materials that make up the martian crust will give us a better insight into the geologic processes that formed the planet and its subsequent evolution. One large and growing source of martian surface compositions is the …
The Effect Of Depositional Environment And Early Marine Diagenesis On Carbonate-Associated Sulfate, Jocelyn Ann Richardson
The Effect Of Depositional Environment And Early Marine Diagenesis On Carbonate-Associated Sulfate, Jocelyn Ann Richardson
Arts & Sciences Electronic Theses and Dissertations
The long-term redox state of Earth’s surface environments is governed by the relative burial proportions of redox-sensitive carbon and sulfur species throughout geologic time. The sulfur isotopic signature of seawater sulfate (δ34SSO4) traces the relative proportions of sulfur buried as sulfide (commonly pyrite) and sulfate (as evaporites, barite or carbonate-associated sulfate) and weathering source to the ocean. Thus, δ34SSO4 is a powerful tool to understand the evolution of redox conditions and the marine biogeochemical sulfur cycle. Due to the spatial and temporal extent of carbonates in the rock record, carbonate-associated sulfate (δ34SCAS) is a common proxy for the isotopic composition …
Seismic Structure Near The Mariana Trench And Deep Earthquake Triggering In The Tonga Flat Slab, Chen Cai
Seismic Structure Near The Mariana Trench And Deep Earthquake Triggering In The Tonga Flat Slab, Chen Cai
Arts & Sciences Electronic Theses and Dissertations
This dissertation utilizes multiple techniques of earthquake location and seismic tomography to investigate deep seismicity in the Tonga flat slab region and the upper mantle structure of the Mariana subduction zone. I study the rupture property and aftershock distributions of the largest earthquake ever recorded in the Tonga flat slab region, defined by scattered seismicity and velocity anomalies. These, along with background seismicity, regional 3-D seismic velocity model and tectonic reconstructions of relict Vitiaz subduction zone, suggest the earthquakes are occurring in the final portion of the slab subducted at the now inactive Vitiaz trench. The associated Coulomb stress change …
The Impact Of Small Organic Acids On Iron And Manganese Mineral Transformations And The Fate Of Trace Metals, Elaine Denise Flynn
The Impact Of Small Organic Acids On Iron And Manganese Mineral Transformations And The Fate Of Trace Metals, Elaine Denise Flynn
Arts & Sciences Electronic Theses and Dissertations
Iron and manganese oxides are ubiquitous in soils and sediments and play a critical role in the geochemical distribution of trace elements and heavy metals through adsorption and coprecipitation. At redox interfaces, biogeochemical processes generate conditions with coexisting dissolved Fe(II) and solid-phase Fe(III). In such systems, Fe(II) induces the recrystallization of iron oxides through coupled mineral growth and dissolution due to electron transfer as oxidative adsorption of Fe(II) and reductive dissolution of Fe(III) occur. Aqueous Mn(II) adsorption onto Mn(III/IV) oxides also likely involves oxidation although likely through different mechanisms than that of the Fe system because of the potential for …
Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung
Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung
McKelvey School of Engineering Theses & Dissertations
Manganese (hydr)oxide (Mn (hydr)oxide) minerals are ubiquitous in aquatic and terrestrial environments. These minerals have high surface areas and are highly sorptive and redox active. From decades of accumulated knowledge about natural redox cycling, we have found that Mn (hydr)oxides play critical roles as electron donors and acceptors in elemental geochemical cycling and biological metabolisms in nature. Thus, Mn (hydr)oxides have garnered increasing interest to understand natural systems. Considering the variety of redox reactions with Mn (hydr)oxides in nature, it is also expected that there should be diverse pathways to form Mn (hydr)oxides through abiotic and biotic processes. Previous studies …
Aluminosilicate Dissolution And Silicate Carbonation During Geologic Co2 Sequestration, Yujia Min
Aluminosilicate Dissolution And Silicate Carbonation During Geologic Co2 Sequestration, Yujia Min
McKelvey School of Engineering Theses & Dissertations
Geologic CO2 sequestration (GCS) is considered a promising method to reduce anthropogenic CO2 emission. Assessing the supercritical CO2 (scCO2)¬–gas or liquid phase water (g, l)–mineral interactions is critical to evaluating the viability of GCS processes. This work contributes to our understanding of geochemical reactions at CO2¬–water (g, l)–mineral interfaces, by investigating the dissolution of aluminosilicates in CO2-acidified water (l). Plagioclase and biotite were chosen as model minerals in reservoir rock and caprock, respectively. To elucidate the effects of brine chemistry, first, the influences of cations in brine including Na, Ca, and K, have been investigated. In addition to the cations, …
The Effect Of Diffusive Transport On Mineral Carbonation In Geologic Carbon Sequestration, Wei Xiong
The Effect Of Diffusive Transport On Mineral Carbonation In Geologic Carbon Sequestration, Wei Xiong
McKelvey School of Engineering 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 …