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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

A lithogeochemical study of northern Sweden and the Kiruna and Malmberget iron-apatite ore deposits

Lundh, Jon January 2014 (has links)
The iron apatite mineralizations of northern Sweden are mainly situated in supracrustal rocks and are thought to have formed during approximately the same time as the major plutonic suites in northern Sweden. In this thesis the Malmberget iron apatite ore deposit have been compared to the Kiruna iron apatite ore deposit to see whether the role of hydrothermal processes are different between the two ore districts. Also, since it has proven problematic to distinguish between the different mafic and ultramafic members of the major plutonic suites in northern Sweden (i.e. the Haparanda suite (1.94-1.85 Ga), the Perthite-monzonite suite (PMS) (1.87 Ga) and the Edefors suite (1.80-1.79 Ga)), a second goal is to trace the distribution and distinguish between these suites. Major elements, REE and trace elements have been studied along with polished sections from the ores and oxygen isotopes of magnetites from the ore districts to trace the ore formation process and separate between suites. All ore districts display a close similarity in geochemistry between host rocks and magnetites, especially regarding the REE pattern. Oxygen isotopes show that samples from the Kiruna district plot exclusively at positive δ18O-values with the majority of them at values < 1‰. Samples from the Malmberget district display δ18O-values either close to the igenous range or at slightly negative values. However, samples that display very low or negative δ18O-values show signs of either high temperature hydrothermal alteration, oxidation or crustal contamination. The δ18O composition along with textural observations from the polished sections and geochemistry, points towards a magmatic origin for these deposits. No apparent evidence has been found to support a primary ore formation by hydrothermal process in any of the districts studied. Regarding the suites, normalized spider plot patterns of REEs and trace elements served as a basis for subdivision into groups by similarities in key identification parameters. Several patterns are characterized by a pronounced Eu-trough while the middle- to HREEs display a rather flat trend, criteria that are related to rocks from the Haparanda suite, while samples with positive Eu-anomaly (Eu/Eu* > 1) and a nearly flat trend from La to Pr with a marked positive peak at Sr and generally less enriched in LILE, are consistent with the Edefors suite. Also, the Edefors suite generally display low concentrations of both Th and U but are somewhat enriched in Sr with relation to Pr. No distinct geochemical features could help to separate between the Haparanda and the PMS suites.
392

Variations inter- et intra-spécifiques de la phytoextraction des éléments traces As, Cd, Cu, Ni, Pb et Zn chez trois cultivars de saule

Constantineau, Simon 11 1900 (has links)
La phytoextraction représente une solution environnementale prometteuse face au problème de contamination des sols en éléments traces (É.T). La présente étude s’intéresse aux différences intra et interspécifiques (S. purpurea, S. dasyclados, S. miyabeana) de trois cultivars de saule lorsqu’ils sont utilisés pour la phytoextration de six É.T. (As, Cd, Cu, Ni, Pb et Zn). Les objectifs sont (i) décrire les variations intrapécifiques du cultivar FISH CREEK (S. purpurea) lorsqu’il est utilisé pour la phytoextraction sur deux sites d’étude; et (ii) décrire les variations intra et interspécifiques des cultivars FISH CREEK (S. purpurea), SV1 (S. dasyclados) et SX67 (S. miyabeana) lorsqu’ils sont utilisés pour la phytoextraction d’un site d’étude. Les indicateurs de variations intra et interspécifiques sélectionnés sont les suivants : la biomasse totale, les concentrations en É.T. extraits et les facteurs de translocation (x ̅ pondérée des conc. É.T. dans les parties aériennes / conc. É.T. dans les racines). La contribution des propriétés du sol (degré de contamination, caractéristiques physicochimiques) à la phytoextraction a été évaluée. Les cultivars ont présenté des variations interspécifiques significatives. Cependant, les variations intraspécifiques sur un site d’étude étaient parfois plus importantes que celles mesurées entre les trois différents cultivars. L’amplitude des variations intraspécifiques que présentent le cultivar FISH CREEK sur deux sites d’étude est attribuée à l’influence du pH, de la minéralogie et au contenu en matière organique, lesquelles diffèrent entre les deux sites. Il a aussi été démontré que la phytoextraction des É.T. n’était pas systématiquement corrélée de façon positive avec le degré de contamination. Cela suggère que les concentrations en É.T. mesurées dans le sol ne peuvent pas expliquer à elles seules la variation des concentrations mesurées dans les tissus. L’implication des mécanismes de rétention dans le sol semblent être davantage responsable des variations observées. La compartimentation des É.T. suggère que le saule est efficace pour l’extraction du Cd et du Zn et qu’il est efficace pour la phytostabilisation de l’As, du Cu, du Ni, et du Pb. En ce qui concerne les quantités extraites, le cultivar FISH CREEK semble le plus performant dans la présente étude. / Phytoextraction is a promising solution to the environmental problem of soil contamination by trace elements (TE). This study focuses on intra and interspecific differences (S. purpurea, S. dasyclados, S. miyabeana) of three willow cultivars used for phytoextration of six TE (As, Cd, Cu, Ni, Pb and Zn). The objectives are (i) describe the interspecific variations of FISH CREEK cultivar (S. purpurea) used for phytoextraction on two study sites; and (ii) describe intra and interspecific variations of FISH CREEK (S. purpurea) SV1 (S. dasyclados) and SX67 (S. miyabeana) cultivars used for phytoextraction of a study site. The selected indicators of intra and interspecific variations are : total biomass, TE concentrations extracted and translocation factors (x ̅ weighted TE conc. in aerial parts / conc. TE in the roots). The contribution of soil properties (contamination level, physicochemical characteristics) to phytoextraction was evaluated. The cultivars showed significant interspecific variations. However, intraspecific variations were sometimes more important than variations measured between the three different cultivars grown on one study site. The magnitude of intraspecific variations of FISH CREEK cultivar grown on two study sites is attributed to the influence of pH, mineralogy and organic matter content, which differ between the two sites. It was also shown that the phytoextraction of TE was not consistently correlated positively with the contamination level. This suggests that the TE concentrations measured in soil can not by themselves explain the variation in the measured tissue concentrations. The involvement of retention mechanisms in soil appear to be more responsible for the observed variation. ET compartmentalization suggests that the willow is effective for Cd and Zn extraction and is effective for As, Cu, Ni, and Pb phytostabilisation. Regarding the amount extracted, cultivar FISH CREEK seems the most effective cultivar in this study.
393

Quantification et spatialisation de la contamination en éléments traces métalliques du système fluvio-estuarien girondin / Quantification and spatial distribution of trace element contamination in the Gironde fluvio- estuarine system

Larrose, Aurélie 08 July 2011 (has links)
L’estuaire de la Gironde est affecté par une pollution polymétallique historique provenant de son bassin versant (affluent du Lot). L’analyse de 320 échantillons de sédiments couvrant l’ensemble de la surface estuarienne nous a permis d’établir les premières cartographies à haute résolution spatiale de la contamination métallique des sédiments de surface. Elles révèlent des zones d’accumulation préférentielle des ETM au niveau de la zone des îles en amont de l’estuaire et du chenal nord en aval de l’estuaire. Le facteur de contrôle dominant cette répartition est la granularité des sédiments.L’estimation des stocks métalliques potentiellement re-mobilisables, des facteurs d’enrichissement et de la toxicité potentielle du cocktail des ETM prioritaires nous ont permis d’évaluer un risque de toxicité faible à moyen des ETM vis-à-vis du biota. La contamination en ETM des bassins versants affluents de l’estuaire de la Gironde inclus dans le périmètre du SAGE Estuaire a été appréhendée en couplant sous SIG les caractéristiques typologiques de 57 bassins versants et la géochimie des sédiments prélevés à l’exutoire de ces bassins.Les anomalies les plus importantes concernent les bassins proches de l’agglomération bordelaise et correspondent au cortège des « traceurs urbains » : Ag, Cd, Cu, Hg, Sb et Zn, ainsi que Cu pour les bassins viticoles. L’étude des variations temporelles et spatiales des concentrations en ETM sur les chenaux drainant deux bassins versants agricoles montre des apports ponctuels ou chroniques en Ag,As, Cu et U attribués aux activités anthropiques. Les zones de marais jouent un rôle important dans la spéciation des ETM en lien avec les transformations de la matière organique (e.g. As). Des expérimentations de laboratoire ont permis de caractériser les processus affectant les ETM issus des sols agricoles lors de leur transfert et de leur transport dans les systèmes aquatiques. Les phénomènes de relargage à long terme de Cu soulignent le rôle important des colloïdes organiques dans la mobilité et la biodisponibilité potentielle de cet élément. / The Gironde estuarine system is impacted by historic polymetallic pollution due to mining and smelting activities in the upper watershed. Based on a high spatial resolution sampling strategy, wepropose the first maps of trace element (TE) contamination in the surface sediment at the estuarine scale. The highest TE concentrations occurred in the North Channel in the downstream estuary and inthe island zone in the upper estuary. Estimation of potentially releasable TE fraction, of enrichment factors and a comparison between measured TE concentrations and sediment quality guidelines allow us to class a major part of the estuary as a low to medium priority zone in terms of potential toxicityfor aquatic organisms.The TE contamination in the intra-estuarine watersheds included in a project of water quality management of the Gironde estuary (SAGE), was assessed for 57 watersheds by coupling into GIS,typological characteristics of the watersheds and geochemical analyses of stream sediments. Highest anomalies were found for urban watersheds for which urban tracers were identified as Ag, Cd, Cu, Hg,Sb and Zn, and for vineyard watersheds with Cu. A study of temporal and spatial variations of TEconcentrations in two small agricultural watersheds lead us to identify inputs from point and diffusive sources, especially for Ag, As, Cu and U related to anthropogenic activities. Marsh areas also play an important role in TE reactivity mainly due to organic matter transformations. In laboratory experiments simulating the transportation of TE from agricultural soils to aquatic systems and the maturing process of soil particles in the stream help us to identify processes responsible for TE release in the environment. Long term release of copper was mainly attributed to organic colloid transformation which implies an increase in the mobility, and consequently, the potential bioavailability/toxicity of Cu for aquatic organisms.
394

Phytoremediation of soil contaminated with petroleum hydrocarbons and trace elements

Marchand, Charlotte January 2017 (has links)
The rapid urbanization and industrialization has led to an increase of disposal petroleum hydrocarbons (PHC) and trace elements (TE) into the environment. These pollutants are considered as the most toxic contaminants in the world due to their persistence in the environment, and the long range of toxicological effects for living beings. Recent concerns regarding the environmental contamination have initiated the development of several remediation technologies, including physical, chemical, and biological approaches. In this thesis, gentle soil remediation options (GRO) were investigated at different scales for the reclamation of PHC and TE co-contaminated soil. In the first part of this thesis, laboratory experiments were performed to characterize PHC and TE contaminated soil as well as the indigenous microorganisms (bacteria and fungi) present inside these contaminated soil. It was found that the studied aged contaminated soil had a negative effect on earthworm’s development and L. sativum biomass. Moreover, a high respiration of microorganisms attributed to the transformation/ mineralization of organic matter or/and organic pollutants was observed. This presence of viable microorganisms suggested an adaptation of microorganisms to the contaminant. Further results showed that the long-term exposure of soil microorganisms to high PHC concentration and the type of isolation culture media did not influence the ability of isolates to effectively degrade PHC. However, phylogenic affiliation had a strong on PHC biodegradation. In the second part of this thesis, preliminary studies in greenhouse were assessed to investigate the ability of M. sativa assisted by compost in the greenhouse aided-phytoremediation of PHC and TE. It was found that compost incorporation into the soil promoted PHC degradation, M. sativa growth and survival, and phytoextraction of TE. Residual risk assessment after the phytoremediation trial also showed a positive effect of compost amendment on plant growth and earthworm development. Pilot scale ecopile experiment carried out in the third part of this thesis allow a reduction of up to 80% of PHC and 20% of metals after 17 months. This research demonstrated that M. sativa and H. annus were suitable for phytodegradation of PHC and phytoextraction of TE.  Results from this thesis are helpful for further full-scale phytoremediation studies.
395

The Protracted Magmatism and Hydrothermal Activity Associated with the Gibraltar Porphyry Cu-Mo Deposit, South Central British Columbia, Canada.

Kobylinski, Christopher 01 August 2019 (has links)
The Gibraltar porphyry-Cu deposit is a large open pit porphyry Cu mine in Canada with the geological tonnage (production and reserves) of 3.2 Mt Cu. The Gibraltar deposit is hosted by the Granite Mountain Batholith (GMB), a tonalitic batholith with the surface exposure over 150 km2. All rocks within the batholith are tonalites with minor quartz diorites. The batholith intrudes into mafic volcanoclastic rocks of the Nicola group in the Quesnel terrane of the Canadian Cordillera. The Cu mineralization at Gibraltar is confined to a small 4.5 km2 area in the central part of the batholith and occurs primarily as disseminated chalcopyrite. New U-Pb dating on zircon shows protracted late Triassic magmatism spanning ~25 m.y. for the formation of the GMB. Early magmatism is dated at 229.2±4.4 Ma in unmineralized tonalites. Later, at least three magmatism form the Cu mineralization during a period spanning from 218.9±3.1 Ma to 205.8±2.1 Ma. These fertile magmas form in a more mature arc setting, superseded early barren magmatic activity in a more juvenile arc setting for the bulk of the GMB. Epidote in the GMB shows compositional zoning with Fe-poor cores and Fe-rich rims. The zoning in the mineralized intrusions likely reflects changes in hydrothermal fluid, from S-rich to S-poor. The data from the Gibraltar deposit shows that an economic porphyry Cu deposit may be found in igneous rocks with low Sr/Y in bulk rocks and low Eu/Eu* in zircon. In the Gibraltar deposit, Ce anomalies in zircon reflect oxidation conditions and are correlated with Cu resource associated with their respective intrusion.
396

Le rapport B/Ca des foraminifères : un proxy pour le cycle du carbone dans l’océan / B/Ca ratio of foraminifers : a proxy for the carbon cycle in the ocean

Coadic, Romain 18 December 2012 (has links)
Il a été récemment montré que le rapport B/Ca des foraminifères planctoniques dépend du pH des eaux de surface, tandis que celui des foraminifères benthiques dépend de la saturation en ions carbonates des eaux de fond. Ce nouveau traceur pourrait permettre de mieux contraindre les variations du cycle océanique du carbone, en particulier lors des changements glaciaire-interglaciaires (G/IG) du Pléistocène. Les objectifs de cette thèse étaient donc (1) de développer l’analyse du B/Ca des foraminifères par spectrométrie de masse (ICP-QMS) au LSCE ; (2) d’identifier certains biais potentiels de ce traceur pour en apprécier les limites; et (3) d’appliquer le B/Ca à des reconstructions paléocéanographiques. Les contaminations et la facilité avec laquelle le bore s’adsorbe (effet mémoire) rendent difficile son analyse dans les coquilles de foraminifères où le rapport B/Ca est faible, typiquement compris autour de ~ 40-120 µmol/mol pour les foraminifères planctoniques et ~ 100-250 µmol/mol pour les foraminifères benthiques. Les techniques de nettoyage des foraminifères et d’analyse par ICP-QMS que j’ai employées et améliorées permettent au final de mesurer le B/Ca des foraminifères avec une précision de l’ordre de 3.5%.A partir de l’étude de sédiments de surface prélevés le long d’un profil bathymétrique dans l’Atlantique (Sierra Leone Rise), j’ai pu montrer que la dissolution des tests de l’espèce planctonique Globigerinoides sacculifer se traduit par une perte préférentielle du bore. La dissolution croissante des coquilles de G. sacculifer le long du profil se traduit ainsi par une diminution de ~ 0.1 unités dans les estimations du pH des eaux de surface à partir du B/Ca, un ordre de grandeur similaire aux variations G/IG. Pour s ‘affranchir de cet effet de la dissolution, je propose une procédure de correction basée sur le B/Ca des foraminifères benthiques (ΔCO₃²⁻ des eaux de fond). Cependant, au-delà de l’effet de la dissolution, la reconstruction du paléo-pH des eaux de surface se heurte surtout aux contradictions des études récentes concernant la calibration du coefficient apparent de partition (KD) du bore dans la calcite des foraminifères planctoniques. Pour s’affranchir de la co-variance de la température, de la salinité et du CO₃²⁻ dans les eaux de surface Atlantique, qui peut masquer le(s) facteur(s) important(s) pour la calibration du KD, j’ai réalisé l’analyse du B/Ca de l’espèce Globigerinoides ruber sur des sommets de carottes de l’Atlantique et de l’Indo-Pacifique. Mes données suggèrent qu’il n’y a pas de relation robuste entre le KD et la température ou le CO₃²⁻ des eaux de surface. Pour souligner les incertitudes sur les reconstructions de paléo-pH depuis le dernier stade glaciaire, j’ai effectué une étude de sensibilité basée sur les données B/Ca de l’espèce G. ruber prélevée dans une carotte du Canal du Mozambique et je propose plusieurs pistes pour tenter d’améliorer, à terme, la compréhension du proxy B/Ca dans les foraminifères planctoniques.Si l’utilisation du B/Ca des foraminifères planctoniques est complexe et demande encore un gros travail de compréhension et de calibration, celle du B/Ca des foraminifères benthiques est plus simple, le B/Ca étant directement lié à la saturation en ions carbonates des eaux de fond. L’analyse du B/Ca de Cibicidoides wuellestorfi à travers deux transitions G/IG (MIS16/15 et MIS12/11) au site ODP 849 (Pacifique équatorial) m’a permis de montrer que les changements de la chimie des eaux de fond estimés à partir de traceurs sédimentaires de la dissolution (e.g. teneur en CaCO3, poids et fragmentation des foraminifères,..) ont des amplitudes erronées et présentent des biais temporels. Les profils de B/Ca et du d13C des foraminifères benthiques permettent de mettre en évidence i) le lien entre dégazage océanique de CO2 et préservation des carbonates et ii) la dynamique de la compensation des carbonates sédimentaires marins. / It has been shown recently that the B/Ca ratio of planktonic foraminifers depends on the seasurface water pH, while benthic foraminifer B/Ca depends on the carbonate ion saturation of deep water. This new tracer could allow to better constrain the variations of oceanic carbon cycle, especially during the glacial-interglacial transitions (G/IG) of the Pleistocene. The objectives of this thesis were therefore : (1) to develop the foraminiferal B/Ca analysis by mass spectrometry (ICP-QMS) at LSCE, (2) to identify some potential biases of this tracer to assess its limits and (3) to apply the B/Ca proxy to paleoceanographic reconstructions. Contaminations and the ease with which the boron may be adsorbed (memory effect) make it difficult to analyze it in foraminifer’s shells, which have low B/Ca, typically in the range ~40-120 µmol/mol for planktonic foraminifers and ~100-250 µmol/mol for benthic foraminifers. Foraminifers cleaning techniques and analysis by ICP-QMS that I used and improved now allow the foraminiferal B/Ca measure with an accuracy of about 3.5%. Based upon the study of surface sediments collected along a depth transect in the Atlantic (Sierra Leone Rise), I was able to show that dissolution of the planktonic species Globigerinoides sacculifer results in the preferential loss of boron. The increasing G. sacculifer dissolution with depth of deposition results, therefore, in a ~0.1 units decrease of the seasurface pH estimated from B/Ca, an order of magnitude similar to the expected G/IG variations. To overcome this dissolution effect, I propose a correction procedure based on the B/Ca of benthic foraminifera (bottom water ΔCO₃²⁻). However, the dissolution effect is not the only problem. When trying to reconstruct surface water paleo-pH, we also have to deal with the severe contradictions between recent studies which dealt with the calibration of the apparent boron partition coefficien (KD) in the calcite of planktonic foraminifers. To overcome the co-variance of temperature, salinity and CO₃²⁻ in Atlantic surface waters, which can mask the real important(s) factor(s) for KD calibration, I analyzed the B/Ca of Globigerinoides ruber picked from both Atlantic and Indo-Pacific core-tops. My data suggest that there is no robust relationship between KD and temperature or CO₃²⁻ water surface. To emphasize the uncertainties on the reconstruction of paleo-pH since the last glacial stage, I conducted a sensitivity test based on G. ruber B/Ca data from a Mozambic Channel core. I propose several ways to try to improve our understanding of the B/Ca proxy in planktonic foraminifers. If the use of planktonic foraminifer B/Ca is complex and still requires some dedicated work to understand the problems and improve the calibrations, the use of benthic foraminifer B/Ca is more simple, the B/Ca being directly related to the carbonate ion saturation of bottom waters. Analyses of Cibicidoides wuellestorfi B/Ca through two G/IG transitions (MIS16/15 and MIS12/11) on ODP Site 849 (equatorial Pacific) allowed me to show that changes in deep water chemistry estimated from the sedimentological dissolution proxies (e.g. %CaCO3, foraminifer shell weight and fragmentation, …) display incorrect amplitudes and temporal biases. Based on the comparison of benthic foraminifer B/Ca and δ¹³C, I was able (i) to highlight the link between oceanic CO2 degassing and deep-sea carbonate preservation in the Pacific and (ii) better unravel the dynamics of pelagic carbonate compensation.
397

[en] DEVELOPMENT AND APPLICATION OF METHODOLOGIES FOR THE MULTIELEMENT CHARACTERIZATION OF CONNATE WATERS IN PETROLEUM SAMPLES / [pt] DESENVOLVIMENTO E APLICAÇÃO DE METODOLOGIAS PARA CARACTERIZAÇÃO MULTIELEMENTAR DE ÁGUA CONATA EM AMOSTRAS DE PETRÓLEO

HELOISA MARIA FONTENELLE TEIXEIRA 06 December 2007 (has links)
[pt] O conhecimento da composição química das águas conatas ou de formação é de grande relevância para a produção de petróleo. Atualmente, considera-se a salinidade da água amostrada no aqüífero como representativa de todo o reservatório. Há, entretanto, comprovadas discordâncias e poucas informações sobre a composição química dessas águas. Isso pode levar à estimativa incorreta da reserva de um determinado reservatório, nas previsões de incrustação dos poços e, portanto, nas ações preventivas de elevado custo nos projetos de engenharia. Neste trabalho desenvolveu-se uma metodologia para extração e análise de água conata, a partir de amostras de petróleo. A metodologia se baseia na adição de quantidade conhecida de água sobre um determinado volume de óleo e recuperação dessa água, após separação, para posterior análise. Foram otimizados os parâmetros relevantes para a separação óleo- água, permitindo a recuperação quantitativa de águas associadas, mesmo em concentrações muito baixas (< 0,5%). Estabelecidas as condições, a água extraída foi submetida à análise multielementar por ICP OES e ICP-MS. Os elementos menores e traços determinados apresentaram a seguinte faixa de concentração (em mg L(-1)): Na: 1.880 - 63.794; K- 41,9 - 3.710; Li: 0,48 - 35; Mg: 15,2 - 991; Ca: 143 - 5.867; Sr: 1,12 - 676; Ba: < 0,005 - 243; B: < 0,09 - 149; Zn: < 0,042 - 76,2; Mn: < 0,006 - 4,02; Co: < 0,085 - 465. Os ânions foram determinados por cromatografia iônica, sendo cloreto (4632 - 102.757 mg L(-1)), brometo (2,7- 261 mg L(-1)) e sulfato (15,0 - 3.292 mg (L-1)) os mais abundantes. Os ânions provenientes de ácidos orgânicos, formiato (116 - 7.324 mg L(-1)), acetato (144 - 24.630 mg L(-1)) e propionato (34,3 - 4.891 mg L(-1)), foram investigados também pela técnica de cromatografia iônica em algumas amostras. Na grande maioria das águas extraídas, as concentrações desses cátions e ânions são ordens de grandeza mais altas do que as reportados para água do mar. O excelente balanço iônico calculado para a maioria das águas extraídas (maior ou igual 5%) reforçou a confiabilidade na qualidade analítica dos dados aqui apresentados. Foi otimizada também uma metodologia para pré-concentração de elementos do grupo das terras raras (ETR) através da coprecipitação com hidróxido férrico, a qual permitiu a determinação quantitativa de La, Ce, Nd, Sm, Eu, Gd e Dy nessas águas. O perfil normalizado de concentração desses elementos pelo padrão NASC (North American Shale Composite) mostrou anomalias muito diferentes de água do mar, indicando a potencialidade dos ETR para caracterização geoquímica de águas conatas e dos ambientes geológicos associados. Aperfeiçoou-se também uma metodologia para determinação de elementos menores e traços em petróleo por ICP OES e/ou ICP-MS com introdução de amostra em forma de microemulsão. Ela foi aplicada na análise de óleos e não permitiu apenas a sua caracterização elementar, mas também, um balanço de massa entre a amostra original de óleo e do seu extrato aquoso, o qual se mostrou satisfatório para a maioria das amostras analisadas. Uma vez introduzidas e validadas, as metodologias foram usadas para caracterização de amostras de óleo (e águas associadas), sendo a maior parte proveniente da Bacia de Campos (RJ). Com auxílio de gráficos de correlação, razões elementares e da análise de componentes principais (PCA) foi possível identificar grupos de amostras (águas e óleos) com características comuns (mesmo campo; maior ou menor intrusão de água do mar), mostrando a utilidade destas ferramentas neste e para futuros estudos. / [en] Knowledge on the chemical composition of connate or formation waters is of great relevance in oil production. Presently, the salinity of water sampled from the aquifer is considered generally as being representative of the whole reservoir. This simplification and the few and contradictory results available on the composition of connate water may result in incorrect estimation of the oil production potential of a reservoir, and in the evaluation and use of the cost- intensive actions to prevent scale formation. In this work, a methodology for the extraction and analysis of connate waters from petroleum samples was developed. The extraction method is based on the addition of known quantities of water to the oil sample and its recovery, after phase separation, for subsequent analysis. Relevant experimental parameters were optimized allowing the quantitative separation of water, even when present in very low concentrations (< 0.5%) Once established, the methodology was applied to extracted water samples, which were analyzed by ICP OES and ICP-MS. Minor and trace element content of these waters showed the following range of concentrations (in mg L-1): Na: 1,880 - 63,794; K: 41.9 - 3,710; Li: 0.48 - 35; Mg: 15.2 - 991; Ca: 143 - 5,867; Sr: 1.12 - 676; Ba: < 0.005 - 243; B: < 0.09 - 149; Zn: < 0.042 - 76.2; Mn: < 0.006 - 4.02; Co: < 0.085 - 465. Concentrations of anions (same unit as before) were determined by ion chromatography, being chloride (4,632 - 102,757), bromide (2.7 - 261) and sulfate (15.0 - 3,292) the most abundant ones. Anions of organic acids (also in mg L-1), such as formiate (116 - 7,324), acetate (144 - 24,630) and propionate (34.3 - 4,891) were also determined by ion chromatography in some samples. In most of the extracted water samples, the concentrations of cations and anions were orders of magnitude higher than reported for ocean water. The excellent ionic balance (equal greater or 5%) calculated for most of the extracted waters reinforced our confidence on the reliability of the here produced data. Additionally, a procedure for the preconcentration of rare earth elements (REE) by coprecipitation with iron (III) hydroxide was developed, and which permitted the quantitative determination of La, Ce, Nd, Sm, Eu, Gd and Dy in these waters. Their normalized concentration profile against the NASC (North American Shale Composite) standard showed patterns very different from ocean water, indicating the potential of REE for the characterization connate waters and associated geological environments. A method for the determination of minor and trace elements in oil samples by ICP OES and ICP-MS, after sample preparation by emulsification, was also introduced and applied to the analyses oil samples, allowing the calculation of elemental mass balances between the original oil sample and its aqueous extract, which were satisfactory for most of the samples analyzed. Once established and validated, the methods and procedures were applied to oil samples, mainly for the Campos Basin (RJ). By means of correlation plots, elemental ratios and the Principal Component Analysis (PCA), different groups of waters and oils with common characteristics (same oil field; minor or major intrusion of water) could be identified showing the utility of these tools for this and further studies.
398

Determinação de mercúrio total e orgânico e avaliação dos processos de metilação e desmetilação em sedimentos do reservatório Rio Grande, Estado de São Paulo / Determination of total and organic mercury and evaluation of methylation and demethylation processes in sediments of the Rio Grande Reservoir, State of Sao Paulo

Franklin, Robson Leocádio 28 July 2010 (has links)
O Reservatório Rio Grande, localizado na Região Metropolitana de São Paulo (RMSP), é um importante manancial de abastecimento de água dessa região. Foram analisadas amostras de água de fundo e de sedimentos coletadas nesse reservatório em 4 pontos, em 4 campanhas, de setembro de 2008 a janeiro de 2010, sendo estas quantificadas em relação à concentração de Hg total pela técnica de CV AAS. Em seguida, adaptou-se uma metodologia da literatura para quantificação de Hg orgânico em sedimentos, que consistiu na extração dos compostos organomercuriais com diclorometano em meio ácido e, posterior destruição dos compostos orgânicos com cloreto de bromo. A validação dessa metodologia, em termos de precisão e exatidão, foi realizada por meio da análise dos materiais de referência BCR CRM 580 e IAEA 405. Para avaliação dos mecanismos de metilação e desmetilação de Hg nesse ambiente, foram determinados os seguintes parâmetros físicos e químicos, in situ: pH, temperatura da água, potencial redox (EH), transparência e profundidade. Nos sedimentos foram determinados também a granulometria, carbono orgânico total, bactérias redutoras de sulfato, N total e P total, além de Co, Cu, Fe e Mn. A seleção destes parâmetros esteve relacionada diretamente a fatores que influenciam o comportamento do MeHg em sedimentos e sua zona de transição. Foram encontradas concentrações para Hg total variando entre 1,0 e 71,0 mg kg- 1 e de Hg orgânico entre <10,0 a 47,2 &mu;g kg-1 e taxas de metilação entre 0,06 e 1,4% em sedimentos, ao longo do reservatório. Discutiram-se também as diferentes condições de metilação e suas influências, ao longo do reservatório. Como estudo suplementar, avaliou-se a concentração de outros metais e elementos traço presentes nos sedimentos, por meio da técnica de ativação neutrônica. Foram quantificados os elementos As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc, Zn e os elementos terras raras Ce, Eu, La, Lu, Nd, Sm, Tb e Yb. Os fatores de enriquecimento calculados em relação aos valores da crosta terrestre utilizando-se Sc como elemento normalizador apresentaram valores acima de 2,0 para os elementos As, Br, Sb, U e Zn. Verificou-se uma forte influência antrópica para alguns dos elementos analisados, principalmente nos pontos localizados na entrada do reservatório, que recebem descarga de efluentes domésticos e industriais dos rios que alimentam o reservatório. / The Rio Grande reservoir is located in the metropolitan area of São Paulo and it is a very important water supply for this region. In the present study bottom waters and sediment samples collected in this reservoir, in four sampling points, in four campaigns, from September 2008 to January 2010, were analyzed. Firstly total Hg was determined in sediment and bottom waters by cold vapor atomic absorption technique (CV AAS). Following, the analytical methodology for organic Hg was adapted from literature, where the organomercurial compounds were extracted with dichloromethane in acid medium and subsequent destruction of organic compounds by bromine chloride. The validation of this methodology, in terms of precision and accuracy, was performed by means of IAEA 405 and BCR-CRM 580 reference materials analyses. For methylation and demethylation processes evaluation in this environment, the following physical and chemical parameters were assessed, in situ: pH, water temperature, redox potential (EH), transparency and depth. For the sediment samples, granulometry, total organic carbon, sulphate-reducing bacteria, total N and P, besides the metals Co, Cu, Fe and Mn were evaluated. The selection of these parameters was related to the factors that influence the behavior of MeHg in the sediments and its transition zone. Total Hg ranging from 1.0 to 71.0 mg kg-1 and organic mercury from <10.0 to 47.2 &mu;g kg-1 in sediments and methylation rates from 0.06 to 1.4% were found, along the reservoir. Different methylation conditions along the reservoir and its influences were also discussed. As supplementary study the concentration of some metals and trace elements in the sediments by neutron activation analysis technique was determined. As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc and Zn and rare earth elements Ce, Eu, La, Lu, Nd, Sm and Yb were determined. The enrichment factor in relation to earth crust values using Sc as normalizer element reached values higher than 2.0 for the elements As, Br, Sb, Th, U and Zn, indicating a strong enrichment. A strong anthropogenic influence was verified for some of the elements analyzed, mainly in the points located in the entrance of the reservoir that receives domestic and industrial effluents from the rivers that reach the reservoir.
399

Histórico da deposição de elementos traço na Bacia Amazônica Ocidental ao longo do século XX / Trace elements deposition history in the western Amazon Basin during the 20th century

Correia, Alexandre Lima 17 October 2003 (has links)
Durante o século XX ocorreram modificações importantes no meio ambiente natural em decorrência do desenvolvimento econômico da humanidade. Para estudar o impacto dessas mudanças sobre a América do Sul, um testemunho de gelo de 137 metros foi extraído da Cordilheira dos Andes, na Bacia Amazônica Ocidental, no topo do Nevado Illimani (16°37S, 67°46W, 6350 m altitude). Cerca de 80% da precipitação anual local tem origem direta em massas de ar úmidas provenientes da Bacia Amazônica. Esse testemunho de gelo foi sub-amostrado e analisado em alta resolução temporal, permitindo a interferência de variações ambientais e a caracterização de elementos traço e espécies iônicas presentes no aerossol depositado durante o século XX. Os 50 metros superiores do testemunho foram datados a partir da análise simultânea de variáveis, tais como isótopos estáveis da água, concentração total de alumínio e conteúdo iônico de Ca2+ .Essa seção de 50 metros corresponde ao registro de cerca de 80 anos entre 1919 e 1999. A acumulação de neve no testemunho mostra uma tendência de aumento, variando entre cerca de 17g H2O cm-2 ano-1 em 1919 até 65g H2O cm-2 ano-1 em 1999, Esse aumento concorda com mecanismos de acoplamento dinâmico entre oceano e atmosfera, e resultados observacionais discutidos por Bradley et al. (2003) e Cane ET AL. (1997), sendo compatível com uma redução da temperatura de superfície do mar no Oceano Pacífico Equatorial de cerca de 1,2°C ao longo do século XX, devido ao aquecimento grobal antropogênico. 744 subamostras do testemunho foram analisadas segundo as técnicas de cromatografia iônica, contagem de micropartículas insolúveis, e por espectrometria de massas (Inductively Coupled Plasma Mass Spectrometry) para a obtenção de 45 concentrações elementares entre lítio e urânio. A partir desses resultados, desenvolveu-se uma metodologia para a caracterização química do aerossol depositado em Illimani, que possibilitou a obtenção de estimativas de fluxo de deposição efetivos de elementos traço sobre os Andes ao longo do século XX. Para o cobre, elemento relacionado à exploração mineira da região do Altiplano, o pico histórico de deposição anual devido a fontes antropogênicas foi de cerca de 9,5 x 10-6 kg m-2 em 1981, enquanto o fluxo de deposição natural foi de cerca de 0,2 x 10-6 kg m-2 no mesmo ano. Considerando-se a deposição total de elementos traço em todo o século XX, nota-se que para vários metais pesados ligados a emissões antropogênicas, como níquel, cobre, zinco cádmio, entre outros, os fluxos de deposição naturais representam apenas uma fração minoritária da totalidade dos depósitos. Para esses elementos as atividades econômicas humanas constituem o principal fator responsável por sua mobilização e transporte entre reservatórios naturais no meio ambiente da Bacia Amazônica Ocidental durante o século XX. / Pendant le XX eme siécle plusieurs modifications importantes ont eu lieu dans l\'environement nature/ à cause du développement économique humain. Pour étudier l\'impact de ces modifications sur l\'Amérique du Sud, une carotte de glace 137 metreslong a été récupéré de la Cordillere des Andes, dans le Bassin Amazonien Occidental, au sommet du Nevado Illimani (16°37\'5, 67\'46\'W, 6350 m altitude). Environ 80% de la precipitation annuelle sur le site a comme origine directe des masses d\'air umides du Bassin Amazonien. Cette carotte de glace a été sous-échantilloné et analysé en haute résolution temporelle, ce qui a permis l\'inférence de variations environnementales et la caractérisation des éléments trace et especes ioniques dans l\'aérosol déposé pendant le XXème. Les premiers 50 mêtres de la carotte ont été datés a partir de l\'analyse simultanéede variables, comme les isotopes stables de l\'eau, la concentration totale del\'aluminium, et le contenu ia nique de Ca+2. Cette section de 50 metres correspond àl\'enregistrement d\'environ 80 années entre 1919 et 1999. L\'accumulation du névé dans la carotte montre une tendance d\'augmentation, entre environ 17 g H20 cm2 an1 en 1919 jusqu\'à environ 65 g H20 cm2 an\' en 1999. Cette augmentation est d\'accord avec mécanismes d\'attachement dynamique entre les océans et l\'atmosphere, et résultats d\'observations discutés par Bradley et al. (2003) et Cane et al. (1997), et compatible avec une réduction de la température de swface de la mer dans l\'Océan Pacifique Équatorial d\'environ 1,2°C pendant le XXème, dú au réchauffement global anthropogenique. 744 échantillons de la carotte ont été analysés selon les techniques de chromatographie ionique, comptage de microparticules insolubles, et par spectrométrie de masse (Inductively Coupled Plasma - Mass Spectrometry) pour obtenir 45 profils de concentration élémentaires entre le lithium et l\'uranium. A partir de ces résultats, une méthodologie a été mis au point pour la caractérisation chimique de l\'aérosol déposésur l\'Illimani, ce qui a permis l\'obtention d\'estimations de flux de déposition effectives des éléments trace sur les Andes pendant le XXème. Pour le cuivre, élément associé à l\'exploitation miniêre dans la région de /\'Altiplano, le pie historique de déposition annuel dú aux sources anthropogeniques a été d\'environ 9,5 x 106 kg m2 en 1981, tandis que le flux de déposition naturelle a été d\'environ 0,2 x 1 0\"6 kg m2 dans la même année. Si l\'on considere la déposition totale d\'éléments trace pendant le XXème, on remarque que pour plusieurs métaux lourds liés aux émissions anthropogeniques,comme le niclcel, le cuivre, le zinc, le cadmium, parmi d\'autres, les flux de déposition naturels représentent à peine une fraction minoritaire de la totalité des dépôts. Pour ces éléments, les activités économiques humaines sont le principal facteur responsable pour sa mobilisation et transport entre réservoirs naturels dans l\'environnement du Bassin Amazonien Occidental pendant le XXéme siecle.
400

Análises por LA-ICPMS em zircões de rochas graníticas da Faixa Ribeira no Estado de São Paulo - SE do Brasil: implicações genéticas e geocronológicas / Analytical determinations by LA-ICPMS in zircons from granitic rocks of the Ribeira Belt in the state of São Paulo - SE of Brazil: Genetic and geochronological implications

Andrade, Sandra 10 June 2016 (has links)
Os granitoides da Faixa Ribeira, sudeste do Estado de São Paulo, aparecem como complexas intrusões, aflorando em todos os \"domínios\" geológico-estruturais do embasamento paulista. Neste trabalho, foram avaliados os batólitos Cantareira, São Roque e Itaqui, os plútons Taipas e Tico-Tico, e os turmalina-granitos de Perus, no Domínio São Roque; o batólito Itu e a intrusão Terra Nova (Domínio Jundiaí); o Granito Itaquera (Domínio Embu); o granito da Ilha Anchieta e o charnockito Ubatuba (Domínio Costeiro). Este estudo observa os padrões de evoluções petrogenéticas nos granitoides, com utilização de determinações geoquímicas e isotópicas em rochas e em zircão. A espectrometria de massa (por quadrupolo) associada à ablação a laser (LAQ-ICPMS) foi aplicada para determinar elementos traço em zircão. Dados analíticos de materiais de referência (zircão 91500 e zircão GJ-1) são apresentados no capítulo sobre metodologias. Os dados lito-geoquímicos indicam que as amostras pertencem a linhagens metaluminosas a peraluminosas com elevados teores de K. Granitos metaluminosos (Cantareira, Itaqui, etc.) mostram elevados teores de Sr e da razão Sr/Y, sem anomalia de Eu, em magmas provavelmente formados em profundidade, com granada estável. Os demais granitos mostram-se compatíveis com origem a pressões menores, com plagioclásio estável (anomalia negativa de Eu, baixos teores de Sr). Os zircões, em geral, mostram teores elevados de ETR, Th e U. Os diagramas normalizados de ETR mostram anomalias positivas de Ce, geradas em ambiente oxidante. Os zircões das amostras Tico-Tico, Itu, Terra Nova, Ilha Anchieta, Itaquera, Perus e charnockito Ubatuba apresentam anomalias negativas de Eu, provavelmente determinada pela co-cristalização com plagioclásio. Os elevados teores de ETR e Y nos zircões indicam a atuação de reações acopladas tipo xenotima, com substituição de \'Si POT.4+\' por \'P POT.5+\' e de \'Zr POT.4+\' por\' ETR POT.3+\', \'Y POT.3+\'. O geotermômetro Ti-em-zircão (\'T ANTPOT.zir.\') rendeu, em geral, temperaturas de cristalização equivalentes às temperaturas de saturação de zircão e apatitas em magmas. Zircões com núcleos reabsorvidos e com reflexão escura em CL apresentaram Tzir não realistas, acima de 1000°C, devidas a incorporação exagerada de Ti junto com ETR e P, por influencia de fluidos hidrotermais, que transportam também outros elementos HFS (Nb, Ta, Mo). Os resultados de idades U-Pb em zircão destes granitóides levam a valores entre 580 a 603 Ma, 30 Ma mais jovens que os da literatura. As razões Lu-Hf mostram similaridade entre os protólitos dos granitos São Roque e Itaquera, com uma possível fonte Paleoproterozóica (~2.9 Ga) e com \'épsilon\'\'Hf de -22.8, de elevada residência crustal; as idades TDM (Sm-Nd) estão entre 2.2 e 2.5 Ga, possivelmente representando uma fonte crustal associada a Paleoplaca São Francisco. Para os demais granitoides (Domínios São Roque e Jundiaí) é necessária uma fonte mais radiogênica para os valores de \'épsilon\'Hf (-18 a -11) e \'épsilon\'\'Nd (-12 a -9). As idades TDM, e as mais antigas U-Pb obtidas em alguns núcleos herdados de zircão, indicam fonte constituída por crosta continental juvenil acrescida durante evento vulcânico (por rifteamento) em 1.75 Ga, dentro da placa tectônica, devido a abertura continental, ou mesmo durante eventos ocorridos cerca de 2.1 Ga dentro de Cráton São Francisco. / The granitoids of the Ribeira Belt, southeastern São Paulo state, southeastern Brazil, are found as complex intrusions spread out uniformly in all structural-geologic \"domains\" of the São Paulo basement area. In our work, samples were studied from the Cantareira, São Roque and Itaqui batholiths, the Taipas and Tico-Tico plutons and the Perus tourmaline granites (São Roque Domain), the Itu batholith and the Terra Nova intrusion (Jundiai Domain), the Itaquera granite (Embu Domain), the Ilha Anchieta granite and the Ubatuba charnockite (Costal Domain). This study aims to unravel the pattern of petrogenetic evolution in the granitoids, with the help of geochemical determinations in rocks and zircon crystals. Quadrupole mass spectrometry with laser ablation (LA-Q-ICPMS) was applied to determine trace elements contained in zircons. Analytical data for reference materials (zircons 911500 and GJ-1) are presented in the chapter on Methodology. The lithogeochemical data show that the granites represent meta-aluminous to peraluminous lineages, with significant potash contents. Meta-aluminous samples (Cantareira, Itaqui, etc.) are high in Sr, also with high Sr/Y ratios and no Eu anomalies, representing magmas probably formed at considerable depth, implying garnet stability. The other granites were formed from magmas at lower pressures (stable plagioclase; negative Eu anomaly; low Sr contents). Zircons from these granites contain high REE, U and Th abundances. Normalized REE diagrams present positive Ce anomalies, generated in oxidizing environments. Zircons from Tico-Tico, Itu, Terra Nova, Ilha Anchieta, Itaquera, Perus and the Ubatuba charnockite are characterized by negative Eu anomalies, probably controlled by co-crystallization with plagioclase. The high REE and Y contents in zircons are explained by coupled xenotimetype reactions, with substitution of \'Si POT.4+\' by \'P POT.5+\' and \'Zr POT.4+\' by \'REE POT.3+\', \'Y POT.3+\'. The Ti-in-zircon geothermometer (\'T ANTPOT.zir\') yields, in general, temperatures comparable to the ones obtained with the saturation temperatures of zircons and apatites in magmas. Zircons showing reabsorbed cores and dark reflection areas under CL yield unrealistic temperatures above 1000°C, explained by anomalous uptake of Ti, together with high REE and P contents, on account of hydrothermal fluid activity, also responsible for transporting other HFSE (Ta, Nb, Mo). Dating results with the U-Pb technique in zircons show values between 580 and 603 Ma, 30 Ma younger than results previously published. Lu-Hf ratios suggest similarities for the protoliths of the São Roque and Itaquera granites, with a possible Paleoproterozoic source (~2.9 Ga) and with \'épsilon\'\'Hf of - 22.8, indicating protracted crustal residence time. TDM ages (Sm-Nd) lie between 2.2 and 12.5 Ga, possibly representing a crustal source associated with the São Francisco paleoplate. For the other granitoids (São Roque and Jundiai domains), a more radiogenic source has to be considered, given the \'épsilon\'\'Hf (-18 to -11) and \'épsilon\' Nd (-12 to -9) values. TDM ages, and the older ages obtained with U-Pb on cores of some zircons, point to a source constituted by juvenile continental crust affected by a volcanic event (rifting) at 1.75 Ga, within the tectonic plate, forced by continental opening, or even during events that occurred close to 2.1 Ga within the São Francisco craton.

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