Дисертації з теми "REE geochemistry"
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Zhong, Shaojun. "Precipitation kinetics and partitioning of rare earth elements (REE) between calcite and seawater." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41198.
Повний текст джерелаAs a consequence of solute interactions in solution and at the growing mineral surface, the calcite precipitation mechanism in seawater is complex. It is dominated by the following reversible overall reaction: $ rm Ca sp{2+}+CO sbsp{3}{2-} rightleftharpoons CaCO sb3.$ A kinetic expression is proposed which describes the precipitation rate according to this reaction. A partial reaction order of 3 with respect to CO$ sb3 sp{2-}$ is obtained.
REE have a strong affinity for calcite and substitute for Ca$ sp{2+}$. REE partition coefficients in calcite overgrowths were calculated from their concentrations in the overgrowths and their parent solutions using a non-thermodynamic homogeneous model. The concentrations were determined by chelation and gradient ion chromatography (CGIC) using a revised procedure. REE partition coefficients decrease gradually with increasing REE atomic number. They are sensitive to changes in (REE): (Ca$ sp{2+}$) and the presence of O$ sb2$ in solution, but unaffected by the precipitation rate, $ rm lbrack CO sb3 sp{2-} rbrack$ or Pco$ sb2$ of the solution. The partitioning behaviour of REE is negatively correlated to the solubility of their respective carbonates and influenced by speciation, adsorption, and subsequent surface reactions (e.g., dehydration).
Ramirez-Caro, Daniel. "Rare earth elements (REE) as geochemical clues to reconstruct hydrocarbon generation history." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/16871.
Повний текст джерелаDepartment of Geology
Matthew Totten
The REE distribution patterns and total concentrations of the organic matter of the Woodford shale reveal a potential avenue to investigate hydrocarbon maturation processes in a source rock. Ten samples of the organic matter fraction and 10 samples of the silicate-carbonate fraction of the Woodford shale from north central Oklahoma were analyzed by methods developed at KSU. Thirteen oil samples from Woodford Devonian oil and Mississippian oil samples were analyzed for REE also. REE concentration levels in an average shale range from 170 ppm to 185 ppm, and concentration levels in modern day plants occur in the ppb levels. The REE concentrations in the organic matter of the Woodford Shale samples analyzed ranged from 300 to 800 ppm. The high concentrations of the REEs in the Woodford Shale, as compared to the modern-day plants, are reflections of the transformations of buried Woodford Shale organic materials in post-depositional environmental conditions with potential contributions of exchanges of REE coming from associated sediments. The distribution patterns of REEs in the organic materials normalized to PAAS (post-Archean Australian Shale) had the following significant features: (1) all but two out of the ten samples had a La-Lu trend with HREE enrichment in general, (2) all but two samples showed Ho and Tm positive enrichments, (3) only one sample had positive Eu anomalies, (4) three samples had Ce negative anomalies, although one was with a positive Ce anomaly, (5) all but three out of ten had MREE enrichment by varied degrees. It is hypothesized that Ho and Tm positive anomalies in the organic materials of the Woodford Shale are reflections of enzymic influence related to the plant physiology. Similar arguments may be made for the Eu and the Ce anomalies in the Woodford Shale organic materials. The varied MREE enrichments are likely to have been related to some phosphate mineralization events, as the Woodford Shale is well known for having abundant presence of phosphate nodules. The trend of HREE enrichment in general for the Woodford Shale organic materials can be related to inheritance from sources with REE-complexes stabilized by interaction between the metals and carbonate ligands or carboxylate ligands or both. Therefore, a reasonable suggestion about the history of the REEs in the organic materials would be that both source and burial transformation effects of the deposited organic materials in association with the inorganic constituents had an influence on the general trend and the specific trends in the distribution patterns of the REEs. This study provides a valuable insight into the understandings of the REE landscapes in the organic fraction of the Woodford Shale in northern Oklahoma, linking these understandings to the REE analysis of an oil generated from the same source bed and comparing it to oil produced from younger Mississippian oil. The information gathered from this study may ultimately prove useful to trace the chemical history of oils generated from the Woodford Shale source beds.
Sahlström, Fredrik. "Ore Petrography and Geochemistry of some REE-bearing Fe-oxide Assemblages from the Idkerberget Deposit, Bergslagen, Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-182875.
Повний текст джерелаVarphögar av apatitjärnmalm av Kirunatyp ifrån järnmalmsbrytning i Bergslagen, Sydcentrala Sverige, innehåller förhöjda halter av sällsynta jordartsmetaller. Ett projekt vid Uppsala Universitet undersöker förekomster av sällsynta jordartsmetaller och andra kritiska element i varphögar bland annat från apatitjärnmalmer. I denna studie har prover från ett av Bergslagens apatitjärnmalmsfält, Idkerberget, undersökts geokemiskt och petrografiskt med fokus på faser som innehåller sällsynta jordartsmetaller. Deras utvinningspotential och deras relation till liknande förekomster såsom Blötberget, Grängesberg samt Kiirunavaara har också tagits i beaktning. Bulkgeokemin i proverna analyserades med ICP-EM och ICP-MS. Polerprov av malmerna undersöktes medelst optisk mikroskopi, SEM-EDS samt med WDS-mikrosondteknik. Resultaten visar att malmerna framförallt består av magnetit och hematit, med mindre mängder silikater, flourapatit, pyrit, kopparkis, monazit-(Ce), allanit-(Ce), thoriumsilikat, titanit och zirkon. Sällsynta jordartsmetaller är i huvudsak bundna i flourapatit, men metamorfa och/eller hydrotermala processer har resulterat i nybildningen av exotiska mineral såsom monazit-(Ce), allanit-(Ce), och sekundär flourapatit. Dessa egenskaper har även observerats i apatitjärnmalmer från andra platser. Proverna från Idkerberget har 1-9 gånger högre koncentration av sällsynta jordartsmetaller än jordskorpan generellt, och lätta sällsynta jordartsmetaller är de mest anrikade. Dessa halter är relativt låga jämfört med sällsynta jordartsmalmer som bryts i dagsläget, men eftersom materialet förekommer i enorma varphögar gör tillgängligheten att metallerna ändå kan utvinnas med vinst om efterfrågan på denna resurs består.
Aiglsperger, Thomas Hans. "Mineralogy and geochemistry of the platinum group elements (PGE), rare earth elements (REE) and scandium in nickel laterites." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/396340.
Повний текст джерелаInguaggiato, Claudio. "Geochemistry of Zr, Hf and REE in extreme water environments : hyperacid, hypersaline and lake waters in hydrothermal systems." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066007/document.
Повний текст джерелаThis thesis concerns the geochemistry of Zr, Hf and REE (Rare Earth Elements) in extreme water environments. The investigations were carried out in hypersaline waters covering a wide range of Eh values along Dead Sea Fault (Israel), in hyperacid waters circulating in Nevado del Ruiz volcano-hydrothermal system (Colombia) and in CO2-rich waters in Pantelleria volcano-hydrothermal system (Italy), including the alkaline lake “Specchio di Venere” within a calderic depression. The acidic sulphates waters characterized by the precipitation of alunite and jarosite show a strong LREE depletion. The REE in waters along Dead Sea Fault show MREE enrichments in waters with relative high Ca and SO4 concentrations due to the water interaction with MREE-enriched salt minerals. In the natural waters, changing of pH and Eh induce variations of Ce and Eu anomalies, due to the different behaviour of these elements with respect to the neighbours REE. In sulphate acidic waters, Zr/Hf ratios are very low down to 4.7, while quite constant Y/Ho ratio (close to the local rock value) indicates the lack of decoupling. Zr/Hf ratio increases as Cl/SO4 ratio increases. On the contrary, Zr/Hf and Y/Ho ratios in near-neutral pH waters with positive Eh values change from near-chondritic to super-chondritic. The precipitation of Fe-oxyhydroxides removes preferentially Hf and Ho with respect to Zr and Y. The interaction of atmospheric fallout from the nearby Sahara Desert with the water of the lake “Specchio di Venere” was recognized by the Zr, Hf and REE distribution. Zr, Hf and REE show the capability to trace the interaction process between open water bodies and atmospheric fallout
Baldwin, Geoffrey James. "THE STRATIGRAPHY AND GEOCHEMISTRY OF THE RAPITAN IRON FORMATION, NORTHWEST TERRITORIES AND YUKON, CANADA." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2194.
Повний текст джерелаVanderstraeten, Aubry. "Advances in geochemical tracing of atmospheric dust in Antarctica." Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/312773.
Повний текст джерелаRésuméLes particules atmosphériques (PA) sont un composant majeur du système Terre. Leurs propriétés optiques ainsi que leur rôle au sein des processus de nucléation des nuages ont des impacts majeurs sur le budget radiatif et hydrologique de la terre. Les PA interviennent aussi dans de nombreux cycles biogéochimiques à la surface des océans ou sur terre grâce à leur capacité à fournir des nutriments clés (e.g. Fe, P) soutenant la production primaire. Le but de ce doctorat est d’améliorer la compréhension du cycle des PA en créant de nouvelles méthodes innovatrices permettant de tracer leurs origines et quantifier leurs contributions. Nous avons développé une nouvelle méthode chromatographique optimisée pour les PA afin d’analyser six systèmes isotopiques (i.e. Pb, Nd, Sr, Zn, Cu, Fe) largement utilisés pour tracer l’origine des PA. Afin de combler un manque crucial en terme de matériaux de référence (MR), nous avons quantifié deux nouveaux MR de PA, ATD et BCR-723 (représentatifs des milieux naturels et urbains) et nous les proposons pour toutes les futures études géochimiques de PA. Nous avons aussi étudié les dépositions atmosphériques le long d’un ‘transect’ de 250 km depuis la côte Antarctique jusqu’à la station Belge Princesse Elisabeth. Premièrement, nous avons réalisé des analyses morphologiques et chimiques à l’échelle de la particule à l’aide d’un Microscope Electronique à Balayage à dispersion d’énergie (MEB-EDS). Les analyses ont montré une distribution granulométrique <5 μm ainsi qu’une variation de composition chimique (i.e. minéralogie) depuis la côte jusqu’aux Sør Rondane. Deuxièmement, afin de mieux identifier l’origine de ces PA, nous avons analysé les terres rares (REE) et développé dans son intégralité une nouvelle approche statistique permettant d’identifier les sources ainsi que leurs contributions relatives. Grâce à cela, nous avons déterminé que les échantillons à la côte proviennent du Puna-Altiplano, de Patagonie et du Sud de l’Afrique (SAF). C’est la première fois que des apports du SAF sont formellement identifiés en Antarctique. Finalement, nous avons revisité les data-set de REE des carottes de glace du projet EPICA (EDC et EDML) afin de reconstruire les apports de PA durant la dernière transition glacière/interglaciaire. Nos résultats ont montré que durant la dernière période glaciaire les PA proviennent principalement de Nouvelle-Zélande (NZ) avec des apports secondaires provenant de la partie Sud du centre de l’Ouest Argentin ainsi que de Patagonie. Une transition est marquée entre 18 et 11.6 ka BP jusqu’à un équilibre dès l’Holocène (après 11.7 ka BP) marqué par des apports de sources variées venant de Patagonie, SAF, Puna-Altiplano et NZ. Nous avons aussi démontré que les variations des contributions relatives de sources enregistrées dans les carottes de glaces sont toutes en relation avec des changements climatiques importants au niveau des régions sources impactant leur capacité à générer des PA. Notre approche statistique exploitant les REE apporte une méthode sans précédent pour identifier et quantifier les sources de PA des carottes de glace d’Antarctique et ouvre de nouvelles opportunités sur ces archives du climat et de la circulation atmosphérique de la Terre.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Tourpin, Sylvie. "Perte des mémoires isotopiques (Nd, Sr, 0) et géochimiques (REE) primaires des komatiites au cours du métamorphisme : Exemple de la Finlande Orientale." Phd thesis, Université Rennes 1, 1991. http://tel.archives-ouvertes.fr/tel-00675899.
Повний текст джерелаPaquette, Jean-Louis. "Comportement des systèmes isotopiques U-Pb et Sm-Nd dans le métamorphisme éclogitique. Chaîne Hercynienne et chaîne Alpine." Phd thesis, Université Rennes 1, 1987. http://tel.archives-ouvertes.fr/tel-00675107.
Повний текст джерелаMartin, Hervé. "Nature, origine et évolution d'un segment de croûte continentale archéenne : contraintes chimiques et isotopiques. Exemple de la Finlande orientale." Phd thesis, Université Rennes 1, 1985. http://tel.archives-ouvertes.fr/tel-00655973.
Повний текст джерелаGodfrey, Linda Vivien. "Temporal changes in the geochemistry of North Pacific red clays." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359812.
Повний текст джерелаHaider, A. "Géologie de la formation ferrifère précambrienne et du complexe granulitique encaissant de Buur (Sud de la Somalie) : Implications sur l'évolution crustale du socle de Buur." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 1989. http://tel.archives-ouvertes.fr/tel-00653755.
Повний текст джерелаHardman, Tristam Samuel. "Microfabrics and geochemistry of Holcene Halimeda bank sediments, northern Great Barrier Reef, Australia." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389393.
Повний текст джерелаHibbard, Shannon Maria. "Trace Element Geochemistry of Compositionally Layered Impact Spherules." Master's thesis, Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/460665.
Повний текст джерелаM.S.
Impact spherules are sand-sized spherical particles that have been interpreted to have formed by the cooling, crystallization, and quenching of melt droplets condensed from vapor plumes that are created during large meteor impacts. Spherules may be deposited globally as unique marker beds, such as at the K-Pg boundary. A minimum of 11 spherule beds have been identified in the Archean and Paleoproterozoic, and provide a record of impact events that predate any known craters. This study of 3.24 Ga impact spherules from the S3 spherule layer in the Barberton Greenstone Belt (BGB) in the Kaapvaal Craton of South Africa focuses on the heterogeneity of textures and geochemistry produced during the cooling and crystallization of spherules within a vapor plume. Type 4b spherules are layered phyllosilicate spherules with discrete differences in texture and composition between the inner and outer layer, even after alteration. Compositionally layered phyllosilicate spherules were analyzed using Energy Dispersive X-ray Spectroscopy (EDS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to measure major, trace, and rare earth element (REE) concentrations. Backscatter Electron (BSE) images and elemental X-ray maps indicate a range of compositional differences between the inner and outer layers of type 4b spherules. The majority of REE plots have nearly flat patterns, with little to no light to heavy REE fractionation; however, the outer layers consistently have higher concentrations, averaging about 10x chondritic, whereas the interiors are at or below chondritic levels with a mid-REE enrichment. The trace and REE patterns of the type 4b spherules are consistent with a more mafic inner layer and a more intermediate outer layer. Mechanisms to produce this layered texture may include: (1) accretion of less mafic material from the plume onto existing melt droplets as the plume continues to fractionate, (2) collision of melt droplets of different viscosities, (3) by differentiation within the melt droplet prior to crystallization, or (4) by diagenetic effects. Based on textures, such as distinct boundaries between layers, and compositional patterns, such as an enrichment of Ti and REE in the outer layer, the data best fits the particle collision formation mechanism hypothesis, which has important implications for impact plume studies, such as plume density, turbulence, temperature, and opacity.
Temple University--Theses
Evans, Carol Susan. "The Geology, Geochemistry, and Alteration of Red Butte, Oregon: A Precious Metal-Bearing Paleo Hot Spring System." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3444.
Повний текст джерелаDebnath, Sudeep. "Surface/Geochemistry of Iron and Manganese Oxide Nano-Materials in the Environment." Diss., Temple University Libraries, 2009. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/30879.
Повний текст джерелаPh.D.
Nanomaterials possess physical and chemical properties that may benefit medicine, catalysis, and environmental remediation. Apart from understanding the structure of nanomaterials, significant amount of research has focused on understanding the structural properties of nanoparticles that lead to their unique reactivity. Ferric hydroxides are important mineral components and the subject of much scientific research in environmental and soil sciences because of their ubiquity in soil, ground water and aquatic sediments Iron oxide nanoparticles found in the environment exhibit size-dependent behavior. Iron oxides also play an important role in environmental chemistry. Ferrihydrite is an important iron oxide mineral as they exist in most of the sediment environment, necessary precursors for more stable iron oxides like hematite. Iron oxides are also important in many living organisms and stored as protein-encapsulated iron(III) oxyhydroxide nanoparticles. Because of the ubiquitous nature of ferrihydrite in soil and sediments, understanding correlation between the surface reactivity and the structure, phase of ferrihydrite ie. homogeneous or heterogeneous phase dependent reaction is important from environmental point of view. Iron oxides also play an important role in atmospheric chemistry and size dependent surface catalytic properties towards atmospheric gases. Green house gases are frequently generated during the burning of fossil fuels in factories and power plants, or derived from natural processes such as volcanic eruptions. Both natural and engineered metal oxides have been utilized as catalysts or sorbents for removal or minimization of green house emissions. In an attempt to understand the structure and reactivity relationship, we have presented ferrihydrite dissolution under reducing conditions and in situ kinetic studies were performed on isolated individual single particles of ferrihydrite using AFM. Bulk batch studies are also presented, where particles exist as agglomerates. Interface dissolution reaction has been characterized with FTIR and results were confirmed with theoretical calculations. Normalized dissolution rate of individual ferrihydrite particle sheds light on the phase behavior of this material. This study indicates that the ferrihydrite is uniform in composition and supports the Michel et al model. The size-dependent reactivity of ferrihydrite toward the environmentally important gas sulfur dioxide SO2 was also studied as atmospheric emission of SO2(g) affects the environment because it promotes the production of acid rain. In this investigation, nano-ferrihydrite particles were synthesized with a narrow size distribution. The surface chemistry and reactivity (SO2(g) sorption) was studied with attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy in combination with molecular orbital/density functional theory (MO/DFT) frequency calculations. Results showed that SO2(g) sorption may be a sensitive function of the structural properties and size of the nanoparticles. Like Iron oxides, Manganese oxides also play a distinctive role in superficial soil or near surface environments. Birnessite is one of the most commonly occurring manganese oxides in the soils and sediments. Birnessite are known to provide a suitable surface for heterogeneous oxidation of As(III) to As(V), and thus contribute to the environmental fate of arsenic species in soil and sediments. In the present study we have made an effort to understand this fundamental geochemistry occurring at birnessite surface at the molecular scale using advanced surface sensitive tools like AFM and spectroscopic techniques like FTIR and XPS. Nano size manganese oxide was also prepared via biological routes. Nano-size manganese oxide was prepared using ferritin protein as the biological precursor. Solution phase arsenic oxidation studies were performed with Ferritin Manganese oxide. Ion chromatography is performed to investigate oxidation of As(III) and reduction of manganese, along with XPS analysis to monitor the oxidation states of arsenic and manganese species. Results were also verified with FTIR spectroscopy for interface speciation.
Temple University--Theses
Ménot, René-Pierre. "Magmatismes paléozoiques et structuration carbonifère du Massif de Belledonne (Alpes Françaises). Contraintes nouvelles pour les schémas d'évolution de la chaîne varisque ouest-européenne." Phd thesis, Université Claude Bernard - Lyon I, 1987. http://tel.archives-ouvertes.fr/tel-00656012.
Повний текст джерелаEmmermann, Peter. "Mineralogy, geochemistry and microfacies of late Quaternary periplatform sediments carbonate export cycles and secondary processes - Sanganeb Atoll and Abington Reef, Sudan, Central Red Sea = Mineralogie, Geochemie und Mikrofazies spätquartärer Periplattformsedimente /." [S.l. : s.n.], 2000. http://e-diss.uni-kiel.de/diss%/d364.pdf.
Повний текст джерелаNarwich, Charles Bryan. "Event Stratigraphy Based on Geochemical Anomalies within a Mixed-Sediment Backbarrier Sequence, Southern New Jersey." Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/194335.
Повний текст джерелаM.S.
Detection of large-magnitude coastal events, especially in wave-dominated retrograding barrier settings, has traditionally relied upon lithological evidence, such as distinct overwash sand layers within the muddy backbarrier sequences. In tide-dominated environments, unconformities in marsh stratigraphy have been interpreted as rapid drowning or erosion events caused by large storms. In transitional mixed-energy backbarrier environments, however, clearly identifiable event horizons are rare, due to unfavorable conditions for peat formation or to a lack of overwash. To address these challenges, the present study utilized X-ray fluorescence (XRF), magnetic susceptibility (MS), and X-ray diffraction (XRD) techniques to identify anomalies within 4-to-7-m-thick sequences recovered from Sewell Point, Cape May, New Jersey. In these cores, at least five peaks were identified that exhibit up to three-to-four-fold increase in Fe (up to 6.2%) and Ti (up to 0.5%) concentrations and a substantial increase in MS values (> 200 μSI). The sand fraction at these intervals exceeds 40% and is represented by moderately well-sorted, negatively-skewed, fine-grained sand (2.7 φ). Fe, Ti, and MS are positively cross correlated due to the relatively high content of sand-sized heavy minerals such as magnetite, rutile, ilmenite and biotite, as well as phlogopite and muscovite mica. These minerals were also identified using a Rigaku Dmax/B X-ray diffraction device. Seven radiocarbon-dated in situ samples of intertidal gastropods and the few available rhizomes indicate that the Sewell Point sequence accumulated over the past 900-1,000 years, at an average sedimentation rate greater than 4.5 mm/yr, which is consistent with its proximity to a historically active tidal inlet. Lithological anomalies at Sewell Point are interpreted as the signatures of episodic large-magnitude sediment fluxes into the paleo-lagoon. The calibrated ages of organic remains (mollusks and rhizomes) constrain chronology and allow interpretation of these stratigraphic layers as event horizons with historical storms of 1594, 1743 and 1821, along with pre-historic storms in the 11th-13th centuries. This research indicates that geochemically diagnostic intervals offer an effective tool for detection of event horizons and their regional correlation in mixed-sediment backbarrier settings.
Temple University--Theses
Anné, Jennifer. "HISTOLOGICAL AND GEOCHEMICAL PROPERTIES OF PATHOLOGICAL VERSUS NORMAL BONE IN ALLOSAURUS FRAGILIS AND MODERN AVIANS." Master's thesis, Temple University Libraries, 2010. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/103924.
Повний текст джерелаM.S.
In modern organisms the structure and arrangement of bone apatite crystals is dependent on the arrangement of the organic collagen fibers. This is reflected in the formation of different types of bone tissue, such as woven (immature) or lamellar (mature), in pathological versus normal bone, or fast-growing (woven) versus slow-growing (lamellar) tissue. Because the basic physiological processes of fracture healing are similar in extant vertebrates, similar patterns may exist in fossil taxa. The three questions of interest for this study were the following: 1) Do differences exist in modern bone apatite crystallinity between normal and pathologic bone? 2) Are differences between normal and pathologic tissue consistent in both modern and fossil bone? 3) Does the type of bone tissue affect fossilization? In this study, we use histological and x-ray diffraction (XRD) analyses to examine fracture pathologies in pedal phalanges from the theropod dinosaur Allosaurus fragilis, and two modern bird species, Branta canadensis (Canada goose) and Cathartes aura (turkey vulture). Raman spectroscopy analysis was performed on modern birds, but not fossil material. Stable isotope and rare earth elements (REE) analyses were performed on fossil material to determine if there are differences in how pathologic bone fossilizes compared to normal bone. Results from Raman spectroscopy and XRD confirm that pathologic bone is more crystalline than normal bone in both fossil and modern taxa. Stable isotope and REE analyses do not show any difference in fossilization between pathologic and normal bone, suggesting that these techniques are more suitable for examining taphonomic rather than physiological differences.
Temple University--Theses
Finlay, Alyssa Jean. "Dissolution Kinetics of Bioapatite from pH 2 to 8 at 4° to 38°C." Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/182799.
Повний текст джерелаM.S.
Dissolution experiments were conducted on bioapatite at 4°C, 21°C and 38°C and solution pH values between 2 and 8 in a stirred tank reactor. The bioapatite was obtained from modern white-tailed deer (Odocoileus virginianus) scapulae, crushed, and cleaned in 30% hydrogen peroxide to remove organic matter. The average BET specific surface area of the 75-106 and 106-246 μm particles was 255 m2 g-1. During experiments the ratio of Ca:P released became stoichiometric at ca. 1.44. The following dissolution rate law was derived from the experimental results: R = K1(H+)ⁿ+K2 in which R is the dissolution rate (mol bioapatite m-2 s-1) based on the bioapatite stoichiometry, n = 1.01 ± 0.15, k1 = 1.84 x 10-6 ± 1.71 x 10-6 mol m-2 s-1, and k2 = 4.29 x 10-10 ± 1.15 x 10-10 mol m-2 s-1 and H+ is the hydrogen ion activity. From 2 < pH < 4, dissolution rate is dependent on pH and becomes independent of pH from 4 < pH < 8. These results for modern bone may be compared with previous investigations of igneous (FAP) and phosphorite-derived sedimentary carbonate fluorapatites (CFA)(e.g., Guidry and Mackenzie, 2003). At pH = 6, in the pHindependent region, dissolution of the modern bioapatite was ca. 7 times faster than FAP and 100 times faster than CFA. The acid transition pH of the bioapatite (pH = 4) is lower than that for FAP (pH = 6). Bioapatite dissolution rates influence fossil preservation potential, the release rate of nutrients from bone meal fertilizers, the effectiveness of bone as reactive barriers to control pollutants and nuclear waste isolation, and as a feedstock material in CO2 sequestration processes.
Temple University--Theses
Klein, Trevor Isaac. "Investigating nitrate attenuation in an urban stream using stable isotope geochemistry and continuous monitoring." Master's thesis, Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/319212.
Повний текст джерелаM.S.
Urbanization affects in-stream biogeochemical processes that control nutrient export. Attempts to restore urban streams will not be successful unless the biological and physical controls on water quality are thoroughly understood. The objective of this study was to identify the relative influences of tributary dilution, groundwater discharge, and biological processing on nitrate concentrations in an urban stream during high and low flow periods. A wastewater treatment plant (WTP) on Pennypack Creek, an urban stream near Philadelphia, PA, increases nitrate concentrations to a mean of 8.5 mg-l-1 (as N). Concentrations decrease to 5.5 mg-l-1 about 7.5 km downstream. Reaches along this distance were sampled for nitrate concentration and delta-15N at fine spatial intervals to determine the reasons for this decrease. To quantify the effects of dilution, samples were collected from tributaries, groundwater springs, and upstream and downstream of tributaries or groundwater discharge zones identified through terrain analysis and continuous temperature modeling. These methods were also used to identify and sample reaches along which hyporheic flow occurred, where nitrate biological processing is often concentrated. In addition, loggers were installed at closely spaced sites to monitor daily fluctuations in nitrate, dissolved oxygen, and related parameters, which provided further indications of biological processing. Longitudinal sampling revealed decreases in nitrate concentration of 2 and 6.5 mg-l-1 during high and low flow, respectively. During high flow, delta-15N varied from 9.5 to 10.5 per mille downstream of the WTP, while delta-15N varied from 10.14 to 11.06 per mille throughout this reach during low flow. Mixing analysis indicated that groundwater discharge and biological processing both control nitrate concentration during both flow periods. Larger declines in nitrate concentration were observed during low flow than during high flow, and delta-15N fell between biological and groundwater signatures, indicating that both processes were enhanced. Continuous nitrate concentrations displayed distinct diurnal cycles often out-of-phase with dissolved oxygen cycles, indicating autotrophic processing. However, shifts occurred in nitrate cycle timing at a weekly scale wherein daily maximum concentrations were observed as many as 6 hours closer to noon than previously. These shifts were comparable to shifts observed across seasons in other studies, and by the end of the summer, nitrate and dissolved oxygen cycles were in-phase. Furthermore, shifts in nitrate cycles could not be linked to shifts in daily fluctuations of WTP discharge. Longitudinal sampling and continuous monitoring suggest that biological processing is an important control on nitrate concentrations in urban systems, though documenting its signature may be complicated by groundwater discharge and anthropogenic inputs.
Temple University--Theses
Gangloff, Sophie. "Evaluation of the mechanisms of trace elements transport (Pb, Rare Earth Elements,... ) and the elemental and isotopic fractionation (Ca and Sr) at the interface water-soil-plant." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAH002/document.
Повний текст джерелаThis work is focused on the study of a profile of soil and soil solutions collected on an experimental plot covered with spruce. All these samples come from the watershed of the Strengbach (environment - OHGE Hydrogeochimique Observatory), were sampled at different depths (5, 10, 30 and 60 cm) and during the period between 2009 and 2013. Characterizations of soil extracts by infrared spectroscopy allowed to highlight changes in the organic functional groups with depth and that these changes have a significant impact on the behaviour of the cations (major and trace) in the soil. Ultrafiltration experiments helped to identify flows of colloidal and dissolved organic carbon as well as those of the major and trace-element present in soil solutions. The joint use of isotope tracers (87Sr / 86Sr and δ44 / 40 Ca) and chemical (Rare Earth Elements) have highlighted processes taking place at the water-soil-plant interface, as the uptake by root or soil alteration
Peterson, Stephen Patrick. "THE GEOLOGIC, GEOMORPHIC, AND GEOGRAPHIC INFLUENCE ON LEAD AND OTHER HEAVY METAL CONCENTRATIONS IN THE SOILS OF FAIRMOUNT PARK, PHILADELPHIA." Master's thesis, Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/270852.
Повний текст джерелаM.S.
The city of Philadelphia is an amalgamation of extremely diverse land uses, both currently and historically, including: transportation, industrial, commercial, parks and residential areas. This urban tapestry of historical and current land use creates the potential for human exposure to heavy metals in contaminated soils. In order to evaluate this potential public health hazard, soil samples from open spaces in Philadelphia's Fairmount Park (the largest inner-city park system in the U.S.) were analyzed using a handheld x-ray fluorescence (XRF) analyzer and inductively coupled plasma-mass spectrometry (ICP-MS), focusing on Lead (Pb). Three distinct types of land use were identified for detailed analysis: undisturbed parkland, recently disturbed parkland and urbanized park/recreational land. At each location bulk and core samples were taken at specific geomorphic positions along a toposequence or, if little to no topographic change was present, samples were collected at specific intervals from structures or roads. These sites were compared to the geologic background Pb concentration (33 ppm). Less than 1% of samples analyzed were at or below the background Pb concentration for the region, suggesting anthropogenic input of Pb into the system. In total, 24 sites were sampled with three sites chosen for additional core and sequential extraction analysis. Selected samples were sequentially digested to determine Pb fractionation via ICP-MS. In most samples the Pb distribution was: Fe/Mn oxides > residuals > organic > carbonate > exchangeable fraction. Thus, most Pb was in less biologically available fractions. From the total Pb concentration data comparisons were made to a previously published model explaining Pb distributions in the urban environment, incorporating buildings to act as a baffle for aerosolized Pb particles, thus leading to increased Pb concentrations at the base of structures. By modifying this model and using a hill slope as the baffle, these data indicate that geomorphology can concentrate Pb at the bottom of hill slopes in a similar manner. Using the data collected in this study, we can develop an improved sampling model to characterize the potential public health risk associated with these three types of land use in Fairmount Park. This same approach can be used on public lands throughout the Philadelphia region in order to better assess the potential public health hazard posed by Pb and other toxic metals.
Temple University--Theses
Mahizhnan, Annamalai. "Red-brown hardpan: distribution, origin and exploration implications for gold in the Yilgarn Craton of Western Australia." Thesis, Curtin University, 2004. http://hdl.handle.net/20.500.11937/1732.
Повний текст джерелаMurphy, Riley Tomas. "Reactivity of Iron-Bearing Minerals Under Carbon Sequestration Conditions." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/140596.
Повний текст джерелаPh.D.
The rise in anthropogenic carbon dioxide in the atmosphere has caused the pursuit of adequate methods to alleviate the resulting strain on the world's ecosystem. A promising strategy is the geological sequestration of carbon dioxide, in which carbon dioxide emitted from large point sources is injected underground for storage. Under storage, carbon dioxide trapped as a carbonate mineral may be stable for geological time periods. Experiments were conducted to test the potential of ferric-bearing minerals to sequester carbon as a ferrous carbonate mineral (siderite). The formation of siderite requires the reduction of ferric ions which may be achieved by the co-injection of H2S or SO2 contaminants with CO2. Both ferrihydrite and hematite nanoparticles were exposed to an aqueous Na2S solution in the presence of supercritical CO2 (scCO2) and were analyzed in situ by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). In situ ATR-FTIR indicated that the formation of siderite occurred on the order of minutes for ferrihydrite and hematite nanoparticles. Particles were analyzed post-reaction with X-ray diffraction (XRD) and electron microscopy. XRD results indicated that ferrihydrite reacted completely to form siderite and elemental sulfur after 24 h at 100 °C, while hematite only partially reacted to form siderite and pyrite after 24 h at 70 °C. Additionally, hematite nanoparticles were exposed to H2S and scCO2 in a series of batch reactions, and the reaction products were determined by XRD as a function of CO2 and H2S partial pressures, alkalinity, salinity, time, and temperature.
Temple University--Theses
Banuchi, Victoria B. Beatriz. "Ultraviolet Photooxidation and O2 Chemical Oxidation of Fe2+ -Smectites and Implications for Mars." Master's thesis, Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/520832.
Повний текст джерелаM.S.
Clay minerals detected in ancient Martian terrains help constrain Mars’ climate and aqueous alteration history. Since Mars’ primordial origin, atmospheric redox conditions have evolved from reducing to oxidizing and clay minerals may record the effects of that transition. Ferrous trioctahedral smectites of varying iron content were synthesized and subjected to oxidation by O2 and by UV irradiation to address these as potential oxidizing agents. UV irradiation (112.77 hours with 450 W Hg lamp) of smectites equivalent to approximately four years of flux on the Martian surface caused incomplete oxidation (Fe3+/ΣFe = 16-18%). O2 experiments (two hour, twelve hour, two day, and five day) produced more oxidation in smectites with higher Fe content at the same exposure times. Photooxidation caused octahedral sheet contraction; however, chemical oxidation allowed more contraction to occur in the high Fe smectites. The mid and high Fe smectites had observable changes in their visible-near infrared (VNIR) reflectance spectra with the formation of a nontronite (Fe3+, Mg)2-OH feature at 2.3 µm, even with partial oxidation. With both oxidation experiments, the reflectance spectra lost its initial MMM-OH features (AlAl(Fe2+,Mg) and Fe2+MgMg-OH) and produced a single nontronite-like MM-OH feature. UV irradiation produced a secondary nontronite phase, possibly on the surface of the higher Fe content smectites; however there was no evidence for iron ejection. Ferrous smectites are capable of undergoing UV photooxidation under aqueous conditions and this process could have occurred during early Martian history. Distinguishing between UV and O2 oxidation in smectites cannot be completed exclusively with Martian spectra; however, the lack of secondary oxides may hint at alteration history based on the nature of mineral assemblages detected on Mars.
Temple University--Theses
Moore, Nicole E. DeBari Susan M. "Origin and geochemical evolution of mafic magmas from Mount Baker in the northern Cascade arc, Washington : probes into mantle and crustal processes /." Online version, 2010. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=345&CISOBOX=1&REC=14.
Повний текст джерелаMyer, Caroline Amelia. "Sedimentology, Stratigraphy, and Organic Geochemistry of the Red Pine Shale, Uinta Mountains, Utah: A Prograding Deltaic System in a Mid-Neoproterozoic Interior Seaway." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/167.
Повний текст джерелаWestfield, Isaac T. Dworkin Steve I. "Geochemical fingerprinting of sediments on the Pear Tree Bottom Reef, near Runaway Bay, Jamaica." Waco, Tex. : Baylor University, 2008. http://hdl.handle.net/2104/5289.
Повний текст джерелаMahizhnan, Annamalai. "Red-brown hardpan: distribution, origin and exploration implications for gold in the Yilgarn Craton of Western Australia." Curtin University of Technology, Department of Applied Geology, 2004. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15888.
Повний текст джерелаIn present-day higher rainfall (400 to 500 mm) regions, red-brown hardpan is being weathered. There is no relationship between the distribution of mulga (Acacia aneura) and red-brown hardpan. Red-brown hardpan is exclusively developed in colluvium containing a minimum of 20% quartz, 15% clays and 2% iron oxides. It is bright reddish brown to reddish brown, earthy, with a sandy loam texture, blocky structure and porous. Red-brown hardpan is hard (up to 12 MPa), being characterised by sub-horizontal laminations predominantly of uncemented kaolinite. Ped surfaces may be coated by Mn oxide and carbonate which may be precipitated along the laminations. The mineralogy of the cement is complex. Data from XRD, SEM, TEM, EFTEM, FTIR and NIR investigations show poorly-ordered kaolinite and opal-A as the main components. Illuvial multilayered argillaceous cutans containing silica and alumina in a ratio of 2:l form the cement. Secondary silica (SiO2-95%) coatings are common, mainly as opal-A, on ped surfaces and on the inner walls of voids and vughs. Etch pits are developed in these coatings and some of them are filled by kaolinitic clays. Selective dissolution experiments using acid ammonium oxalate show that oxalate- soluble amorphous and poorly ordered silica and alumina in red-brown hardpan have molar ratios of about 1.6 to 2 A1203:SiO2.
These results suggest that red-brown hardpans were formed where there was sufficient water during the wet season to dissolve alumina and silica, but insufficient to leach them. During the subsequent dry season, the dissolved alumina and silica was precipitated as poorly-ordered kaolinite and opal-A. Successive dissolution and precipitation led to fusion of poorly-ordered kaolinite and opal-A at a nanometre scale to progressively cement the colluvium. The age of the red-brown hardpans, estimated by paleomagnetic dating of hematite, is from Pleistocene to present. Based on the findings of this research, the red-brown hardpan is redefined and primarily classified on its degree of cementation as: (1) weakly cemented, (2) moderately cemented and (3) strongly cemented. It is further classified chemically into: (1) siliceous, (2) calcareous and (3) ferruginous. In the Yilgarn Craton, red-brown hardpan is believed to occur mainly north of the 'Menzies Line'. However, this study reveals the presence of red-brown hardpan 75- 150 km south of the Menzies Line and the new southern boundary is closer to latitude 29ºs. Geochemical investigation at the Federal Open Pit Gold mines, Broad Arrow, north of Kalgoorlie indicate that there are Au anomalies in red-brown hardpan. Gold concentration is up to 50 ppb against the background anomaly of 10 ppb. Sequential and partial extraction analyses show significant correlation of Au with Ag, Ca, Ce, Co, Mg, Mn and Ni. This suggests that the Au concentration in red-brown hardpan is due to: (a) mechanical dispersion due to reworking of Au-bearing clasts in the sediment and (b) hydromorphic dispersion from the underlying mineralisation. It can therefore be used as a useful sampling medium for gold exploration.
Cerkez, Elizabeth B. "Investigations of Surface Redox Chemistry on Environmentally Relevant Iron Oxides and Sulfides." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/383744.
Повний текст джерелаPh.D.
Important reactions in the environment often occur at the interface between a mineral surface and aqueous phase. Reactions occurring at this interface often control the uptake or release of harmful components resulting in the geochemical cycling of elements in the environment. Additionally, minerals are commonly used in the remediation of contaminated areas, where similar chemistry occurs at their interfaces. Thus, studies of the chemistry of these interfaces are essential to our understanding of complex environments. Many of these processes are controlled by electron transfer reactions between adsorbates and the mineral interface, and it is here where this research presented will concentrate. The studies in this thesis key in on redox chemistry on various environmentally relevant iron minerals, including ferrihydrite, pyrite, and amorphous iron sulfide. A large portion of this body of work is dedicated to the understanding of the surface mediated reaction between chromate (Cr(VI)) and arsenite (As(III)). Both of these species are present in the environment and are detrimental to human health. Using in- and ex-situ experiments we have monitored the coupled redox transformation of Cr(VI) and As(III) to chromite (Cr(III)) and arsenate (As(V)). Quantum mechanical modeling was used to support the experimental studies of this novel redox chemistry. The reaction was monitored in situ, using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), on the surface of the iron oxyhydroxide, ferrihydrite, at various solution pH values by following vibrational modes unique to Cr(VI), As(III), and As(V). At pH < 9 we observed an initial growth of Cr(VI) vibrational modes due to adsorption, followed by the simultaneous decrease in Cr(VI) vibrational modes and increase in As(V) vibrational modes. Ex situ analysis of the reaction products via X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) indicated that there was an increase in the percentage of reaction products as the pH decreased. Quantum mechanical calculations were completed to model the reaction of Cr(VI) and As(III) on the ferrihydrite surface by analyzing differences in geometric and electronic structural changes and thermodynamic preferences. The results indicate that Cr(VI) and As(III) adsorbed physically separated from each other is not only thermodynamically favorable but results in changes in As(III)-Fe and Cr(VI)-Fe atomic distances, towards those characteristic of As(V)-Fe and Cr(III)-Fe. Thus a mechanism where electron transport occurs through bulk states is plausible. Additionally, natural bond order analysis reveals a redistribution of electron density away from the Cr(VI) atomic center upon adsorption, indicating probable changes in Cr(VI) reduction potential. The electrochemical reduction of Cr(VI) on three surfaces, ferrihydrite, titanium dioxide, and aluminum oxides, indicate that Cr(VI) reduction potential is surface dependent, an observation that has significance for redox chemistry in the environment. The interaction of ferric, Fe(III), with iron sulfide surfaces (during and after coal mining activities) contributes to the detrimental environmental problem known as acid mine drainage (AMD). We investigated whether Fe(III) chelating siderophores could be used to suppress the oxidation of iron sulfide surfaces and the resulting AMD chemistry. The exposure of the iron sulfide, pyrite, to the siderophore, desferrioxamine B (DFOB) at initial pH values of 3, 6, and 8 under oxic conditions showed a significant decrease in the rate of dissolution of pyrite: decreases of 43.7%, 37.5% and 78.4%, respectively. An even greater decrease in pyrite oxidation was observed when DFOB was present in anoxic conditions, specifically 56.1%, 74.4% and 91.5%, at pH 3, 6 and 8, respectively. We further compared the rate of dissolution between DFOB and another siderophore, enterobactin, which is a stronger chelator of Fe(III). The presence of enterobactin suppressed pyrite oxidation more than DFOB, consistent with the contention that inhibiting the interaction of Fe(III) with pyrite will decrease the oxidation of the mineral. We also analyzed the exposure of the pyrite surface to DFOB using ATR-FTIR, to determine if any surface chelation occurs. We found that when Fe(III) is present on the pyrite surface, DFOB adsorbs to the surface via hydroxamate groups, similar to the aqueous phase spectra of DFOB-Fe(III) complex. In contrast the spectra do not exhibit hydroxamate vibrational modes when Fe(III) was not initially present on the pyrite surface and in this circumstance the spectra resembled that of aqueous phase unchelated DFOB. Taken together the results showed that siderophore inhibited pyrite oxidation by chelating Fe(III) present on the pyrite surface and in solution. Finally, the reduction of NO(g) to NH3/NH4+ with amorphous iron sulfide (FeS) was studied. The exposure of NO gas to a suspension of FeS solid resulted in the conversion of 2.3% NO(g) to the reaction product ammonia (NH3), which was found to grow over time, while the exposure of NO(g) to water (in the absence of mineral) resulted in no NH3 formation. Additionally, we completed in situ analysis of NO exposure to FeS as a function of water concentration using ATR-FTIR. The exposure of NO to an aqueous paste of FeS or a FeS film (with adsorbed H2O), resulted in the adsorption of NO to the FeS surface and the subsequent production of NH3, as indicated by N-H vibrational modes. In contrast, the removal of all water, via thermal desorption from the film, resulted in the adsorption of NO but did not show vibrational modes consistent with the formation of NH3. We conclude that the presence of H2O, as a source of protons, and a FeS surface, as a source of electrons, results in the transformation of NO to NH3 via a heterogeneous reaction. This result has important implications towards remediation of NOx gases and mechanisms of prebiotic synthesis of NH3. In summary, the research presented expands our understanding of redox reactions at mineral interfaces in the environment. The work herein aims to inform and aid in the development of remediation methods for arsenic and chromium, the formulation of methods to inhibit the production of acid mine drainage, and develop our understanding of toxic NOx gas reduction on surfaces.
Temple University--Theses
Hausner, Douglas B. "Surface Science Investigations: Calcite Surface Reconstruction and Ferrihydrite Reactivity." Diss., Temple University Libraries, 2009. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/44342.
Повний текст джерелаPh.D.
On surfaces and within interfaces occur some of the most important reactions in chemistry, from world changing industrial reactions to critical environmental processes. It is even hypothesized that the chiral nature of life arose from reactions occurring on chiral mineral surfaces. In any case adsorption typically plays a key role. Adsorption can occur on rapid time scales, particularly in catalytic systems, and it can be the precursor to highly stable surface interaction mechanisms such as surface precipitation. Surface adsorption can have a dramatic affect on the resulting surface increasing or decreasing the propensity for further reactivity or adsorption. In order to understand the processes occurring on a surface both the surface and the adsorbate must be understood. This includes a surface with any prior adsorbates. This is why many catalytic studies are done in UHV environments where clean surfaces are prepared for each experiment. The same is true with environmental surfaces, but obtaining pristine surfaces can be problematic, and systems are often extremely complicated involving organic, inorganic, and biological components. Often research is focused on just one component. A significant portion of this dissertation is focused on the adsorption of organic and inorganic species on pristine mineral surfaces. While there is significant research done on environmental surfaces, often times the surface used in studies is not well characterized. In essence lesser attention is paid to the substrate then the adsorbate. This is particularly true of infrared studies similar to the type presented in chapter 5 where carbonate is shown to exist in significant quantity on all ferrihydrite surfaces. Furthermore, chapter 4 highlights the potential for ion mobility on calcite surfaces under ambient conditions and the effect the adsorbates in chapter 3 have on the mobility process. The principal of this dissertation is to characterize fundamental surface processes which occur on calcite and ferrihydrite surfaces under ambient conditions. The hope is that this can lay the ground work for future studies where native adsorption and restructuring is taken into account on mineral surfaces during experimental studies.
Temple University--Theses
Paulson, Benjamin D. DeBari Susan M. "Magmatic processes in the Jurassic Bonanza arc : insights from the Alberni region of Vancouver Island, Canada /." Online version, 2010. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=331&CISOBOX=1&REC=3.
Повний текст джерелаLammers, 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.
Повний текст джерелаPh.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
CHAKRABORTY, SUVANKAR. "THE GEOCHEMICAL EVOLUTION OF ALKALINE MAGMAS FROM THE CRARY MOUNTAINS, MARIE BYRD LAND, ANTARCTICA." Bowling Green State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1174187928.
Повний текст джерелаPalin, Richard Mark. "Using metamorphic modelling techniques to investigate the thermal and structural evolution of the Himalayan-Karakoram-Tibetan orogen." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:f86580ad-c183-4ecd-bcbd-17f3a1b74548.
Повний текст джерелаBerglund, James Lundstrom. "Karst Aquifer Recharge and Conduit Flow Dynamics From High-Resolution Monitoring and Transport Modeling in Central Pennsylvania Springs." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/589966.
Повний текст джерелаPh.D.
Karst aquifers are dynamic hydrologic systems which are sensitive to short-term recharge events (storms) and heterogeneous recharge characteristics (point recharge at sinks, irregular soil thicknesses). These aquifers are highly productive yet also vulnerable to contamination, in large part because the conduit network is a significant unknown for predicting karst flow paths. To address these uncertainties, two adjacent karst springs, Tippery Spring and Near Tippery Spring, were monitored to better understand flow and source mixing characteristics. The two springs in central Pennsylvania’s Nittany Valley have similar discharges and are only 65 meters apart, yet they show unique behaviors in terms of water chemistry and discharge response to storms. First examined for flow characterization in 1971 by Shuster and White, the springs were analyzed in this study using high-resolution logging and new tracers such as rare earth element (REEs) and Ca/Zr ratios. This research contributes to the field of karst hydrology through innovative water sampling and monitoring techniques to investigate karst recharge and flow behavior along with conduit flow models incorporating multiple calibration target datasets such as water temperature and dye tracing. Stable isotope signatures (δD & δ18O) of storm water samples at the two springs varied based on storm intensity, but also due to their unique recharge behaviors. Increased spring discharge preceded the arrival of storm water as conduits were purged of pre-storm water, indicated by no change in isotopic composition on the rising limb. The isotopic signature then became progressively more enriched at both springs, indicating storm water recharge. At Tippery, this enrichment began around peak flow, sooner than at Near Tippery where enrichment began during the descending limb. Thus, isotopes indicated a stronger surface connection at Tippery Spring. Storm intensity also affected the relative contribution of recharging water reaching both springs, with a larger storm producing a larger recharge signature compared to a smaller storm. At Tippery Spring, for a short time the majority of emerging water was storm water, which may indicate a reversal in water exchange between the conduits and the surrounding matrix, an important consideration in karst contaminant transport. Two natural tracers were applied in new ways for this study: Ca/Zr ratios and REE patterns. Both tracers provided additional information about flow paths and recharge sources as they varied during the storm hydrograph. Ca/Zr ratios changed in timing and intensity with storm intensity, and both springs exhibited a decline in Ca/Zr ratios as calcium-rich carbonate matrix water was displaced by zirconium-rich storm recharge water from sinking streams off the clastic upland ridges. Being a storm water arrival indicator in clastic-ridge-fed Valley and Ridge springs, this relationship made Ca/Zr ratios a useful substitute for stable water isotopes while also providing information on source area. In response to storm water recharge, REE concentrations increased with the arrival of storm water. The timing and magnitude of concentration increases were influenced both by the degree of surface connectivity intrinsic to each spring and the intensity of the recharge event. Elevated REE concentrations persisted after other parameters recovered to pre-storm levels, suggesting water which has interacted with either the local carbonate matrix or the upland siliciclastics. These slower flow paths recharging the two springs were not apparent from other geochemical parameters. This study illustrated the relationships among multiple tracers to understand source waters in different periods of storm hydrographs. A flow and transport model using the Finite Element Subsurface Flow Model (FEFLOW) was calibrated using quantitative dye trace and high resolution temperature data to simulate the connection between a sinking stream and Tippery Spring. Dye was injected at the sink and monitored at the spring while temperature data was collected using loggers at both the sink and the spring. FEFLOW was used to simulate the connection between sink and spring through varying conduit geometries, sink and spring discharges, conduit conductivity, conduit cross-sectional area, matrix transmissivity, matrix porosity, and dispersivity. Single conduit models reproduced larger peak and recession concentrations than observed. A forked conduit model diverted flow from the main conduit, reducing the concentration of dye reaching the spring, provided a better match. Latin Hypercube sensitivity analysis indicated that dye concentration breakthrough curves were most sensitive to conduit conductivity and less sensitive to other model parameters. Temperature data from high-resolution loggers at the sink and spring were then incorporated into the model scenarios to reproduce seasonal spring temperature using the conduit configuration fit to the dye trace. Simulated temperature signals at the spring were sensitive to parameters in addition to conduit conductivity, most notably matrix transmissivity and inflow rates at the sink. The dual approach to karst model calibration using a temperature model set up from an initial dye trace results in greater model confidence due to a limited possible range in conduit conductivity. This study improved conceptual and numerical models for karst by examining how data from storm events and tracers can be used to better understand recharge and flow paths.
Temple University--Theses
Silva, Renata Maria Goulart da. "Acúmulo de metais-traço no sedimento e em organismos da megafauna bentônica na Baía do Almirantado, Ilha Rei George, Antártica." Niterói, 2017. https://app.uff.br/riuff/handle/1/4783.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
Nos últimos anos observa-se um aumento crescente das atividades humanas, tanto científicas quanto turísticas, no ambiente antártico, sendo motivo de preocupação considerando-se que a Antártica é um ambiente de lenta recuperação. Ainda são escassos os estudos sobre o estabelecimento de relações entre a presença de contaminantes e seus efeitos na biota antártica. A contaminação pode ocorrer por processos antrópicos ou naturais e os efeitos destes impactos podem ser detectados e monitorados através da análise das alterações nas comunidades bentônicas. Estas comunidades podem ser consideradas boas indicadoras de impactos ambientais, já que possuem uma relação direta com a origem dos contaminantes acumulados nos sedimentos. Este trabalho avaliou os níveis de metais-traço encontrados no sedimento e em duas espécies circumpolares da megafauna bentônica antártica, a estrela-domar Odontaster validus e o molusco bivalve Laternula elliptica, com a finalidade de determinar se as mesmas podem ser utilizadas como indicadoras de impacto ambiental. Durante o verão austral de 2005/2006 foram realizadas coletas através de diferentes procedimentos, entre 15 e 40m de profundidade, em cinco estações dentro da Área Antártica Especialmente Gerenciada da Baía do Almirantado, Ilha Rei George: 1) Estação Antártica Comandante Ferraz; 2) Botany Point; 3) Punta Ullman; 4) Punta Plaza e 5) Refúgio II. Os seguintes metais foram quantificados tanto para o sedimento quanto para os organismos: Al, V, Cr, Mn, Fe, Ni, Cu, Cd, Ba, Pb e Zn. A concentração de metais variou entre os diferentes compartimentos corpóreos analisados. Para a espécie O. validus, as maiores concentrações de metais-traço (Mn, Ni, Cd, Ba, Pb) e do macronutriente Al, foram encontradas na parede do corpo. Cu, Cr, V e Zn apresentaram maior concentração no estômago, enquanto o macronutriente Fe concentrou-se preferencialmente nos cecos pilóricos. Para a espécie L. elliptica, as maiores concentrações de metais-traço (Mn, V, Ba, Cu) e dos macronutrientes Fe e Al, foram encontradas no sifão. Cd, Ni, Pb e Zn apresentaram maior concentração no rim enquanto o Cr foi mais concentrado no compartimento restos. A concentração de elementostraço nos compartimentos corpóreos de O. validus e L. elliptica não foi influenciada pelo tamanho do organismo (peso total do indivíduo).
Once the Antarctic environment has low recovery rates, the recent growth in the touristic and scientific activities is a serious issue for the scientific community. Few studies have tried to establish the links between the presence of contaminants and the antarctic biota. The contamination may be related to human or natural processes, and be monitored trough the benthic communities. These communities have a direct relation with the contaminants sources in the sediment. The present work analyzed the trace-metals levels found in the sediment and two circumpolar benthic megafauna species in Antarctica, the starfish Odontaster validus and the Antarctic clam Laternula elliptica. The objective was to establish if these species can be used as environmental indicators. Five stations was occupied during the austral summer of 2005/2006, between 15 and 40m deep, in the Antarctic Special Management Area of Admiralty Bay, George King Island: 1) Comandante Ferraz Antarctic Base; 2) Botany Point; 3) Punta Ullman; 4) Punta Plaza and 5) Refúgio II. Analyzes were conducted to quantify the presence of Al, V, Cr, Mn, Fe, Ni, Cu, Cd, Ba, Pb and Zn, both in the sediment and organisms. The metals concentrations vary in the different body compartments. Larger concentrations of (Mn, Ni, Cd, Ba, Pb) trace metals and Al macronutrient were found in the body walls of O. validus. Cu, Cr, V and Zn showed larger concentrations in the stomach and the Fe macronutrient in the caeca pyloric. For L. elliptica, larger trace metals (Mn, V, Ba, Cu) and macronutrients (Fe and Al) concentrations were found in the sifon, while Cd, Ni, Pb and Zn showed larger concentrations in the kidney. Cr presented larger concentrations in the remains compartment. The concentrations of trace elements in both O. validus and L. elliptica were not influenced by the body size (total individual weight).
Laubscher, Sydney. "MANGANESE UPTAKE IN RED MAPLE TREES IN RESPONSE TO MINERAL DISSOLUTION RATES IN SOIL." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1574431912056187.
Повний текст джерелаBostock, Helen C., and Helen Bostock@anu edu au. "Geochemically tracing the intermediate and surface waters in the Tasman Sea, southwest Pacific." The Australian National University. Faculty of Science, 2005. http://thesis.anu.edu.au./public/adt-ANU20061106.123254.
Повний текст джерелаZheng, Xinyuan. "Oceanic cycling of rare earth elements and the application of Nd isotopes to assess changes in Mesozoic ocean circulation." Thesis, University of Oxford, 2016. http://ora.ox.ac.uk/objects/uuid:0b06129a-8f51-4421-a043-5eeb86cec972.
Повний текст джерелаBellefleur, Alexandre. "Cinétique de réaction et solubilité des produits de corrosion dans les conditions physico-chimiques du circuit primaire des réacteurs à eau sous pression (REP)." Phd thesis, Université Paul Sabatier - Toulouse III, 2012. http://tel.archives-ouvertes.fr/tel-00767055.
Повний текст джерелаStepanov, Aleksandr S. "Monazite control on Th, U and REE redistribution during partial melting: experiment and application to the deeply subducted crust." Phd thesis, 2012. http://hdl.handle.net/1885/9432.
Повний текст джерелаGeer, Phillip. "Magnetite Mineralization of the Hammondville Pluton: Poly-Phase Kiruna Type IOCG Magnetite-Apatite Deposits in the Lyon Mountain Granite." 2020. https://scholarworks.umass.edu/masters_theses_2/965.
Повний текст джерелаTrestrail, J. L. "U-Pb detrital zircon, geochemical and Nd isotope constraints on sedimentary provenance of the Chewings Range Quartzite, Warumpi Province, Arunta Region, NT." Thesis, 2010. http://hdl.handle.net/2440/106279.
Повний текст джерелаThe Chewings Range Quartzite is a meta-sedimentary cover sequence located in the Warumpi Province of the Arunta Region. U-Pb detrital Zircon analysis of the Chewings Range Quartzite indicates a minimum depositional age of ~ 1640Ma, with the main population of zircons residing within a range of 1700 – 1800Ma. Evidence from Sm-Nd isotopic data suggests that a series of Staurolite Garnet Schists, often grouped with the Chewings Range Quartzite, has a significantly more juvenile character. This suggests that it may represent a new unit with a significantly differing provenance to that of the Chewings Range Quartzite. Combined REE, geochemistry and detrital zircon dating suggests that the Chewings Range Quartzite was derived primarily off the Arunta Region and North Australian Craton, while the Stauralite Garnet Schists holds more affinity with juvenile Musgrave Province to the south.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Повний текст джерелаRasmussen, Stephen Eric. "Neutron activation analysis of samples from the Kimberley Reef Conglomerate." Thesis, 2015. http://hdl.handle.net/10539/18147.
Повний текст джерелаGallagher, Shaun. "Geology, Geochemistry and Geochronology of the East Bay Gold Trend, Red Lake, Ontario, Canada." 2013. http://hdl.handle.net/1993/18726.
Повний текст джерелаBrown, Raylan Talbot. "The petrology and geochemistry of the Merensky reef in the Rustenburg area." Thesis, 1994. http://hdl.handle.net/10413/4948.
Повний текст джерелаThesis (M.Sc.)-University of Natal, Pietermaritzburg, 1994.