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1
McAlister, John J. "Characterisation of basaltic weathering products by modern analytical techniques." Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329424.
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Majumder, Santanu. "Pollution assessment of arsenic in groundwater: geochemistry and analytical aspects." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/125308.
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Apart from the geological controls that can cause As mobilization in groundwater in the Bengal Delta Plain, local anthropogenic factors may also contribute to some extent. Investigations showed that As(III) get enriched in the groundwater after the monsoonal season. This could be due to the enhanced reducing conditions in the aquifer post-monsoonal recharge. The larger inorganic colloids were responsible to scavenge As(III) and the smaller organic/organo-metallic colloids were found to scavenge As(V). A study was carried out to improve the Solar Oxidation and Removal of Arsenic (SORAS) for rural population, using tomatoes instead of lemons, showing that tomato was more efficient and cost-effective than lemon or lime. A novel technique combining hollow fiber liquid phase microextraction (HF-LPME) with Total Reflection X-Ray Fluorescence (TXRF) for the determination and speciation of As in groundwater was developed. The results in the laboratory samples were found encouraging and applied to natural samples successfullyAdemás de los controles geológicos, los factores antropogénicos contribuyen también a la movilización de arsénico en el agua subterránea del Bengal Delta Plain. La concentración de As(III) aumenta después de la temporada del monzón, debido a las condiciones más reductoras en el acuífero. El As(III) se encuentra asociado a coloides inorgánicos de mayor tamaño mientras que los coloides orgánicos/organometálicos más pequeños contienen As(V). Se llevó a cabo un estudio para mejorar el proceso SORAS (Solar Oxidation and Removal of Arsenic) comparando diferentes fuentes de citrato, y demostrando que el tomate es más eficiente y económico que el limón o la lima. Se ha desarrollado un método novedoso para la determinación y especiación de As basado en microextracción en fase líquida en fibra hueca (HF-LPME) combinados con fluorescencia de rayos X con reflexión total (TXRF), y que ha sido aplicado con éxito en diferentes muestras de aguas naturales
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Marr, Robert A. (Robert Allen) 1965. "An investigation of Zr and Ti-bearing alkali aluminosilicate glasses : solubility experiments, Raman spectroscopy and 23Na NMR analyses." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35011.
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The solubility of Zr-bearing minerals in peralkaline, H2O-saturated alkali aluminosilicate melts with or without added F reaches a maximum of about 4 and 3.5 wt.% ZrO2 respectively at approximately 57 wt.% SiO2. The saturating phase for melts with SiO2 content above this threshold is zircon. In the halogen-free experiments, the saturating phase for melts with lower silica content is wadeite (K2ZrSi 3O9), while ZrO2 crystallizes from melts with 1 wt.% added F. Experiments with Cl-bearing melts indicate no maximum solubility of Zr minerals; the solubility remains at 2 to 2.2 wt.% ZrO2 across a wide compositional range. The saturating phases in the Cl-bearing melts are the same as those of the F-bearing melts and the transition from ZrO 2 to zircon occurs at the same composition. The positive slope of the wadeite saturation curve on XZrO2-XSiO2 plots for the halogen-free melts suggests that increasing SiO2 activity increases the solubility of wadeite.Peralkaline Ti,Zr-bearing sodium aluminosilicate glasses have been analyzed by Raman spectroscopy to determine the effect of Cl on glass structure. The spectra of the Ti-bearing glasses show a significant difference between the Cl-free and the Cl-bearing composition. The Cl-free glass spectrum contains a strong, asymmetric peak at 900 cm--1 which is associated with Ti in five-fold coordination. This peak is shifted to higher frequency and becomes more symmetric with the addition of 0.3 wt.% Cl. Deconvolution of the high-frequency waveband suggests that differences between spectra result from the contribution of a peak at 945 cm--1. This peak is believed to be the result of Ti-O vibrations in fully-polymerized titanate tetrahedra. It is proposed that the addition of Cl destabilizes [5] Ti in favour of tetrahedral coordination as a result of competition between Cl and titanate groups for alkalis.
23Na NMR MAS analyses of a suite of Na-aluminosilicate glasses with Na/Al = 2 and varying SiO2 content has revealed a trend toward more negative chemical shift (greater shielding of the nucleus) as the glass structure becomes more polymerized, i.e. the average number of non-bridging oxygen atoms per tetrahedron (NBO/T) decreases. This trend is observed only for glasses with NBO/T ≤ 0.3. For more polymerized glasses no change in chemical shift is measured. (Abstract shortened by UMI.)
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Lewin, Kathryn. "I.C.P analytical techniques applied to the hydrogeochemistry of the southern Lincolnshire Limestone aquifer." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/67aecf23-a0ad-4e4e-88f9-f5545b85a700/1/.
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The hydrogeochemistry of the southern Lincolnshire Limestone is investigated employing inductively coupled plasma-optical emission spectrometry (ICP-OES) as the primary analytical technique. Two simultaneous, multi-element instruments were used. The principles of the technique and comparisons of the hardware, operating conditions and routine sample preparation methods are outlined and realistic levels of precision and detection limits evaluated. The range of determinations in the groundwaters was extended by the development of novel sample treatment techniques including the determination of dissolved sulphide down to the 1 level using a gas-liquid separator, and the determination of rare earth elements in groundwater evaporation residues. The methods were applied to the analysis of groundwaters and rocks of the Lincolnshire Limestone in southern Lincolnshire. The geology, hydrogeology and hydrochemistry of the aquifer are reviewed and the sample collection methods described, stressing the precautions taken to avoid contamination. The Lincolnshire Limestone is an aquifer of considerable heterogeneity, argillaceous limestones are intercalated with pure oolites and it is confined by predominantly clastic formations. The major element chemistry of the groundwaters follow a down-dip trend between calcium-bicarbonate-sulphate waters near outcrop and saline, non-potable waters in the east. The groundwaters are sub-divided into zones based on the processes of calcite dissolution, ion exchange and the mixing of recharge and saline interstitial waters. Minor and trace element behaviour is controlled by a combination of oxidation-reduction reactions, adsorption on clay minerals and organic matter, mineral solubilities, complex formation andgroundwater pH. Ultimately the low levels of most trace metals are limited by their low abundance in the limestone. Temporal hydrochemical trends are identified, and the influence of man, with reference to the down-gradient migration of agrichemical pollutants (e.g. nitrates) is assessed. Fluctuations in the movement of the potable/saline water interface are noted and theories on the origin of the saline waters reviewed.
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Engström, Emma. "Fractionation of the stable silicon isotopes : analytical method developments and selected applications in geochemistry." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18719.
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During the last few decades, variations in the 'natural' isotopic abundances of stable elements (termed 'fractionation') have received considerable interest from the scientific community. Though analytical methods and techniques for the measurement of isotopic abundances with adequate figures of merit have been available for light elements (e.g. B, C, N and O) for some time, and the wealth of data produced has secured maturity status for such applications, relatively modest progress in fractionation studies devoted to high-mass elements has been made until recently, mainly because of constraints of the available analytical techniques. The situation has changed drastically with the advent of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), with the number of reports about natural fractionation of Fe, Cu, Zn, Mo, Cd, Sn increasing exponentially during the recent years. In spite of the high Si abundance in nature and the importance of the element in many areas of the Earth sciences (focusing on e.g. weathering, the global Si cycle, paleoclimate studies, paleoceanography, and biological uptake), the available information on Si isotope fractionation remains rather limited due to the laborious and hazardous chemical purification procedures associated with the analyses. The focus of this thesis was the development of analytical methods for the precise and accurate measurements of Si isotope ratios, which is an absolute requirement for meaningful fractionation studies, in various matrices. This work involved detailed studies on sample preparation (including matrix separation) and refining the measurement protocol by using high resolution MC-ICP-MS. In the former stages, quantitative analyte recovery, thorough control of contamination levels and purification efficiency were the major targets, while severe spectral interferences and the need for adequate instrumental mass bias corrections challenged the latter. The performance of the method was tested in the first inter- laboratory performance assessment study of its kind with good results. As limited examples of applications, studies on Si isotope fractionation in aqueous, plant and humus samples were performed utilizing methods developed. The efficient analyte separation, high-resolution capability of the instrument, quantitative Si recovery and accurate mass bias correction using Mg as internal standard, allowed the determination of the Si isotopic composition of natural waters and biological samples with long-term reproducibility, expressed as twice the standard deviation (2σ), equal to or less than 0.10‰ for δ29Si and 0.25‰ for δ30Si. Furthermore, the presence of a challenging spectral interference on 29Si originating from 28SiH+ was revealed during this study, indicating that instrumental resolution in excess of 3500 is required for interference-free Si isotopic analyses. However, despite complete removal of N-, O-, and C-containing interferences appearing on the high-mass side of the Si isotopes, it was found that exact matching of both the acid matrix and the Si concentration are mandatory due to tailing from the abundant 14N16O+ interference on 30Si. This thesis also includes results from the first study of the Si isotopic homogeneity of major biomass components from a defined area in Northern Sweden covered by boreal forest. Since the potential impact of vegetation on the terrestrial biogeochemical cycle has attracted considerable interest, thorough characterization of the Si isotopic composition of the biomass potentially allows the utilization of this isotope system in the assessment of the relative contributions of biogenic and mineral silica in plants, soil solutions and natural waters (including fresh-, brackish- and marine waters). Isotopic analyses of the biological materials yielded a surprisingly homogenous silicon isotopic composition (relative to the NBS28 Si reference material), expressed as δ29Si (2σ), ranging from (- 0.14 ± 0.05)‰ to (0.13 ± 0.04)‰ Furthermore, elemental and isotopic analysis of local airborne particulate matter suggests that vegetation also accumulates silica via incorporation of exogenous Si containing primary and secondary minerals (in addition to root uptake of non-ionic silicic acid), a fact that has been neglected in previously published studies. This strongly indicates that the presence of potential surface contributions must be considered during in situ silicon uptake studiesGodkänd; 2007; 20071011 (ysko)
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Robson, William. "The separation of the polar constituents of petroleum." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/12226.
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Identification of the heteroatom (nitrogen, sulphur, and oxygen; NSO)-containing compounds of petroleum is of key importance when considering industrial and environmental issues associated with crude oil production. The inherent molecular complexity of petroleum is such that detailed compositional investigations must ideally be preceded by some form of pre-fractionation. However, the more commonly performed methods of crude oil fractionation are often insufficient in the extent to which they separate oils, not allowing defined “molecular” fractions to be obtained and thus hindering more detailed investigations. The following work therefore focused on the development of chromatographic methods to aid in the characterisation of NSO compounds present within crude oils. A novel solid phase extraction (SPE) procedure was developed utilising both ion exchange and adsorption chromatography. The method enabled fractions broadly defined as ‘saturated’ hydrocarbons; ‘aromatic’ hydrocarbons; basic nitrogen compounds; naphthenic acids; phenols and other oxygen-containing species; carbazoles; sulfoxides; and thiophenes, to be isolated reproducibly and quantitatively from relatively small crude oil samples (~ 0.5 g). Assessment of method selectivity with a suite of ‘model’ compounds showed that the resulting fractions were quite well defined, with classes of ‘model’ compounds being isolated within discrete fractions. Application to five crude oils of widely varying properties and origins, such as API gravity (12.1−38.3°), demonstrated the potential for the wide-ranging use of the method. Sample recoveries were high (77−98%) with simple evaporative losses accounting for the majority of sample loss. Repeatability was also high, demonstrated by triplicate analyses of ‘model’ compound mixtures, oils spiked with ‘model’ compounds and oils alone. Subsequent, more detailed, analysis of the fractions using multidimensional gas chromatography-mass spectrometry (GC×GC-MS) and liquid chromatography-highresolution accurate mass-mass spectrometry (LC-HRAM-MS) showed the advantages of the new isolation method. For example, alkylated series (C1-5) of quinolines, carbazoles, fluorenones, dibenzothiophenes and xanthones were identified within their predicted fractions. Furthermore, comparison of mass spectra obtained from GC×GC-MS analyses with reference spectra resulted in the tentative identification of compounds hitherto not previously reported in crude oils, again illustrating the advantage of the isolation method. Novel series of thioxanthones, tocopherols (E vitamins) and terpenoidal sulfoxides and ketones were assigned within the isolated fractions. Following the successful evaluation of the method, the scheme was subsequently employed to investigate the effects of changing geochemical parameters on the composition of isolated NSO-containing compounds. For example, studies of NSO fractions from series of crude oils at different stages of thermal maturity or of biodegradation, led to the identification of a number of potential new molecular markers within the basic-nitrogen and ketone fractions. This work shows clear potential for the developed NSO isolation method to be used in further compositional studies as a tool to aid in geochemical investigations.
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Sulley, Addo Tahiru. "EFFECT OF SAMPLE MISCUT ON DISSOLUTION KINETICS OF CALCITE (104) CLEAVAGE SURFACES." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1385390795.
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Saad, Emily M. "Elemental, isotopic, and particle fingerprinting of dust sources in the San Francisco Peaks, Arizona." Thesis, Northern Arizona University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1537808.
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This study examines dust in the San Francisco Peaks located on the Colorado Plateau of northern Arizona, USA. Sample dusts were collected from potholes on Humphreys Peak (35o20'22"N, 111o41'42"W) in order to detect exogenous material and constrain dust sources. Bulk dust and local rock were characterized by Sr and Nd isotope fingerprints as well as elemental composition. Sr and Nd isotope ratios were analyzed by MC-ICP-MS; trace element concentrations were analyzed by Q-ICP-MS. Mineralogical analyses were also performed in an effort to characterize individual particles. Mineral grains were separated from bulk samples by conventional heavy mineral separations. The heavy fraction was imaged and characterized by SEM/EDX.
Both the isotopic and elemental bulk analyses indicated that the dust composition reflected not only a weathered local rock material but also exogenous material of continental crust origin. The dust was characterized by an average 87Sr/86Sr ratio of 0.7095 ± 0.0010 and an average ε Nd of -7.13 ± 0.97. These signatures systematically and significantly deviate from the isotope fingerprints of the local rock, which exhibited an average 87Sr/86Sr ratio of 0.7037 ± 0.0002 and an average εNd of -2.43 ± 0.43. The negative correlation between εNd and 87Sr/86Sr is consistent with two component mixing of rock evolved from a mantle source and continental crust derived material.
Several geologically relevant trace elements were found to have significantly different average concentrations in the dust than in the local rock samples. Furthermore, the elemental abundances of most elements in the dust samples suggested a mixture of local rock and continental crust end members with the exception of Pb, which indicated an anthropogenic influence exhibiting enrichment factors between 1.65 and 7.44.
The mineral analysis provided further evidence of exogenous material and offered the opportunity for further constraint of the sources. Zircons were identified only in the dust and will be analyzed for U-Pb signatures in order to characterize the isotopic fingerprint of individual mineral grains, which will better distinguish external sources. Diatom skeletons were also found exclusively in the dust samples and offer a unique opportunity to more specifically implicate sources through a diatom assemblage.
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Mojzsis, Stephen J. "Ancient sediments of Earth and Mars /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9823711.
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Van, Achterbergh Esmé. "The development of the national accelerator centre proton microprobe as an analytical tool in geochemistry." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/22046.
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Bibliography: pages 94-99.This thesis describes work performed to establish and demonstrate a quantitative trace element microanalysis technique for geological material using protons accelerated by the Van de Graaff Accelerator at the National Accelerator Centre (NAC) in Faure near Cape Town. The method relies on the analysis of Proton Induced X-ray Emission (PIXE) spectra, interpreted with the help of the GeoPIXE software package. The use of the Si(Li) energy dispersive detector provides simultaneous multi-element detection at the parts-per-million (ppm) level, and a scanning beam facility permits trace element distributions to be studied at these levels. The calibration of the detector efficiency and the thicknesses of selectable X-ray attenuating filters was performed using pure elemental samples. This involved the accurate determination of the target to detector distance, the thickness of the active volume of the Si(Li) detector crystal, the thicknesses of all the absorbing layers between the sample and the detector crystal, and the assessment of the effects of incomplete charge collection in the detector.
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Popelka-Filcoff, Rachel S. "Applications of elemental analysis for archaeometric studies analytical and statistical methods for understanding geochemical trends in ceramics, ochre and obsidian /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4495.
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Thesis (Ph. D.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 7, 2007) Includes bibliographical references.
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Engström, Emma. "Fractionation of the stable silicon isotopes studied using MC-ICP-MS : analytical method developments and applications in geochemistry /." Luleå : Department of Chemical Engineering and Geosciences, Division of Geosciences, Luleå University of Technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3522867.
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Sannigrahi, Poulomi. "Composition and cycling of natural organic matter: Insights from NMR spectroscopy." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11272005-094111/.
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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2006.Taillefert, Martial, Committee Member ; Weber, Rodney, Committee Member ; Stack, Andrew, Committee Member ; Benner, Ronald, Committee Member ; Ingall, Ellery, Committee Chair. Includes bibliographical references.
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Paul, Bence Timothy. "A new perspective on melt inclusions : development of novel in-situ analytical protocols /." Connect to thesis, 2006. http://eprints.unimelb.edu.au/archive/00002977.
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Johnson, Aaron W. "Regional-scale geochemical analysis of carbonate cements : reconstructing multiple fluid interactions related to dolomitization and mineralization in lower carboniferous rocks of the Irish Midlands /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3101027.
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O'Driscoll, Cynthia Marie. "The application of trace element geochemistry to determine the provenance of soapstone vessels from Dorset Palaeoeskimo sites in western Newfoundland /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,164162.
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Lammers, Kristin D. "Carbon dioxide sequestration by mineral carbonation of iron-bearing minerals." Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/339925.
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ChemistryPh.D.
Carbon dioxide (CO2) is formed when fossil fuels such as oil, gas and coal are burned in power producing plants. CO2 is naturally found in the atmosphere as part of the carbon cycle, however it becomes a primary greenhouse gas when human activities disturb this natural balanced cycle by increasing levels in the atmosphere. In light of this fact, greenhouse gas mitigation strategies have garnered a lot of attention. Carbon capture, utilization and sequestration (CCUS) has emerged as a possible strategy to limit CO2 emissions into the atmosphere. The technology involves capturing CO2 at the point sources, using it for other markets or transporting to geological formations for safe storage. This thesis aims to understand and probe the chemistry of the reactions between CO2 and iron-bearing sediments to ensure secure storage for millennia. The dissertation work presented here focused on trapping CO2 as a carbonate mineral as a permanent and secure method of CO2 storage. The research also explored the use of iron-bearing minerals found in the geological subsurface as candidates for trapping CO2 and sulfide gas mixtures as siderite (FeCO3) and iron sulfides. Carbon dioxide sequestration via the use of sulfide reductants of the iron oxyhydroxide polymorphs lepidocrocite, goethite and akaganeite with supercritical CO2 (scCO2) was investigated using in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The exposure of the different iron oxyhydroxides to aqueous sulfide in contact with scCO2 at ~70-100 ˚C resulted in the partial transformation of the minerals to siderite (FeCO3). The order of mineral reactivity with regard to siderite formation in the scCO2/sulfide environment was goethite < lepidocrocite ≤ akaganéite. Overall, the results suggested that the carbonation of lepidocrocite and akaganéite with a CO2 waste stream containing ~1-5% H2S would sequester both the carbon and sulfide efficiently. Hence, it might be possible to develop a process that could be associated with large CO2 point sources in locations without suitable sedimentary strata for subsurface sequestration. This thesis also investigates the effect of salinity on the reactions between a ferric-bearing oxide phase, aqueous sulfide, and scCO2. ATR-FTIR was again used as an in situ probe to follow product formation in the reaction environment. X-ray diffraction along with Rietveld refinement was used to determine the relative proportion of solid product phases. ATR-FTIR results showed the evolution of siderite (FeCO3) in solutions containing NaCl(aq) concentrations that varied from 0.10 to 4.0 M. The yield of siderite was greatest under solution ionic strength conditions associated with NaCl(aq) concentrations of 0.1-1 M (siderite yield 40% of solid product) and lowest at the highest ionic strength achieved with 4 M NaCl(aq) (20% of solid product). Based partly on thermochemical calculations, it is suggested that a decrease in the concentration of aqueous HCO3- and a corresponding increase in co-ion formation, (i.e., NaHCO3) with increasing NaCl(aq) concentration resulted in the decreasing yield of siderite product. At all the ionic strength conditions used in this study, the most abundant solid phase product present after reaction was hematite (Fe2O3) and pyrite (FeS2). The former product likely formed via dissolution/reprecipitation reactions, whereas the reductive dissolution of ferric iron by the aqueous sulfide likely preceded the formation of pyrite. These in situ experiments allowed the ability to follow the reaction chemistry between the iron oxyhr(oxide), aqueous sulfide and CO2 under conditions relevant to subsurface conditions. Furthermore, very important results from these small-scale experiments show this process can be a potentially superior and operable method for mitigating CO2 emissions.
Temple University--Theses
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Saunders, Katharine Emma. "Micro-analytical studies of the petrogenesis of silicic arc magmas in the Taupo Volcanic Zone and southern Kermadec Arc, New Zealand : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy in Geology /." ResearchArchive@Victoria e-Thesis, 2009. http://hdl.handle.net/10063/943.
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Lundberg, Paula. "Geochemical processes in mine waste subjected to a changing chemical environment: Fe speciation in leachate water from column experiments." Thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65380.
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Oxidation of sulfidic mine waste is of significant environmental concern due to the consequent formation of acid rock drainage (ARD), deteriorating the water quality of natural water systems. Iron (Fe) and sulfur (S) are two major redox elements involved in these reactions and typically the major redox-sensitive elements (whose solubility, speciation, and mobility are affected by pH and Eh) in water affected by ARD. Measurements of Fe and S species concentrations may reveal valuable information about geochemical processes in mine waste but are typically included when analyzing the chemical composition of ARD. In this study, robust and portable methods for the determination of Fe and S species concentrations in leachate water affected by sulfidic mine waste were tested and evaluated. The leachate water resulting from interaction with high- and low-sulfide waste rock was collected from three leaching columns, each reflecting different geochemical environments that could occur during mine waste management: (1) fully oxidized conditions (reference column), (2) gradual oxygen depletion from atmospheric level to <1% (anoxic column), (3) treatment with alkaline industrial residual material (alkaline column). The leachate water was analyzed for its pH, Eh, electric conductivity (EC), and major and trace elements. UV-Vis spectrophotometric ferrozine method was tested and applied for Fe speciation and concentration analysis, allowing determination of Fe(II) and Fetot and further calculation of Fe(III) as a difference. The method was found to achieve accurate and reliable results. Turbidimetry was tested and evaluated for dissolved sulfate analysis, and even though the analytical precision was poorer, ca. ±20%, the method provides useful semi-quantitative estimations of dissolved sulfate concentrations. Both spectrophotometry and turbidimetry are easy to perform and utilizes robust, cheap and portable instrumentation. Leachate water from the high and low sulfide experiments had pH and Eh in the range of pH 2.6 – 12 and Eh 200 – 720 mV and pH 3.5 – 4 and Eh 550 – 700 mV, respectively. Measurements of iron species and sulfate concentrations revealed that sulfate was the dominating S species and during the background leachate Fe(II) was the predominant Fe oxidation state. Upon decreasing oxygen saturation and pH in the anoxic column, Fe speciation in the reference and anoxic column differed, with the relative importance of Fe(III) increasing in the anoxic column. Total Fe, pH and Eh potential measured in the leachate water did not respond to decreasing oxygen saturation, but changes in the Fe redox speciation coincided with this decrease. Under alkaline conditions, total Fe and sulfate concentrations decreased in the alkaline environment, indicating their immobilization in the solid phase. Geochemical calculations were carried out to gain further understanding of the dominant reactions in the columns. Theoretical values of Fe(II) and Fe(III) concentrations were calculated from the measured redox potential, and these were found to deviate from the measured concentrations. Therefore, estimation of Fe species distribution from redox measurements using a Pt-electrode is not considered sufficient in these systems. Mineral saturation indices of common secondary minerals associated with ARD indicated dissolution of ferrihydrite, jarosite and schwertmannite in the leachate water from the anoxic column. This suggests that these minerals are the probable source of the Fe and sulfate, as well as As and Cu released to the leachate water.
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Coish, Diane Wanda. "Applicability of laser ablation and partial dissolution ICP-MS techniques on Mn-Fe-oxide coatings of stream pebbles to mineral exploration and environmental monitoring." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0033/MQ62378.pdf.
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Elvy, Shane Brett. "Geochemical studies of base and noble metal compounds /." View thesis, 1998. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030821.172648/index.html.
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Thesis (Ph.D.) -- University of Western Sydney, Nepean, 1998.CD-ROM (appendix) contains complete lists of the species distribution for each water sample; the constant correction spreadsheet; and, the possible stability constants for aqueous ionic species as well as the data ranges for both the Girilambone study and the North Mungana study. A thesis presented in accordance with the regulations governing the award of the degree of Doctor of Philosophy in the University of Western Sydney, Nepean, School of Science. Includes bibliographical references at end of each chapter.
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Muterspaw, Taylor M. "The Formation of Prenucleation Clusters for Calcium Fluoride." Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1630356298649522.
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Bell, Benjamin. "Advancing the application of analytical techniques in the biological chemistry of sporopollenin : towards novel plant physiological tracers in Quaternary palynology." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/advancing-the-application-of-analytical-techniques-in-the-biological-chemistry-of-sporopollenin-towards-novel-plant-physiological-tracers-in-quaternary-palynology(59605f2b-642a-4ea9-8921-4c926217e6f2).html.
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Palynology, the study of organic microfossils, is an important tool for improving our understanding of past environments and landscapes. Palynology provides a wealth of information from which climatic and environmental conditions can be inferred. However, inferred climatic and environmental conditions are often open to interpretation. Assumptions made about past climate conditions from pollen assemblages often rely on qualitative understanding of modern-day vegetation distributions, rather than empirical relationships. Historic anthropogenic impact on the environment must also be inferred, and assessments made as to whether vegetation changes are a result of climate change or human impact. This study seeks to address some of the questions that arise through the interpretation of pollen assemblages, by establishing empirical relationships between the geochemistry of modern pollen and climate or environmental controls. It focuses on the pollen of the climatically sensitive montane conifer Cedrus atlantica, which is distributed across the mountains of Morocco and Algeria. The study investigates aspects of modern pollen geochemistry and morphology and finds a strong relationship between the stable carbon isotope composition of modern pollen and mean annual precipitation (r2 = 0.54, p <0.001) and summer precipitation (r2 = 0.63, p <0.0001). Furthermore, a stronger relationship exists with aridity measured using the self-calibrating Palmer Drought Severity Index (r2 = 0.86, p <0.0001), suggesting that the stable carbon isotope composition of Cedrus atlantica pollen is influenced by environmental moisture availability. The study also finds there is an increased abundance of ultraviolet absorbing compounds (UACs) in modern Cedrus atlantica pollen with increasing summer UV-B flux. This relationship was evident with samples growing in their native range (r2 = 0.84, p <0.0001), but not with samples from outside this range (r2 = 0.00, p = 0.99), suggesting a possible genetic influence. Lastly, the study finds that grain size of Cedrus atlantica pollen is highly variable within and between samples, and we rule out climatic control on pollen grain size. These results suggest that quantitative relationships can be established between the geochemistry of Cedrus atlantica pollen and environmental and climatic influences. Stable carbon isotope analysis of fossil pollen could be used as a proxy for reconstruction of summer moisture availability, while analysis of UACs in fossil pollen could be used as a proxy for the reconstruction of summer UV-B flux. These proxies will enhance our understanding of climatic and environmental change in Northwest Africa and will complement existing palynological techniques for environmental and climate reconstruction. Palynology, the study of organic microfossils, is an important tool for improving our understanding of past environments and landscapes. Palynology provides a wealth of information from which climatic and environmental conditions can be inferred. However, inferred climatic and environmental conditions are often open to interpretation. Assumptions made about past climate conditions from pollen assemblages often rely on qualitative understanding of modern-day vegetation distributions, rather than empirical relationships. Historic anthropogenic impact on the environment must also be inferred, and assessments made as to whether vegetation changes are a result of climate change or human impact. This study seeks to address some of the questions that arise through the interpretation of pollen assemblages, by establishing empirical relationships between the geochemistry of modern pollen and climate or environmental controls. It focuses on the pollen of the climatically sensitive montane conifer Cedrus atlantica, which is distributed across the mountains of Morocco and Algeria. The study investigates aspects of modern pollen geochemistry and morphology and finds a strong relationship between the stable carbon isotope composition of modern pollen and mean annual precipitation (r2 = 0.54, p <0.001) and summer precipitation (r2 = 0.63, p <0.0001). Furthermore, a stronger relationship exists with aridity measured using the self-calibrating Palmer Drought Severity Index (r2 = 0.86, p <0.0001), suggesting that the stable carbon isotope composition of Cedrus atlantica pollen is influenced by environmental moisture availability. The study also finds there is an increased abundance of ultraviolet absorbing compounds (UACs) in modern Cedrus atlantica pollen with increasing summer UV-B flux. This relationship was evident with samples growing in their native range (r2 = 0.84, p <0.0001), but not with samples from outside this range (r2 = 0.00, p = 0.99), suggesting a possible genetic influence. Lastly, the study finds that grain size of Cedrus atlantica pollen is highly variable within and between samples, and we rule out climatic control on pollen grain size. These results suggest that quantitative relationships can be established between the geochemistry of Cedrus atlantica pollen and environmental and climatic influences. Stable carbon isotope analysis of fossil pollen could be used as a proxy for reconstruction of summer moisture availability, while analysis of UACs in fossil pollen could be used as a proxy for the reconstruction of summer UV-B flux. These proxies will enhance our understanding of climatic and environmental change in Northwest Africa and will complement existing palynological techniques for environmental and climate reconstruction.
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Ruhl, Isaiah Daniel. "High Resolution Magic Angle Spinning NMR Studies of Botryococcus Braunii." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1244008200.
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Calero, Adolfo Eberhard. "An Investigation of Fertilizer-Derived Uranium in Ohio Agricultural Soils." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587651244115868.
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Moreau, Pauline. "Etude des interactions entre Eu(III) et des particules d'alumine en présence d'acides phénoliques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00789479.
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Dans le cadre de la compréhension des mécanismes de pollution environnementale par les éléments radioactifs, ce travail de thèse s'est intéressé aux interactions existant dans des systèmes comprenant les trois entités europium(III) (pris comme analogue des actinides Am(III) et Cm(III)), acides phénoliques (produits de dégradation de la lignine et antifongiques présents naturellement dans les sols) et l'alumine (représentatif des sites de surface présents dans l'environnement). Différents niveaux d'analyse ont été employés pour cette étude ; l'échelle macroscopique - par la quantification de l'adsorption de Eu(III) et/ou des acides phénoliques sur la surface - et l'échelle microscopique - par l'étude de l'environnement chimique de Eu(III) par spectroluminescence laser à résolution temporelle (SLRT). Au préalable, les systèmes binaires, c'est à dire des systèmes contenant deux des trois entités citées précédemment, ont été étudiés. Ainsi, les constantes de complexation de Eu(III) par trois acides phénoliques (acides 4-hydroxybenzoïque, 3,4-dihydroxybenzoïque et 3,4,5 trihydroxybenzoïque) ont été déterminées par SLRT et une étude en modélisation moléculaire (DFT) a été réalisée sur des systèmes analogues La(III)-acides. La sorption des trois acides sur les sites aluminol a été modélisée à l'aide de modèles de complexation de surface. Les analyses menées sur deux systèmes ternaires (acides 4-hydroxybenzoïque, 3,4-dihydroxybenzoïque) ont mis en évidence une synergie pour la sorption de Eu(III) par ces acides sur Al2O3. Une empreinte spectrale d'un complexe ternaire a été isolée dans le cas du système Eu(III)/acide 4-hydroxybenzoïque/Al2O3.
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McGuire, Sara Anne. "Noxious Smoke and Silent Killers: Identity, Inequality, Health, and Pollutant Exposure During England’s Industrial Revolution." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1594403381913239.
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Jantzi, Sarah C. "Elemental Analysis and Forensic Comparison of Soils by Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/967.
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The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS.
Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets.
An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes.
Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets.
Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.
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Losno, Rémi. "Chimie d'éléments minéraux en traces dans les pluies méditerranéennes." Phd thesis, Université Paris-Diderot - Paris VII, 1989. http://tel.archives-ouvertes.fr/tel-00814327.
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L'objet de ce travail est de déterminer les causes de la partition de certains éléments-trace entre les phases aqueuse et insoluble . Ces éléments ont été choisis, d'une part pour leur importance dans les cycles biogéochimiques de la terre, et d'autre part pour leur intérêt dans la compréhension de la chimie de la pluie. Il s'agit des éléments Na, Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, Cu, Zn et Pb. Pour mener à bien ces recherches, nous avons mis au point des méthodes de travail dans des conditions ultra propres, en insistant particulièrement sur le protocole de lavage du matériel utilisé. Nous décrivons ensuite les méthodes de prélèvement des pluies, de séparation des phases aqueuse et insoluble , et d'analyse des éléments étudiés. Ce développement a été rendu nécessaire pour pouvoir obtenir des données fiables sur les métaux traces. Afin de pouvoir exploiter au mieux les résultats obtenus, nous essayons de déterminer les mécanismes par lesquels la matière s'incorpore dans une goutte de pluie. Puis, en liaison avec les études conjointes sur l'aérosol, nous discutons de l'origine de cette matière et nous en concluons à la prédominance des apports sahariens pour Al, Si, Mn et Fe, et à l'importance des sources de pollution pour Cu, Zn, Pb, le phosphore montrant une origine mixte crustale et de pollution bien partagée. Les sources crustales et de pollution sont toutes suffisamment éloignées du point de prélèvement pour que la matière recueillie ait subi un transport à longue distance. Seule la source mari n e est présente localement. L'étude trajectographique des masses d'air associées à chacune des pluies, confirme à chaque fois la possibilité d'un tel transport, tout en indiquant le caractère presque systématiquement frontal des situations rencontrées. Ainsi, le mélange des polluants en provenance de l'Europe avec les produits de l'érosion éolienne des sols africains se trouve très favorisé dans la zone de front où prend naissance la précipitation. L'étude des balances ioniques et du pH montre alors de manière nette cette incorporation simultanée, dans les gouttes d'eau de pluie, des acides provenant des zones polluées et des composés crustaux (en particulier la calcite) neutralisant cette acidité. Enfin, la partie la plus importante de ce travail concerne la partition entre les phases soluble et insolubl e des éléments choisis. Nous avons pu montrer que certains éléments, comme le phosph o re et le mang a nèse , présentent une fraction d'origine de pollution entièrement soluble se séparant de la fraction crustale très peu soluble, voire insoluble. A l'opposée, l'al u minium e t le fer , d'origine uniquement crustale, sont en équilibre de solubilité avec l e ur hydroxyde situé à la surface des particules solides en suspension, pourvu qu'il ne soit pas entièrement dissous; pour le fer, cet hydroxyde représente en moyenne 15% de sa masse. D'une même f a çon, le c uivre , le zinc et le plomb sont en équilibre d'adsorption-désorption entre la phase aqueuse et des oxydes hydratés de fer, de manganèse ou d'aluminium présents à la surface des particules solides en suspension dans la goutte d'eau de pluie. Ainsi, le devenir des éléments en équilibre dans la goutte de pluie dépendra fortement du milieu récepteur qui, en fixant de nouvelles conditions physico-chimiques, déplacera les équilibres de ces éléments entre les phases solubles et insolubles.
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Kieffer, Bruno. "Pétrologie et géochimie des trapps et des volcans-boucliers d'Ethiopie et du plateau de Kerguelen (LEG ODP183, site 1139)." Phd thesis, Grenoble 1, 2002. http://tel.archives-ouvertes.fr/tel-00688401.
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De nombreuses études sont consacrées aux grandes provinces magmatiques. Cependant, l'architecture de ces provinces et l'origine de la diversité de leurs composants volcaniques restent encore mal connues. Le but majeur de cette thèse a été d'étudier l'architecture, la diversité et l'origine des plateaux à travers deux exemples : Kerguelen et Ethiopie. A Kerguelen, notre recherche a été axée sur la ride Leclaire, à l'extrémité ouest du plateau. Elle nous a permis : (1) de découvrir les roches alcalines les plus anciennes du plateau, (2) de mettre en évidence la présence d'un volcanisme aérien, (3) de démontrer que le panache de Kerguelen n'est pas localisé sous cette ride, enfin (4) de prouver l'absence d'un composant crustal dans la source des laves. En Ethiopie, nous avons montré que la pétrologie et la géochimie des laves des volcan-boucliers et des trapps sous-jacents sont identiques. La transition ne correspond donc pas à un changement de type de magma mais à une évolution physique du système d'alimentation. Les laves qui constituent le plateau éthiopien présentent deux bimodalités : acide-basique et tholéiitique-alcalin. L'analyse géochimique montre que ces laves proviennent d'un panache hétérogène en termes de température et composition. La datation et la cartographie des différentes unités révèlent que le plateau éthiopien est formé de plusieurs centres éruptifs d'âges et de caractères pétro-géochimiques différents. D'un point de vue plus général, les quantités de laves émises sur ces deux plateaux évoluent différemment dans le temps. Le flux de magma dépend de l'activité du panache ainsi que de la vitesse d'ouverture des plaques qui contrôle l'évolution de l'épaisseur de la lithosphère.
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Dixon, Eleanor Tamiko. "Noble gas geochemistry of Icelandic basalts." Phd thesis, 2000. http://hdl.handle.net/1885/148116.
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Jolly, Lauren Cher. "Petrographic and geochemical analysis of the impactite succession in the Eyreville B drill core, Chesapeake Bay impact structure, Virginia, USA." Thesis, 2011. http://hdl.handle.net/10539/10430.
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MSc, Faculty of Science, University of the Witwatersrand, 2011The 35.3 million year old, 85 km diameter, Chesapeake Bay impact structure (CBIS) in Virginia, USA, is one of the best preserved complex marine impact structures on Earth and is associated with the North American tektite strewn field. Three drill cores (Eyreville A, B and C) were obtained from the Chesapeake Bay impact structure during 2005-2006 by the CBIS Deep Drilling Project in conjunction with the International Continental Scientific Drilling Program (ICDP) and the United States Geological Survey (USGS). The drill cores intersected crystalline basement rocks, impactites, and impactrelated and post-impact sediments. This study focuses on the impactite sequence of the Eyreville B drill core. The primary focus has been to examine and understand the conditions and processes involved in the formation of the crater-fill impactite sequence, and the provenance of the impactites, through detailed lithostratigraphic, petrographic and geochemical analysis. The Eyreville B drill core intersected 154 m of impactites between the depths of 1397.16 and 1551.19 m. The impactite sequence is divided into the upper (1397.16 to 1474.05 m) and the lower (1474.05 to 1551.19 m) impactite units. The upper impactites are matrixsupported (23.5 rel% of total clast count) and characterised by suevite, clast-rich impact melt rock and cataclastic gneiss blocks, whereas the lower impactites are clast-supported (19.8 rel% of total clast count) and are dominated by polymict impact breccia and cataclastic gneiss boulders and blocks. The suevites comprise melt and lithic clasts from sedimentary (predominantly shale and sandstone) and igneous (such as granitoid and quartz pegmatoid) target rocks in an unsorted matrix composed of mineral (primarily quartz, feldspar and micas) and lithic clasts. The polymict impact breccias are primarily composed of metamorphic clasts such as phyllite, mica schist and felsic and mafic gneiss, and are largely, but not completely devoid of melt clasts. The majority of clasts in the impactite sequence closely resemble the granitoid, pegmatoid, calc-silicate, amphibolite and mica schist lithologies found in the underlying basement-derived succession and megablocks in the overlying sedimentary clast breccia. Overall, the crystalline (igneous and metamorphic) and sedimentary clasts contribute 62.3 and 20.8 vol%, respectively, of iv the total lithic clast composition which is comparable to 58.2 (crystalline) and 26.0 (sedimentary) vol% for the latest published results. The impactites are generally heterogeneous in terms of their chemical compositions. The impactite samples display enrichment in FeO+MgO in comparison to the target rock lithologies, with smaller abundances of K2O and Na2O, with little to no CaO. Throughout the impactite sequence, the suevites display the largest variety in chemical composition due to the heterogeneity of the clasts. The overall abundance of melt clasts varies from 22.1 vol% (of the total clast population) in the upper impactites to 2.5 vol% (of the total clast population) in the lower impactites. Melt clasts are generally flattened and elongated and display laminar flow structures (schlieren), with fractured terminations. Most melts are highly vesiculated and altered to phyllosilicate minerals. Overall, melt clasts show a general decrease in size with depth. Observations indicate that no coherent melt sheet was intersected; impact melt rock was only noted in the impactite sequence at depths between 1402.02 and 1407.49 m and 1450.22 and 1451.22 m. Melt clasts are heterogeneous in terms of their chemical compositions and are generally SiO2-rich and represent the melting and mixing of different mineral (quartz, feldspar and phyllosilicates) types derived from the target lithologies. This finding is comparable to the observations noted in the recent published literature. On average, 23.6 rel% of all quartz grains in the upper impactite unit display one or more PDF (planar deformation features) sets, with this number decreasing to 13.33 rel% for the lower impactite unit. A general decrease in average shock pressure with depth has been noted, which is consistent with the decrease in other shock features and melt clast abundance from the upper to lower impactites. A maximum of 3 PDF sets in the quartz grains, in the upper impactites, were noted; however, mostly 1 or 2 PDF sets were observed. Diaplectic glass has been noted in the melt clasts and is present predominantly in the upper impactites. No PDFs in feldspar grains have been noted. v A small, low temperature impact-induced hydrothermal system (220 – 300 °C) affected the material within the crater, which is evident from veins and patches of quartz, calcite, secondary phyllosilicate minerals (smectite), zeolites, secondary pyrite and chalcopyrite, as well as other sulphides. The upper and lower impactites show differing petrographic, geochemical and shock characteristics, suggesting that they were formed by different mechanisms. The upper suevites (upper part of the impactite sequence) are composed of fallback debris from the collapsing ejecta plume or curtain, whereas the suevites (S3 and S2) represent a mixture of the ground-surge material and fallback debris from the collapsing ejecta plume. The impact melt rocks are interpreted as either detached remnants of the melt lining the transient crater or piles of melt derived from fallback debris. It is proposed that the lower suevites (S1) and polymict impact breccia represent ground-surge deposits at the base of and behind the advancing ejecta curtain, modified by slumping and mixing of unshocked material from the outer crater walls. The cataclastic gneiss blocks and boulders slumped in from the outer transient crater walls and were incorporated into the ground-surge deposits. This study of the impactite sequence from the Chesapeake Bay impact structure has provided new insights into the formation of the impactite sequence as well as that of the Chesapeake Bay impact structure. Research such as this allows for further understanding and discussions regarding marine cratering processes (impact processes and impact-generated deposits) and emplacement mechanisms for impact craters. Essentially a study such as this provides material for further extensive research into the formation of marine impact craters and comprehensive modelling.
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Gonzalez, Angela M. "Nitrogen-specific gas chromatographic detection by atomic plasma spectral emission. Analytical gas chromatography-mass spectrometry studies of subsurface biomarkers." 1999. https://scholarworks.umass.edu/dissertations/AAI9932315.
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Analysis of nitrogen containing compounds by gas chromatography with atomic emission detection has always been problematic. Nitrogen detection has been customarily done using the 174.53 and 174.27 nm atomic lines, with very limited selectivity and sensitivity. Nitrogen can also be detected using the cyanogen (CN) molecular emission bands at 388 nm. It has been reported that a 100-fold improvement in the selectivity using this line can be reached. Therefore, in the present work, the instrument available in the laboratory was modified to allow the use of the 388 nm line for the nitrogen detection. The modification of the instrument involved the use of a mixture of reagent gases that were optimized to produce the best nitrogen emission using the 388 nm line. Figures of merit of the detection using this line, were evaluated and compared with the commonly used nitrogen line (174 nm) and the carbon detection (193 nm). The dependence of the GC-AED response with the molecular structure of the analyte, and its application in the determination of empirical formula was also evaluated, and its application for analysis of petroleum products. The second part of the present work studied the biomarkers in deep subsurface samples and their relationship with the microbial activity. Little is known of microbial community characteristics at depths larger than 50 m below surface, information that is crucial for the clean up of contaminated underground environments. The use of classical approaches to identify microbiota, often results in the characterization of less than 10% of the biota present when analyzing deep subsurface samples, therefore, the analysis of lipid content in the samples have been proposed. Microorganisms use lipids as constituent of their cell walls or as nutritional sources. Monitoring lipids can be used to develop a picture of how, when, where and under which conditions microbes are active in the subsurface. This research was focussed in the biomarker study of a shale and sandstone from Cerro Negro, New Mexico. Biomarkers were determined to study distribution, concentration and availability of resources that support life and microbial activity and their relationship with geochemical parameters.
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Vengosh, Avner. "Boron isotope geochemistry in the sedimentary environment." Phd thesis, 1990. http://hdl.handle.net/1885/139620.
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"Quality control program for a geochemical laboratory, Department of Geological Sciences, University of Saskatchewan, Canada." Thesis, 2014. http://hdl.handle.net/10388/ETD-2014-09-1708.
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The quality of analytical data produced by geochemical laboratories has become progressively more important as complex decisions concerning the impact of development on the environment Public concern regarding the impact of resource, industrial, and agricultural development is placing greater pressure on the government to protect the environment (Zhou, 2013). The quality of such data is squarely dependent on adherence to quality control programs, which provide guidelines from which high quality, trustworthy data can be generated.
A unique quality control program was developed and implemented at the NSERC-IRC Aqueous and Environmental Geochemistry Laboratory. This program: 1) accommodate samples from unique environments; 2) documents and maintains the high level of confidence in the data produced; 3) provides standard quality control protocols; and 4) ensures the continued training of staff. The evaluation of data produced during 2013 revealed the strengths and weaknesses of the laboratory methods through comparison with data quality objectives.
The data produced by the laboratory during 2013 was evaluated and quality confirmed. It was determined that the results produced met the high standards required by the data quality objectives, with a few minor exceptions. The quality objectives were based on the end use of the data and consideration regarding the complex nature of the water samples collected from diverse geologic media. There was increased variability of results near the method detection limit of selenium, cadmium, and arsenic, although they still meet to standards required for water quality investigations. Investigations into variabilities will include re-evaluation of detection limits, identification of the source of discrepancy between the methods, and possible matrix interference. Protocols will continue to be monitored and changes to methods made when objectives are not achieved or there are changes in laboratory staff, equipment, or the specific requirements of the studies the laboratory supports.
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Townsend, Gabrielle Nicole. "A geochemical and petrological study of the crystalline basement and associated megablocks of the Eyreville-B drillcore, Chesapeake Bay impact structure, USA." Thesis, 2015. http://hdl.handle.net/10539/17653.
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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2015.The ca. 36 Ma Chesapeake Bay impact event on the east coast of Virginia, USA, formed an 85 km complex crater in Cretaceous to Eocene sediments and underlying crystalline basement rocks belonging to the Appalachian orogen. Appalachian rocks are well exposed along the Appalachian Mountains to the west, however, little is known of the basement along the Atlantic Coastal Plain owing to the covering sedimentary sequence. This study investigates the crystalline rocks intersected by the 2006 ICDP (International Continental Scientific Drilling Program) – USGS (United States Geological Survey) drilling of the Chesapeake Bay impact structure (CBIS) on the Eyreville Farm near Cape Charles, Virginia. The crystalline rocks of the Eyreville-B borehole core are found in the lower basement-derived section (between 1551.19 m and 1766.32 m depth), in the amphibolite megablock (between 1376.38 m and 1389.35 m depth) and in the upper granite megablock (between 1095.74 m and 1371.11 m depth). The lower basement-derived section consists of foliated metasediments, which include mica schist, amphibolite and calc-silicate rock, and coarse-grained to pegmatitic granite. The amphibolite megablock is a black to dark grey to dark green, fine- to medium-grained, locally foliated, relatively homogenous, lithic block. The upper granite megablock is divided into gneissic and massive varieties, with a minor component of biotite schist xenoliths. The crystalline rocks contain foliations and related structures, fractures and breccias, microstructures and porphyroblast microstructures; however, none of the three lithic blocks is in situ and, consequently, structural measurements cannot be fully interpreted tectonically. Mineral assemblages and microstructural evidence in the mica schists suggest the rocks in the lower basement-derived section experienced a syn-D1 amphibolite facies peak metamorphic event (M1a) followed by retrograde metamorphic conditions (M1b) limited to D1b mylonitic and D2 brittle deformation. Similar metamorphic conditions in the upper megablocks suggest that the three sections likely formed part of a single metamorphic terrane. iv Geochemistry in the lower basement-derived mica schists revealed a strong intermediate igneous provenance, whereas the upper megablock biotite schist xenoliths showed a quartzose sedimentary provenance; the precursors to both appear to have been deposited in active continental margin settings. The lower basement-derived amphibolite appears to be derived from a sedimentary source. The precursor to the upper amphibolite megablock, on the other hand, was probably a tholeittic gabbro generated in an island arc setting. The peraluminous, S-type nature of the lower basement-derived granite suggests it was most likely generated in a within-plate tectonic setting. In contrast, the massive and gneissic granites from the upper megablock are metaluminous, I-type granites that were most likely generated in a syn-collisional environment. Metamorphic conditions of the M1 event were constrained using mineral assemblages mainly from the lower basement-derived section, which limited the X(H2O) value to 0.8, P to >0.4 GPa and the T range to 600-670°C. Using the 0.4 GPa pressure constraint, Zr-in-rutile thermometry revealed a peak metamorphic temperature for the M1 event of 606 ± 18°C, which is consistent with mid-amphibolite facies metamorphism. These estimates suggest a very steep geothermal gradient approaching ~44°C/km. Rutile U/Pb geochronology revealed that the M1 event recorded in the lower basement-derived metasediments occurred at 259 ± 13 Ma, with Ar/Ar geochronology indicating the cooling path through to greenschist metamorphic conditions. Zircon U/Pb SHRIMP geochronology performed by Horton et al. (2009b) on the massive and gneissic megablock granites dated their crystallisation ages at 254 ± 3 Ma and 615 ± 7 Ma, respectively, with the former age in agreement with the rutile U/Pb peak metamorphism results from the lower basement-derived section. These ages, together with petrography, structural observations, geochemistry and geothermobarometry suggests that the amphibolite and granite megablocks form part of the same metamorphic terrane as the lower basement-derived section and that the D1 and M1 events recorded in the lower basement-derived section and upper megablocks of the Eyreville-B borehole core likely occurred during the late stages of the Alleghanian orogeny. v Based on mineralogy, geochemistry, metamorphic grade and structural evidence, comparisons with the neighbouring terranes within the Appalachian basement beneath the Atlantic Coastal Plain sediments suggest that the lower basement-derived and upper amphibolite and granite megablocks of the Eyreville-B borehole core most likely formed part of the Hatteras terrane prior to the Chesapeake Bay impact event. This terrane, together with 5 other terranes, forms part of the Carolina Zone, a peri-Gondwanan micro-continent formed by the amalgamation of magmatic arcs during the Penobscottian and Taconian orogenies, which was then accreted onto the Laurentian margin during the Salinic and Acadian orogenies.
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Abraham, Kathrin [Verfasser]. "Variation of stable silicon isotopes : analytical developments and applications in Precambrian geochemistry / Kathrin Abraham." 2010. http://d-nb.info/1004191049/34.
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Plaza, Toledo Meralis. "Natural rock drainage associated with unmined porphyry copper deposits in the Río Grande de Arecibo watershed, Puerto Rico /." 2005. http://grad.uprm.edu/tesis/plazatoledo.pdf.
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Matsumoto, Takuya. "Noble gas geochemistry of mantle-driven xenoliths from the newer volcanics, southeastern Australia." Phd thesis, 1997. http://hdl.handle.net/1885/149774.
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"A New Analytical Method for Measuring Hydrogen Isotopes Using GC-IRMS: Applications to Hydrous Minerals." Master's thesis, 2011. http://hdl.handle.net/2286/R.I.9240.
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abstract: A new analytical method is proposed for measuring the deuterium to hydrogen ratio (D/H) of non-stoichiometric water in hydrous minerals via pyrolysis facilitated gas-chromatography - isotope ratio mass spectrometry (GC-IRMS). Previously published analytical methods have reported a poorly understood nonlinear dependence of D/H on sample size, for which any accurate correction is difficult. This sample size effect been variously attributed to kinetic isotope fractionation within the mass spectrometer and peripheral instruments, ion source linearity issues, and an unstable H_3^+-factor or incorrect H_3^+-factor calculations. The cause of the sample size effect is here identified by examinations of individual chromatograms as well as bulk data from chromatographic peaks. It is here determined that it is primarily an artifact of the calculations employed by the manufacturer's computer program, used to both monitor the functions of the mass spectrometer and to collect data. Ancillary causes of the sample size effect include a combination of persistent background interferences and chromatographic separation of the isotopologues of molecular hydrogen. Previously published methods are evaluated in light of these findings. A new method of H_3^+-factor and D/H calculation is proposed which makes portions of the Isodat software as well as other published calculation methods unnecessary. Using this new method, D/H is measured in non-stoichiometric water in chert from the Cretaceous Edwards Group, Texas, as well as the Precambrian Kromberg Formation, South Africa, to assess hydrological conditions as well as to estimate the maximum average surface temperature during precipitation of the chert. Data from Cretaceous chert are consistent with previously published data and interpretations, based upon conventional analyses of large samples. Data from Precambrian chert are consistent with maximum average surface temperatures approaching 65°C during the Archean, instead of the much lower temperatures derived from erroneous methods of sample preparation and analysis. D/H is likewise measured in non-stoichiometric water in silicified basalt from the Precambrian Hooggenoeg Complex, South Africa. Data are shown to be consistent with D/H of the Archean ocean similar to present day values.Dissertation/Thesis
M.S. Geological Sciences 2011
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Patterson, Desmond Bruce. "Noble gas geochemistry of selected basalts and andesites : New Zealand, Tonga-Kermadec and Vanuatu." Phd thesis, 1992. http://hdl.handle.net/1885/140350.
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Pautler, Brent Gregory. "Novel Analytical Approaches for the Characterization of Natural Organic Matter in the Cryosphere and its Potential Impacts on Climate Change." Thesis, 2013. http://hdl.handle.net/1807/43704.
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Climate change is predicted to be the most pronounced in high latitude ecosystems, however very little is known about their vulnerability to the projected warmer temperatures. In particular, natural organic matter (NOM) in the high latitude cryosphere which includes dissolved organic matter (DOM) and cryoconite organic matter (COM) from glaciers and soil organic matter (SOM) in permafrost, is highly susceptible to climate change which may lead to severe consequences on both local and global carbon biogeochemical cycles. Examination of DOM in
glacier ice by a novel 1H nuclear magnetic resonance (NMR) water suppression pulse sequence at its natural abundance revealed and quantified the composition and the organic constituents in ice samples from Antarctica. 1H NMR spectra of samples from several glaciers were acquired and compared to the dominant fluorescent DOM fraction. This comprehensive approach showed that glacier ice DOM was mainly composed of small, labile biomolecules associated with microbes. Examination of the organic debris found on glacier surfaces (COM) from both Arctic and Antarctic glaciers were determined to be derived from microbes. Samples from Arctic
glaciers were more chemically heterogeneous with small inputs of plant-derived material
detected after targeted extractions. Therefore the COM carbon composition was determined to be dependent on the local glacier environment, suggesting a site specific contribution to the carbon
cycle. Finally, the distribution of extracted branched glycerol dialkyl glycerol tetraether (GDGT)microbial membrane lipids and the deuterium incorporation of plant-wax n-alkane biomarkers extracted from dated permafrost SOM (paleosols) were independently applied for Canadian Arctic climate reconstruction during the last glacial maximum. Overall, the branched GDGT based temperature reconstructions from the Arctic paleosols reconstruct higher temperatures, likely when bacterial activity was optimal. The deuterium composition of the C29 n-alkane plant lipids appears to integrate an average annual signal. Further analysis by both non-selective NMR spectroscopic and targeted biomarker techniques on these paleosol samples revealed that the major vegetative sources from this paleoecosystem originated from woody and non-woody angiosperms. This thesis demonstrates several novel analytical characterization techniques, along with the major sources and composition of NOM in the cryosphere while demonstrating its use in paleoclimate applications.
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Alcott, Lorraine J. "Distributions of rare earth elements and other trace elements within unmineralized portions of the Bonneterre Formation, southeast Missouri." 1985. http://hdl.handle.net/2097/27388.
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Fourie, Pieter Hugo. "Provenance and Paleotectonic setting of the Devonian Bokkeveld Group, Cape Supergroup, South Africa." Thesis, 2012. http://hdl.handle.net/10210/4331.
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M.Sc.The Lower Devonian Bokkeveld Group is the Middle unit of the tripartite Cape Supergroup, which outcrops along the western, southern and eastern coastline of South Africa. A well-established sedimentary and stratigraphic understanding of the Bokkeveld Group allowed for geochemical and geochronological investigation in order to gain insight into the provenance characteristics, as well as the paleotectonic environment of the provenance areas. In order to observe any changes within the Bokkeveld Basin, complete profiles for geochemical investigation were sampled in the western, southern and eastern parts of the basin, and compared. Major and trace element patterns suggest that the western part of the basin received detrital input from felsic, magmatically evolved, and possibly alkaline sources, and that the sediment was highly recycled before deposition. Furthermore, the geochemistry suggests that the western part of the basin experienced “passive margin” type sedimentation. The geochemistry of the southern basin, in contrast, suggests input from less evolved, non-alkaline sources, and predicts sedimentation under “active margin” conditions for the lower part of the group. The eastern basin is geochemically intermediate between the western and southern basins. Zircon populations for the three parts of the basin further suggest that sources of different ages fed the three parts of the basin. The zircon population of the western basin suggests that the Namaqua Natal Belt (Mesoproterozoic) and Neoproterozoic cover successions were the major source of detritus, with only minor input from Paleozoic sources. The eastern basin also appears to have sourced mainly Namaquan aged material as well as Neoproterozoic material, with no Paleozoic input. The southern basin has a remarkably different zircon population, with the majority of grains being Paleozoic in age, and only a few Neoproterozoic and Mesoproterozoic grains. Furthermore, many of the grains are younger than any known source-rocks on the Kalahari Craton, and thus allude to input from an extra-Kalahari source into the southern part of the basin. The youngest grain from the southern basin overlaps with the established depositional age of the Bokkeveld Group, suggesting some syn-depositional or briefly pre-depositional magmatic activity in the source area(s) of the southern basin, as predicted by the geochemistry. The complete lack of zircon ages older than the Namaqua Natal Belt (Mesoproterozoic), would suggest that the Archean to Paleoproterozoic inner part of the Kalahari Craton, the Kaapvaal Craton, was not sourced by the Bokkeveld Group. This is most likely due to the Namaqua Natal Belt having served as a large east-west trending morphological divide during Bokkeveld deposition, preventing transport of detritus from the craton interior. Remarkably, this would suggest that the Namaqua Natal Mountain Range must have survived erosion and persisted as a morphological boundary for ca. 600 Ma to serve as the major source of detritus for the Bokkeveld Group. Even an extensive, craton-fringing sedimentary cover-succession such as the Bokkeveld Group, may thus not provide a “detrital fingerprint” of the craton interior, and paleogeographical implications must be taken into consideration during provenance studies. Paleocurrent directions for the Bokkeveld Group indicate a west to east transport direction in the southern part of the basin, and as such, a western, extra-Kalahari source, most likely the Rio de La Plata Craton and surrounds, is expected to have been the source of both the young Paleozoic zircons, as well as undifferentiated material as revealed in the geochemistry.
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"Microanalysis for Oxygen Fugacity by Secondary Ion Mass Spectrometry." Master's thesis, 2019. http://hdl.handle.net/2286/R.I.53643.
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abstract: Oxygen fugacity (ƒO2) is a thermodynamic variable used to represent the redox state of a material or a system. It is equivalent to the partial pressure of oxygen in a particular environment corrected for the non-ideal behavior of the gas. ƒO2 is often used to indicate the potential for iron to occur in a more oxidized or reduced state at a particular temperature and pressure in a natural system. Secondary ion mass spectrometry (SIMS) is a powerful analytical instrument that can be used to analyze elemental and isotopic compositional information about microscopic features within solid materials. SIMS analyses of the secondary ion energy distribution of semi-pure metals demonstrate that the energy spectrum of individual mass lines can provide information about alterations in its surface environment.
The application of high-resolution (see Appendix C) energy spectrum calibrations to natural ilmenite led to the investigation of zirconium (90Zr+) and niobium (93Nb+) as potential indicators of sample ƒO2. Energy spectrum measurements were performed on an array of ilmenite crystals from the earth’s upper mantle retrieved from kimberlites and from a reduced meteorite. In all studied materials, variability in the peak shape and width of the energy spectra has been correlated with inferred sample ƒO2. The best descriptor of this relationship is the full-width at half-maximum (FWHM; see Appendix C) of the energy spectra for each sample. It has been estimated that a 1eV change in the FWHM of 93Nb+ energy spectra is roughly equivalent to 1 log unit ƒO2. Simple estimates of precision suggest the FWHM values can be trusted to 1eV and sample ƒO2 can be predicted to ±1 log unit, assuming the temperature of formation is known.
The work of this thesis also explores the applicability of this technique beyond analysis of semi-pure metals and ilmenite crystals from kimberlites. This technique was applied to titanium oxides experimentally formed at known ƒO2 as well as an ilmenite crystal that showed compositional variations across the grain (i.e., core to rim chemical variations). Analyses of titanium oxides formed at known ƒO2 agree with the estimation that 1 eV change in the FWHM of 93Nb+ is equivalent to ~1 log unit ƒO2 (in all cases but one); this is also true for analyses of a natural ilmenite crystal with compositional variations across the grain.Dissertation/Thesis
Masters Thesis Geological Sciences 2019
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Pass, HE. "Breccia-hosted chemical and mineralogical zonation patterns of the northeast zone, Mt. Polley Cu-Ag-Au alkalic porphyry deposit, British Columbia, Canada." Thesis, 2010. https://eprints.utas.edu.au/10820/1/Pass_whole_thesis.pdf.
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The Mt. Polley alkalic Cu-Ag-Au porphyry was emplaced in the late Triassic to early Jurassic Quesnellia island-arc terrane of the Canadian Cordillera. In the Central Quesnel Belt, Middle Triassic fine-grained oceanic sediments ± limestone were overlain by a thick pile of Late Triassic submarine, alkalic basaltic to andesitic volcanics (Nicola Group), with related subvolcanic intrusions and minor limestones of Late Triassic age. The Mt. Polley Complex is a 6.0 km long by 3.5 km wide, north-northwest-trending, composite alkalic intrusive (and breccia) complex; one of several that are scattered along the length of this terrane, making British Columbia the type location for Au-enriched alkalic porphyry deposits. The Mt. Polley Complex contains silica-undersaturated to silica-saturated pyroxenites, diorites and syenites, but is dominated by monzonites, monzodiorites, and associated breccia bodies, all of which were emplaced during the final stages of arc magmatism, between 209.4 Ma and 195.4 Ma. Mineralization occurred between 209 and 204 Ma. A new model Pb age of 207.8 ± 1.8 Ma for a galena vein is consistent with these ages.
The NEZ is an alkalic Cu-Ag-Au porphyry deposit hosted by the Mt. Polley Complex. Ore is distinctly higher grade than in other ore zones at Mt. Polley, with average Cu grades at 0.8–1.0 percent and Au grades 0.19–0.29 g/t. Mineralization and alteration mostly occurred during magmatic-hydrothermal breccia formation. Chalcopyrite and bornite occur primarily as coarse- to fine-grained breccia cement, with lesser disseminations, veins and replacements. Bornite-rich, pyrite-deficient high-grade zones of mineralization (>1% Cu, up to >5% Cu locally) occur within broader chalcopyrite-rich domains (Cu grades of 0.3 to 1.0 %). Pyrite is the dominant sulfide on the deposit periphery (up to 1–2% locally).
There were five major mineralization and alteration events in the NEZ: 1) early-stage (pre-breccia), 2) main-stage (syn-breccia), 3) post-brecciation late-stage mineralization, 4) barren intrusions, veins and vein breccia, and 5) epithermal-style veins. Main stage alteration and mineralization assemblages are zoned vertically and laterally through the breccia body. Magmatic-hydrothermal brecciation focused the high temperature mineralizing fluids, forming a core of potassic alteration (K-feldspar-magnetite-albite-calcite ± biotite ± augite ± anhydrite ± epidote and Cu-Fe-sulfides) surrounded by a halo of propylitic alteration (pyrite-chlorite-epidote ± albite ± sericite). Calc-potassic (garnet ± epidote) and sodic (albite) alteration assemblages are variably abundant within the broader domains of potassic and propylitic alteration. Alteration minerals are consistent with temperatures >300°C and near-neutral to alkalic pH fluids during stages 1, 2 and 3. Acidic and lower temperature fluids were associated with stages 4 and 5.
Laser-ablation ICP-MS analyses of sulfide trace element contents of the NEZ have shown bornite is enriched in Ag (average 913 ppm), Bi and Se. Chalcopyrite is enriched in Pb, Zn and Se, with Zn concentrations increasing and Pb concentrations decreasing from the centre of the deposit to its margins. Pyrite is enriched in Cu, Zn, Cd, Co, Ni, Se, Te and Au with these elements substituted into the pyrite structure or evenly disseminated as nano-particles. Pyrite contains abundant micro-inclusions of chalcopyrite, galena,
sphalerite, electrum and tellurides. Gold contents were found to be 1–3 orders of magnitude higher in pyrite (0.011–4.32 ppm, plus one outlier of 483.2 ppm) than in chalcopyrite (0.050–1.29 ppm). Gold was mostly below detection limits in bornite. Gold, Pd- and Pt-bearing inclusions were primarily detected in pyrite on the fringes of the deposit. This contradicts the assay data that shows high gold grades are associated with areas rich in bornite and chalcopyrite. This implies that the Au in the high-grade ore zones does not occur in Cu-sulfides, but in another phase, possibly electrum.
The \(δ^{34}S_{sulfide}\) isotopic compositions of main- and late-stage chalcopyrite, pyrite and bornite range from -7.1 to +1.4 per mil, with most between -3 and -4 per mil. Sulfur isotopic compositions of anhydrite and gypsum were between +6.2 and +9.8 per mil, with two outliers of +13.6 and +14.0 per mil. These values, together with the presence of hematite, are consistent with an oxidized (sulfate predominant), high-temperature (>400°C) magmatic-hydrothermal fluid. Limited sulfide geothermometry indicates that ore precipitated at temperatures from ~ 480° to ~ 250°C. The `δ^(34)S` values of main-stage sulfides define zonation patterns across the deposit, from low `δ^(34)S` values in the core to higher `δ^(34)S` values near the deposit periphery. Changes in redox conditions, pH changes, cooling, and water-rock interaction are concluded to have been important processes of ore formation and hydrothermal alteration in the NEZ.
Hydrothermal calcite occurs throughout the paragenesis, and several processes may have contributed to its precipitation, including boiling, `CO_2` degassing, pH increase, and water-rock interaction. Calcite `δ^(13)C` values range from -0.2 to -10.5 per mil (average -3.0 ‰), and `δ^(18)O` values from +4.0 to +20.9 per mil (average +15.4 ‰). The C-O isotopic values are not consistent with simple precipitation from a “normal” magmatically-derived source hydrothermal fluid. Enriched `δ^(13)C` values suggest the involvement of a heavy carbon source, such as limestone or seawater. However, `δ^(18)O` isotopic data preclude the involvement of meteoric or seawater in the formation of the NEZ, until stage 4.
Lead isotopic data suggest mixing of mantle and crustal sources during mineralization. Main-stage chalcopyrite, pyrite and late-stage galena have \(^{206/204}Pb\) values of 18.77–18.92, \(^{207/204}Pb\) of 15.56–15.59 and \(^{208/204}Pb\) of 38.22–38.32. Strontium isotopic data (0.70331 to 0.70371) provide evidence of a strongly depleted mantle source of Sr with minor crustal input. Epsilon Nd values for main-stage apatite range between +5.9 and +6.5, also indicating a depleted mantle source. Stage 5 carbonate \(^{206/204}Pb\) values of 18.96–19.04, \(^{207/204}Pb\) of 15.57–15.59 and \(^{208/204}Pb\) of 38.26–38.36, from epithermal-textured veins suggest that telescoping of an epithermal environment into the NEZ occurred ~100 m.y. after breccia formation.
The stable and radiogenic isotopic data provide evidence that the silica-undersaturated alkalic Mt. Polley Complex formed due to carbonate assimilation prior to mineralization. This process can explain both the `δ^(13)C-δ^(18)O` isotopic data and the silica-undersaturated composition of the magmatic-hydrothermal system. The CO2 released during assimilation of carbonate could have promoted magmatic-hydrothermal brecciation, thereby leading to high-grade ore formation. Silica-undersaturated alkalic porphyry systems may preferentially form in arc terranes built on a carbonate-bearing substrate or where carbonate platforms are subducted.
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Pretorius, Donavan Johannes. "Characterisation and beneficiation of coal from the New Vaal Colliery, Sasolburg-Vereeniging Coalfield, South Africa, through the application of automated mineralogy." Thesis, 2015. http://hdl.handle.net/10210/15079.
Full textAbstract:
M.Sc. (Geology)The purpose of this study was to assess the MLA’s ability to characterise (e.g. modal mineralogy, elemental assay, particle size distribution, particle density distribution and mineral associations) a coal product from New Vaal Colliery, with the aim to determine any liberation and beneficiation characteristics. In general the MLA assessment on coal is comparatively new and novel, especially at Spectrum (University of Johannesburg), hence research in this regard is required. For the first time New Vaal coal product was characterised with the MLA 600 FEG SEM. The coal product supplied to Lethabo Power Station for the study’s samples, consisted of Top Seam and Middle Seam coal from New Vaal Colliery which is located in the Cornelia subbasin of the Vereeniging-Sasolburg coalfield, South Africa. The proximate analysis characterised the coal as a high-ash (42.25% air-dried) and low calorific value (13.92 MJ/kg air-dried) product. Chemically SiO2 was the most abundant oxide followed by Al2O3 for the XRF analysis, which was mostly derived from the abundant kaolinite clay mineral (determined by petrography, XRD and MLA analysis). Mineralogically inertinite was the most abundant coal maceral encountered during the petrographic analysis. With geochemical characterisation, chalcophile, siderophile, lithophile and radioactive trace elements were found to be mostly comparable to the global average.
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Ashworth, Luisa. "Mineralised pegmatites of the Damara Belt, Namibia: fluid inclusion and geochemical characteristics with implications for post-collisional mineralisation." Thesis, 2014. http://hdl.handle.net/10539/15064.
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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy, Johannesburg 2014Namibia is renowned for its abundant mineral resources, a large proportion of which are hosted in the metasedimentary lithologies of the Damara Belt, the northeast-trending inland branch of the Neoproterozoic Pan-African Damara Orogen. Deposit types include late- to post-tectonic (~ 523 – 506 Ma) LCT (Li-Be, Sn-, and miarolitic gem-tourmalinebearing) pegmatites, and uraniferous pegmatitic sheeted leucogranites (SLGs), which have an NYF affinity. Fluid inclusion studies reveal that although mineralization differs between the different types of pegmatites located at different geographic locations, and by extension, different stratigraphic levels, the fluid inclusion assemblages present in these pegmatites are similar; thus different types of pegmatites are indistinguishable from each other based on their fluid inclusion assemblages. Thorough fluid inclusion petrography indicated that although fluid inclusions are abundant in the pegmatites, no primary fluid inclusions could be identified, and rather those studied are pseudosecondary and secondary. Fluid inclusions are aqueo-carbonic (± NaCl), carbonic, and aqueous. It is proposed that all of the pegmatites studied share a similar late-stage evolution, with fluids becoming less carbonic and less saline with the progression of crystallisation. Oxygen isotope ratios allow the discrimination of different pegmatites into two groups, Group A (Sn-, Li-Sn-, and gem-tourmaline-bearing LCT pegmatites), and Group B (Li-Bebearing LCT, and U-bearing NYF pegmatites). Group A pegmatites have O-isotope ratios ranging from 11 to 13 ‰ suggesting that they have an I-type affinity. These values are, however, elevated above those of typical I-type granites (7 - 9 ‰), indicating either a postemplacement low-temperature exchange with meteoric fluid, high-temperature hydrothermal exchange with δ18O country rocks during emplacement, or the derivation of these pegmatites from a non-pelitic/S-type metaigneous source. Group B pegmatites have higher δ18O ratios (δ18O = 15 - 16 ‰), indicative of their S-type affinity, and their derivation from metapelitic source rocks. δD values of all the pegmatites range from -40 ‰ to -90 ‰ indicating that the pegmatitic fluids are primary magmatic with a metamorphic fluid component. Trends in the trace element concentrations of both Group A and Group B pegmatites are very similar to each other, making the two groups indistinguishable from each other on this basis. The Damaran pegmatites also share similar geochemical trends with their country rocks. There is, however, no direct field evidence to suggest that the pegmatites were derived from the in situ anatexis of the country rocks. It is more likely that anatexis occurred some distance away from where the pegmatites were ultimately emplaced, and that the melts migrated and were finally emplaced in pre-existing structures, possibly formed during Damaran deformation. O-isotope and Ti-in-quartz geothermometry indicate that Damaran pegmatites can be subdivided into two groups based on their crystallisation temperatures. LCT pegmatites crystallised at temperatures ranging from ~ 450 - 550 ºC, while the NYF pegmatites crystallised at higher temperatures, ranging from 630 - 670 ºC. It is important to note that the subdivision of pegmatites in Groups A and B based on their O-isotope systematics does not correspond with their subdivision into the LCT and NYF pegmatite families according to their crystallisation temperatures. In addition to clarifying aspects of the emplacement and evolution of the Damaran pegmatites, this study points out that there are several discrepancies in the current classification schemes of pegmatites. It shows that in addition to the problems encountered when trying to distinguish between LCT and NYF pegmatites based on their mineralogy, they also cannot truly be distinguished from each other using their geochemical and isotopic characteristics, or their tectonic settings. It is tentatively proposed that crystallisation temperature be considered as an alternative or additional characteristic in the classification of pegmatites, and that it be considered on a regional scale rather than only in the evaluation of the highly evolved end-members of a pegmatite swarm.
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Tailby, Nicholas David. "New experimental techniques for studying : (i) trace element substitution in minerals, and (ii) determining S-L-V relationships in silicate-H2O systems at high pressure." Phd thesis, 2009. http://hdl.handle.net/1885/149676.
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Ti site occupancy in zircon (ZrSiO{u2074}) is fundamental to thermobarometry because substitution mechanisms control Ti content-temperature relations. Described here are the results of three independent methods used to demonstrate that Ti predominately substitutes for Si and not Zr in zircon.
Zircons were synthesized from oxide powders held in a Na{u2082}WO{u2084} flux at 1 bar and 1,100-1,400 {u00B0}C. Fully buffered experiments run at 1,300 {u00B0}C show zircons equilibrated with rutile + cristobalite have Ti contents (1201 ppm) nearly half that of zircons equilibrated with srilankite + tetragonal zirconia (2640 ppm). The lower Ti content of zircons produced under silica-saturated conditions indicates that Ti substitution predominately occurs on the Si site. Moreover, the higher Ti contents of silica-saturated experiments at 1 bar (1201 ppm), relative to those at 10 kbar (457 ppm, Ferry and Watson, 2007), indicate a substantial pressure effect on Ti solubility in zircon (correcting for different silica species present).
Measured Ti K-a edge X-ray Absorption Near Edge Structure (XANES) spectra of synthetic zircons show energies and normalized intensities akin to those seen among tetrahedrally coordinated Ti-bearing standard minerals, strongly suggesting that Ti occupies the Si site. Density functional theory (DFT) calculations confirm that Ti substitution is most likely to occur on the Si site and predict a Ti-O bond length of 1.797 {u00C5} (compared to an average of 2.160 A for substitution on the Zr site), in excellent agreement with X-ray Absorption Fine Structure (EXAFS) spectra of experimentally grown zircons which indicate a value of 1.76(1) {u00C5}. The software FEFF8.4 was used to simulate XANES spectra from the defect structures determined by OFT for Ti substituting on both the Si and Zr sites. The predicted spectrum for Ti on the Si site reproduces all the key features of the experimental zircon spectra, whereas Ti on the Zr site is markedly different. All applied methods confirm that Ti predominately substitutes for Si in zircon. Consequently, the Ti content of zircon is not only a function of temperature, but increases with decreasing silica activity. Because elements that activate or quench cathodoluminescence (CL) in zircon are incorporated into the Zr site, a decoupling of CL signal and Ti distribution (which occurs on the Si site in zircon) is expected. This hypothesis has been verified by a systematic CL-trace element study of natural and experimental zircon.
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"Fluorescent Dissolved Organic Matter in Yellowstone National Park Hot Springs." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.57183.
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abstract: I present for the first time a broad-scale assessment of dissolved organic matter in the continental hot springs of Yellowstone National Park. The concentration of dissolved organic carbon in hot springs is highly variable, but demonstrates distinct trends with the geochemical composition of springs. The dissolved organic carbon concentrations are lowest in the hottest, most deeply sourced hot springs. Mixing of hydrothermal fluids with surface waters or reaction with buried sedimentary organic matter is typically indicated by increased dissolved organic carbon concentrations. I assessed the bulk composition of organic matter through fluorescence analysis that demonstrated different fluorescent components associated with terrestrial organic matter, microbial organic matter, and several novel fluorescent signatures unique to hot springs. One novel fluorescence signature is observed exclusively in acidic hot springs, and it is likely an end product of thermally-altered sedimentary organic matter. This acid-spring component precipitates out of solution under neutral or alkaline conditions and characterization of the precipitate revealed evidence for a highly condensed aromatic structure. This acid-spring component serves as a reliable tracer of acidic, hot water that has cycled through the subsurface. Overall, dissolved organic carbon concentrations and fluorescent features correlate with the inorganic indicators traditionally used to infer spring fluid mixing in the subsurface. Further, the fluorescence information reveals subtle differences in mixing between fluid phases that are not distinguishable through classic inorganic indicator species. My work assessing dissolved organic carbon in the Yellowstone National Park hot springs reveals that the organic matter in hydrothermal systems is different from that found in surface waters, and that the concentration and composition of hot spring dissolved organic matter reflects the subsurface geochemical and hydrological environment.Dissertation/Thesis
Doctoral Dissertation Chemistry 2020