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Modélisation de la dispersion à grande échelle : évolution de laire de répartition passée et future du hêtre commun (Fagus sylvatica) en réponse aux changements climatiques / Dispersal modelling at large scale : evolution of past and future European beech distribution (Fagus sylvatica) in response to climate changesSaltre, Frédérik 14 December 2010 (has links)
Le changement climatique actuel est tellement rapide que la plupart des espèces ligneuses tempérées européennes telles que Fagus sylvatica risquent de ne pouvoir s'adapter, ni migrer suffisamment pour répondre à ce changement. La plupart des modèles simulant l'aire de répartition potentielle de la végétation en fonction du climat considèrent une dispersion « illimitée » ou « nulle » ce qui rend difficile l'évaluation de l'importance de la dispersion par rapport au climat dans la dynamique de la végétation. Ce travail de thèse a pour objectif d'intégrer à un modèle d'aire de répartition basé sur les processus (Phenofit) un modèle phénoménologique de dispersion (modèle de dispersion de Gibbs) dans le but de dissocier l'effet du climat de l'effet de la dispersion dans la réponse de Fagus sylvatica aux changements climatiques en Europe, (i) pendant la recolonisation postglaciaire de 12000 ans BP à l'actuel et (ii) pendant le 21ème siècle. Nos résultats montrent un fort impact de la dispersion associé à un effet également important de la localisation des refuges glaciaires sur la recolonisation postglaciaire du hêtre comparé à l'effet du climat de 12000 ans BP à l'actuel. En revanche, les capacités de dispersion du hêtre ne lui permettent pas d'occuper la totalité de son aire potentielle notamment au nord de l'Europe d'ici 2100. Cette faible colonisation vers le nord de l'Europe associée à de fortes extinctions au sud de son aire de répartition causées par l'augmentation du stress hydrique conduit à une diminution drastique de l'aire de répartition du hêtre d'ici la fin du 21ème siècle. / Current climate change is so fast that some temperate tree species, like Fagus sylvatica, could not adapt nor migrate fast enough to tract their climatic niche. Most models simulating the potential distribution of vegetation as a function of climate consider unlimited or "null" dispersal, which doesn't allow assessing the importance of dispersal compared to climate in the dynamics of the vegetation. In this thesis, we integrate into a process-based species distribution model (Phenofit), a phenomenological model of dispersal (Gibbs-based model) in order to disentangle the effects of climate and dispersal in the response of Fagus sylvatica to climate change in Europe, (i) during the postglacial recolonization from 12000 years BP to present, (ii) during the 21st century. Our results show strong impact of dispersal associated with a strong effect of glacial refugees location on the beech postglacial recolonization, compared to the effect of climat e since 12000 years. Nevertheless, beech dispersal abilities are not sufficient to allow the colonization of newly suitable areas in northern Europe by 2100. This low colonization rate in Northern Europe in addition to a high extinction rate in Southern Europe due to increasing drought lead to a drastic reduction of beech distribution by the end of the 21st century.
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Modélisation du transport des nappes d'hydrocarbures en zone continentale et estuarienne / Numerical modelling of oil spill drifts in continental and estuarine watersGoeury, Cédric 22 October 2012 (has links)
L'application de la Directive Cadre sur l'Eau et l'obligation de surveillance de la qualité d'eau pour la consommation humaine et les activités récréatives ou industrielles, telles que la production d'eau potable, entraînent une forte demande pour des systèmes d'évaluation et de suivi de la qualité de l'eau. Le projet de recherche MIGR'HYCAR (http://www.migrhycar.com) a donc été mis en place pour répondre à un besoin opérationnel et à un défaut d'outils d'aide à la décision adaptés face aux déversements d'hydrocarbures en eaux continentales (rivières, lacs et estuaires) qui représente plus de 50% des déversements accidentels en France. Au cours du projet de recherche MIGR'HYCAR, un modèle mathématique de dérive de nappe d'hydrocarbures, composé d'un modèle lagrangien couplé à un modèle eulérien, a été développé dans la plate-forme hydro-informatique TELEMAC (http://www.opentelemac.org). Le modèle lagrangien décrit le mouvement de la nappe en surface en considérant celle-ci comme un ensemble de particules. Ainsi le modèle développé est capable de modéliser les principaux phénomènes agissant sur une nappe d'hydrocarbures une fois celle-ci déversée : convection, diffusion, échouage, re-largage, étalement, évaporation, dissolution et volatilisation. Bien que le phénomène de dissolution ne concerne qu'un très faible volume d'hydrocarbures, ce processus peut avoir des conséquences importantes du point de vue de la toxicité. Afin de suivre l'évolution du pétrole dissous, un modèle eulérien de suivi de traceurs a été adopté. La quantité de traceur dépend directement de la masse dissoute des particules lagrangiennes. Cette approche permet le suivi des hydrocarbures dissous dans la colonne d'eau. Des cinétiques effectuées en laboratoire ont pour but la calibration du modèle numérique. En complément de cas tests issus de la littérature et de cas réels, des résultats expérimentaux issus d'expérimentations effectuées en canal d'essai doivent permettre de vérifier et valider la qualité des simulations numériques sur des situations où les conditions ne sont que partiellement contrôlées / The application of the European Water Framework Directive on water quality for human consumption and industrial activities creates a need for water quality assessment and monitoring systems. The MIGR'HYCAR research project (http://www.migrhycar.com) was initiated to provide decisional tools for risks connected to oil spills in continental waters (rivers, lakes and estuaries), which represent more than 50% of accidental spills in France. Within the framework of this project, a new numerical oil spill model has been developed, as part of the Telemac hydro-informatics system (see: (http://www.opentelemac.org), by combining Lagrangian and Eulerian methods. The Lagrangian model describes the transport of an oil spill near the free surface. The oil spill model enables to simulate the main processes driving oil plumes: advection, diffusion, oil beaching, oil re-floating, evaporation, dissolution, spreading and volatilization. Though generally considered as a minor process, dissolution is important from the point of view of toxicity. To model dissolved oil in water, an Eulerian advection-diffusion model is used. The fraction of dissolved oil is represented by a passive tracer. This approach is able to follow dissolved hydrocarbons in the water column. Laboratory experiments were conducted to characterise the numerous kinetics of the processes listed above. In addition, meso-scale dynamic experiments in artificial channels and test cases derived from the literature are used to validate the numerical model
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It's Always Better With A Good DMcolannino, david 13 May 2016 (has links)
It’s Always Better With A Good DM is about our relationship with objects and maps as a vector for fantasy. Beginning from the premise that humans understand the world via narrative, I am concerned with the loss of imagination in adulthood in lieu of ideology, which is no more real than stories of future and fantastic places.
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Riverine and coastal ocean contributions to the global and regional oceanic cycling of carbon and nutrientsLacroix, Fabrice 08 July 2019 (has links) (PDF)
Les rivières sont une source importante de constituants biogéochimiques pour les océans. Jusqu’à présent, les modèles océaniques globaux représentaient de manière inadéquate ou ignoraient simplement les apports continentaux de nutriments, de carbone, d’alcalinité provenant des rivières. En particulier, les perturbations anthropiques des apports fluviaux au cours du 20 ème siècle et leurs conséquences sur l’état physique et biogéochimique des océans - notamment la zone côtière - n’ont pas encore été analysées à l’aide d’un modèle global prenant en compte la circulation tridimensionnelle de l’océan. L’objectif principal de cette thèse était donc d’intégrer les apports biogéochimiques provenant des rivières dans un modèle océanique global afin d’améliorer la compréhension du cycle du carbone de l’océan côtier et son évolution au cours du 20 ème siècle. Dans un premier temps, mon travail a visé à l’amélioration des connaissances concernant le rôle des apports biogéochimiques fluviaux sur le cycle du carbone océanique à long-terme, en se focalisant sur la période préindustrielle. Pour cela, j’ai estimé les apports des rivières en utilisant des modèles permettant d’estimer l’érosion chimique et le transfert de matière organique desécosystèmes terrestres à l’océan. Ces apports fluviaux ont ensuite été ajoutés dans le modèle biogéochimique océanique HAMOCC et leurs impacts sur la production primaire océanique et les flux de CO2 entre l’atmosphère et l’océan ont été analysés. Les résultats nous ont permis de quantifier un dégazage de CO 2 préindustriel de 0.23 Pg C yr -1 pour l’océan global, principalement localisé à proximité de l’embouchure des rivières. Le modèle a également démontré l’existence d’un transfert inter-hémisphèrique de carbone, avec un plus grand apport des rivières à l’océan dans l’hémisphère nord, et un transfert de l’hémisphère nord à l’hémisphère sud où un dégazage net se produit. Une augmentation considérable de la production primaire océanique induite par les apports des rivières a également été prédite.La modélisation biogéochimique de l’océan côtier a ensuite été améliorée, en augmentant la vitesse de minéralisation de la matière organique dans les sédiments côtiers et en incluant la dégradation de la matière organique dissoute d’origine terrestre (tDOM) dans l’océan. Par ailleurs, notre analyse suggère un temps de résidence des eaux dans la zone côtière significativement plus courte (14-16 mois en moyenne) que celui estimé jusqu’à présent (>4 ans). Ce temps de courte résidence implique un transfert efficace de matière organiquede l’océan côtier à l’océan ouvert, un état autotrophe net de l’océan côtier, ainsi qu’un puit de CO 2 (0.06-0.08 Pg C yr -1) pour la période préindustrielle, contrairement aux hypothèses précédemment proposées dans la littérature.Dans le dernier chapitre, les perturbations océaniques induites par les changements de la concentration en CO 2 dans l’atmosphère, de la physique de l’océan et des apports biogéochimiques fluviaux au cours du 20 ème siècle ont été analysées. Les résultats indiquent que la réduction de production primaire nette (NPP) observée dans les océans tropicaux et subtropicaux, pourrait être entièrement compensée par une augmentation de la NPP dans l’océan austral et dans les systèmes côtiers de type «EBUS». Les simulations montrent aussi que l’augmentation des apports fluviaux provoque une augmentation de NPP océanique à l’échelle de l’océan côtier (+15 %) et à l’échelle globale (+ 4 %). En conclusion, cette thèse a permis de démontrer l’importance d’inclure la variabilité spatio-temporelle des apports fluviaux et des processus biogéochimiques de l’océan côtier dans la description du cycle du carbone océanique global. Les améliorations apportées au modèle océanique global HAMOCC permettront d’affiner les prédictions du rôle de l’océan dans le cycle du carbone au cours du 21 ème siècle. / River deliver vast amounts of terrestrially derived compounds to the ocean. These fluxes are of particular importance for the coastal ocean, which is recognized as a region of disproportionate contribution to global oceanic biological fluxes. Until now, the riverine carbon, nutrient and alkalinity inputs have been poorly represented or omitted in global ocean biogeochemistry models. In particular, there has yet to be a model that considers the pre-industrial riverine loads of biogeochemical compounds to the ocean, and terrestrial inputs of organic matter are greatly simplified in their composition and reactivities in the ocean. Furthermore, the coastal ocean and its contribution to the globalcarbon cycle have remained enigmatic, with little attention being paid to this area of high biological productivity in global model analysis of carbon fluxes. Lastly, 20 th century perturbations in riverine fluxes as well as of the physical and biogeochemical states of the coastal ocean have remained unexplored in a 3-dimensional model. Thus, the main goals of this thesis are to integrate an improved representation of riverine supplies in a global ocean model, as well as to improve the representation of the coastal ocean in the model, in order to solve open questions with respect its global contributions to carbon cycling.In this thesis, I first aimed to close gaps of knowledge in the long-term implications of pre-industrial riverine loads for the oceanic cycling of carbon in a novel framework. I estimated pre-industrial biogeochemical riverine loads and their spatial distributions derived from Earth System Model variables while using a hierarchy of state-of-the-art weathering and organic matter land-ocean export models. I incorporated these loads into the global ocean biogeochemical model HAMOCC and investigated the induced changes in oceanic biological production and in the air-sea carbon flux, both at the global scale and in a regional shelf analysis. Finally, I summarized the results by assessing the net land sink of atmospheric carbon prescribed by the terrestrial models, and comparing it to the long-term carbon outgassing determined in the ocean model. The study reveals a pre-industrial oceanic outgassing flux of 231 Tg C yr -1 ,which is found to a large degree in proximity to the river mouths. The model also indicates an interhemispheric transfer of carbon from dominant northern hemisphere riverine inputs to outgassing in the southern hemisphere. Furthermore, I observe substantial riverine-induced increases in biological productivity in the tropical West Atlantic (+166 %), the Bay of Bengal (+377 %) and in the East China Sea (+71 %), in comparison to a model simulation which does not consider the riverine inputs.In addition to considering supplies provided by riverine fluxes, the biogeochemical representation of the coastal ocean is improved in HAMOCC, by firstly increasing organic matter remineralization rates in the coastal sediment and by secondly explicitly representing the breakdown process of terrestrial dissolved organic matter (tDOM) in the ocean. In an analysis of the coastal fluxes, the model shows a much shorter residence time of coastal waters (14-16 months) than previously assumed, which leads to an efficient cross-shelf transport of organic matter and a net autotrophic state for both the pre-industrial timeframe and the present day. The coastal ocean is also revealed as a CO2 sink for the pre-industrial time period (0.06-0.08 Pg C yr -1 ) in contrary to to the suggested source in published literature. The sink is however not only caused by the autotrophic state of the coastal ocean, but it is likely also strongly influenced by the effects of biological alkalinity production, as well as both physical and biogeochemical characteristics of open ocean inflows.In the final chapter, 20 th century oceanic perturbations due to changes in atmospheric CO 2 concentrations and in the physical climate, and to increases in riverine nutrient supplies were investigated by using sequential model simulations. The model results show that the decrease in the net primary production (NPP) in the tropical and subtropical oceans due to temperature-induced stratification may be completely compensated by increases in the Southern Ocean and in Eastern Boundary Upwelling Systems (EBUS). The model also reveals that including increases in riverine supplies causes a global ocean NPP increase of +4 %, with the coastal ocean being a particularlystrongly affected region (+15 %).This thesis shows a strong necessity to represent spatio-temporal changes in riverine supplies and of the coastal ocean state in spatially explicit global models in order to assess changes of the global cycling of carbon in the ocean in the past and potentially in the future. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
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Current atherosclerosis of intracranial and extracranial vessels in ischemic stroke patients. / CUHK electronic theses & dissertations collectionJanuary 2011 (has links)
Racial differences in the distribution of cerebrovascular occlusive disease are well documented. Extracranial stenosis is more common in Caucasian while intracranial stenosis is more common in Asian, Hispanic and African-American. The prevalence of asymptomatic intracranial stenosis in middle age and elderly general population in China was about 7%. The frequency of intracranial atherosclerosis among patients with stroke and TIA is 40 to 50% in Chinese populations. Concurrent extracranial and intracranial stenoses is common in Asian, the incidence range from 10 to 39% in patients with stroke. The current population of China is 1.3 billion and it was estimated that 30% of the population will be aged 60 and above by 2050 in China. The incidence of stroke in China is 215 per 100000 which is one of the highest among the world and this burden is expected to escalate in the coming decades. However, studies of concurrent stenoses among Chinese are scarce. The aim of this precis is to present my studies that were conducted mainly among Chinese stroke patients on this particular field. The scope of the studies covers the following 4 areas: (1) Identification of Long-term prognosis of patients with concurrent stenoses; (2) Long-term prognosis of patients with concurrent stenoses and ischemic heart disease; (3) Lesion pattern and stroke mechanisms in concurrent stenoses; and (4) genetic polymorphisms of ischemic stroke patients with concurrent stenoses. The background, objectives, subjects, methods, results, and conclusions of these studies will be presented in this precis. / Man, Bik Ling. / Adviser: Lawrence K.S. Wong. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 144-184). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
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Estudio de la relación entre la reputación corporativa de un banco peruano, la satisfacción y la fidelización del cliente: estudio del caso BBVA ContinentalCerrón Baquerizo, Cristopher, Cervantes Cahua, Vania Elizabeth, Chávez Maldonado, Ximena 22 January 2019 (has links)
La presente investigación tiene como objetivo principal analizar la relación entre la
reputación corporativa, la satisfacción y la fidelización del cliente del BBVA Continental. Hoy
en día, la reputación corporativa constituye uno de los activos intangibles más valorados en las
grandes compañías, y es por ello que surge el interés por analizar y profundizar en este concepto
tomando en cuenta a los clientes como el principal stakeholder de una empresa de servicios
financieros. Asimismo, se toma en cuenta la influencia de la reputación sobre la experiencia
satisfactoria de compra y la intención de continuar siendo clientes del banco.
El caso de estudio es el BBVA Continental, el cual es uno de los principales bancos del
Perú y actualmente, es una de las entidades financieras más valorada por los peruanos y líder en
reputación según los rankings más importantes del país. Por tanto, lo que se busca es resaltar la
importancia de la reputación corporativa de la compañía conociendo su influencia sobre los
factores de satisfacción y fidelización teniendo como input la percepción de sus clientes.
La investigación se estructura estableciendo en primer lugar, los objetivos e hipótesis
planteadas; luego, se establece el diseño de la metodología con un enfoque mixto, tomando en
cuenta el análisis de información cualitativo y cuantitativo, siendo este último, fundamental para
obtener los hallazgos y resultados del estudio. En la investigación, se toma como referencia un
modelo puesto a prueba en otra industria del sector servicios, para que, con éste, se realice un
estudio confirmatorio en el sector bancario en el Perú. El análisis cuantitativo se lleva a cabo a
través de un modelo de ecuaciones estructurales, el cual permite conocer de qué manera, los
clientes encuestados, valoran los indicadores relacionados a la reputación, satisfacción y
fidelización.
Para lograr obtener la información necesaria, se realizaron entrevistas a expertos y
representantes del BBVA Continental, además de la aplicación de un cuestionario a los clientes
del banco. A través de estas herramientas, se logra obtener la información necesaria sobre la
percepción de los clientes para, posteriormente, contrastar con lo obtenido en las entrevistas.
En el análisis de resultados se logra comprobar que las hipótesis sobre las relaciones entre
las tres variables principales estudiadas sí existen y están presentes en el caso estudiado. Los
hallazgos permiten determinar que la relación entre la reputación corporativa y la satisfacción del
cliente es directa, lo mismo sucede con la relación entre la satisfacción y la fidelización del cliente
y, por último, la relación entre la reputación corporativa y la fidelización. / Tesis
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Ambientes de sedimentação mista (siliciclástica e carbonática), cicloestratigrafia e halocinese durante o Albiano, Plataforma de Regência, Bacia do Espírito SantoTagliari, Claudio Vinicius 27 September 2013 (has links)
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Previous issue date: 2013-09-27 / Nenhuma / Esta tese buscou definir a origem das rochas carbonáticas, mistas e siliciclásticas albianas da Plataforma de Regência que ocorrem na porção submersa da Bacia do Espírito Santo. Para alcançar esse objetivo, algumas hipóteses foram testadas: houve algum fator controlando a alternância cíclica de camadas de rochas carbonáticas, híbridas e siliciclásticas e, em caso positivo, que fator seria esse? Qual teria sido a origem da boa preservação da ciclicidade em um contexto deposicional transicional/marinho raso, dominantemente siliciclástico, dinâmico e de alta energia e sujeito a frequentes eventos erosivos? Os sistemas deposicionais siliciclásticos, mistos e carbonáticos coexistiram de forma ativa na escala de alta frequência? Para que estes questionamentos fossem respondidos buscou-se definir: (1) o modelo deposicional/paleoclimático adequado para explicar a sucessão vertical e lateral de fácies; (2) a origem da alternância cíclica; (3) a influência da tectônica, tanto envolvendo o embasamento como vinculada à halocinese, na deposição e preservação da sucessão estudada; e (4) o contexto paleogeográfico (escala regional) e estratigráfico (escala das fácies) ao qual a sucessão analisada se associa. Para tanto, foram utilizados dados de sísmica 3D e de poços (perfis, 180 m testemunhos e amostras de calha) a partir dos quais se geraram seções sísmicas e estratigráficas, mapas de litofácies e paleogeográficos, e bloco-diagramas. Foi evidenciada uma reativação eoalbiana do Falhamento Cedro-Rio Doce que dividiu a Plataforma de Regência em um bloco alto, a oeste, e outro baixo, a leste. Esse fenômeno causou uma remobilização parcial de cunho halocinético da sequência deposicional mais antiga (Sequência A) no sentido do depocentro da bacia. Nessa sequência foram descritas 14 litofácies organizadas em 8 associações de fácies que representam distintos intervalos estratigráficos e ratificam o caráter alocíclico da sedimentação. Foi apresentado um modelo paleoambiental capaz de explicar a sucessão vertical dos distintos tipos litológicos no interior de um “ciclo sedimentar ideal” de alta frequência bem como a disposição espacial dos principais tipos litológicos na escala das sequências deposicionais e tratos de sistemas de 3ª ordem. A análise espectral de perfis de raios gama, previamente correlacionados a dados litológicos de poço, confirmou a origem alocíclica (excentricidade curta) dos estratos investigados bem como permitiu estabelecer o tempo envolvido na deposição do pacote sedimentar estudado, demonstrando-se, assim, constituir-se em um poderoso geocronômetro capaz de determinar o intervalo de tempo transcorrido durante a acumulação com maior resolução que aquela alcançada pelo tradicional método paleontológico. É sabido que ambientes transicionais e plataformais são submetidos a eventos de alta energia e a variações significativas do nível de base, o que dificulta a boa preservação dos estratos depositados, e, assim, da ciclicidade. Nesse sentido, a boa preservação da ciclicidade no intervalo analisado foi vinculada a escape de sal, provocando, um incremento na acomodação, pelo menos em parte devido a altas taxas de acumulação siliciclástica. / The main goal of this thesis is to define the origin of the carbonate, hybrid and siliciclastic Albian rocks of the Regência Platform that occur in the offshore portion of the Espírito Santo Basin. To achieve this objective, the following hypotheses were tested: was there any external control on the cyclic arrangement of the carbonate, hybrid and siliciclastic strata and, if so, of which sort? What would have favored the excellent preservation of the cyclicity within a transitional to shallow marine, dynamic and high energy depositional setting? Did the siliciclastic, mixed and carbonate depositional systems co-exist at the high-frequency scale? To explain these questions, it was required to define (1) a depositional/paleoclimate model that properly explain both vertical and lateral facies changes; (2) the origin of the cyclicity; (3) the influence of basement and salt tectonics in the deposition and preservation of the studied interval; and (4) the paleogeographic (regional scale) and stratigraphic (facies scale) setting ascribed to the studied interval. The data set includes 3D seismic and well data (logs, cores and cuttings) from which seismic and stratigraphic sections, lithofacies and paleogeographical maps, and block-diagrams were derived. A reactivation of the Cedro - Rio Doce Fault Zone during the Eo-Albian divided the Regência Platform into a high (to the West) and a low (to the East) block. This event has also caused the partial displacement of the older studied interval (Sequence A) to the basin depocentre due to halokinesis. Based on 180m of cores obtained from distinct stratigraphic intervals within Sequence A, 14 lithofacies were distinguished and organized into 8 facies associations whose superposition confirmed the allocyclic nature of the facies succession. It was presented a depositional model able to explain the vertical succession of lithologies within a high-frequency “ideal sedimentary cycle” as well as the regional arrangement of the main lithologies at the 3 rd order scale. The spectral analysis of the gamma-ray logs previously tied to lithological information from well data confirmed the allocyclic nature (short eccentricity) of the cyclicity as well as has allowed establishing the time interval recorded in the studied interval. This later result demonstrates that this approach can be used as a powerful geochronometer able to quantify the time span of a sedimentary succession in a higher resolution than the traditional paleontological method. It is well known that shelfal and transitional environments are subject to high energy episodes and large sea-level changes that lessen the depositional preservation potential and so the cyclicity record. In this context, the excellent preservation of the cyclicity within the studied succession was ascribed to the high siliciclastic sedimentation rate favoring salt escape and increasing accommodation.
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O magmatismo de Arco Continental Pré-Colisional (790 Ma) e a reconstituição espaço-temporal do regime transpressivo (650 Ma) no Complexo Várzea do Capivarita, Sul da Província MantiqueiraMartil, Mariana Maturano Dias January 2016 (has links)
Este estudo foca no Complexo Várzea do Capivarita (CVC), localizado no sul da Província da Mantiqueira (PM), Brasil. A fim de investigar a evolução geológica do CVC, uma abordagem multi-disciplinar foi utilizada, incluindo geologia de campo, geologia estrutural, petrografia, geoquímica de elementos maiores e traços, isótopos de Sr-Nd e geocronologia U-Pb em zircão (LA-MC-ICP-MS e SHRIMP). O complexo compreende uma variedade de orto- e paragnaisses de composição e idade diversa. Volumes subordinados de sienitos sintectônicos também perfazem o CVC. A deformação é particionada em zonas de cisalhamento do tipo thrust (D1) e transcorrentes (D2), o que sugere tectônica transpressiva. O arcabouço estrutural descrito é possivelmente relacionado a um evento colisional oblíquo. Os estudos petrológicos e geocronológicos enfatizaram os ortognaisses do CVC a fim de avaliar as fontes magmáticas e paleo-ambientes envolvidos. Idades de cristalização obtidas nos domínios de zircão com zonação tipicamente ígnea variaram entre 780 e 790 Ma. Por sua vez, idades entre 640 - 650 Ma foram obtidas em sobrecrescimentos de zircão, sendo interpretadas como o registro da idade do metamorfismo de alto grau e fusão parcial associada. Os dados geocronológicos apresentados também indicaram que ambos os regimes cinemáticos foram contemporâneos, oferecendo, dessa forma, evidencia adicional para a hipótese de colisão oblíqua. Os ortognaisses do Complexo têm composição tonalítica a granítica e são rochas calcioalcalinas meta- a peraluminosas, com razões elevadas de 87Sr/86Sr (i) variando de 0.71628 a 0.72509 e valores εNd (790) entre -7.19 a -10.06. Sua composição e padrões de elementos traços sugerem que representem um magmatismo de arco maduro continental. O magmatismo registrado no CVC é compatível com outras sequências de arco de ca. 800 Ma, incluindo parte das metavulcânicas ácidas do Complexo Metamórfico Porongos (CMP) e os ortognaisses do Cerro Bori, Uruguai. Todas essas associações têm assinatura típica de orógenos acrescionários, contendo idade TDM Meso a Paleoproterozóica, além de forte evidência da participação de proscessos de assimilação crustal/ contaminação. Desta forma, o conjunto de dados apresentados permite interpretar essas associações como parte do mesmo magmatismo, ou pelo menos como fragmentos de arcos magmáticos similares. As assinaturas Sr-Nd e geoquímica sugere que ao menos parte das metavulcânicas do CMP represente os protólitos dos ortognaisses de alto grau inclusos no CVC. Adicionalmente, as evidencias isotópicas também apontam similaridade entre as rochas sedimentares de ambas as unidades, sugerindo que o CVC e o PMC são, ao menos em parte, expressões do mesmo contexto, onde a atividade magmática e sedimentar ocorreu em um mesmo ambiente de arco continental. A corroboração desta premissa é o objetivo principal de estudos de proveniência em andamento, cujos resultados prévios apontam para o caráter vulcano-sedimentar dos metapelitos do CVC e sua relação co-genética com os ortognaisses do CVC. Os dados isotópico Sr-Nd sugerem que os protólitos dos ortognaisses foram gerados por processos de assimilação crustal associados à cristalização fracionada. O modelamento binário (binary mixing model) realizado indica que o magmatismo estudado teria se originado de fontes mantélicas do tipo EM II. Uma seqüência paleoproterozóica de rochas TTG pertencente ao Complexo Arroio dos Ratos (CAR) é possivelmente o principal contaminante crustal assimilado. Em conjunto com as idades de herança descritas no CVC em ca. 2.0 Ga é sugerido que a fusão crustal que gerou o magmatismo do CVC em ca. 790-780 Ma foi predominantemente similar ao CAR. / This study focuses in the Várzea do Capivarita Complex (VCC), exposed in the southern part of the Neoproterozoic Mantiqueira Province (PM), Brazil. To investigate the evolutionary processes that lead the VCC construction, a multidisciplinary approach is taken, which includes field and structural geology, petrography, major and trace-element geochemistry, Sr-Nd isotope and U-Pb zircon geochronology by LA-MC-ICP-MS and SHRIMP. The complex comprises a compositional and age variety of ortho- and paragneisses tectonically interleaved during a high grade event. Subordinate volumes of syntectonic syenites are also part of CVC. The VCC deformation is partitioned into thrusting (D1) and transcurrent (D2) shear zones, suggestive of transpressive tectonics. This structural framework is possibly related to an oblique collision event. Petrological and goechronological studies emphasize the VCC orthogneisses in order to evaluate magmatic sources and related paleo-environments. Igneous crystallization ages obtained in the typical magmatic domains presenting oscillatory zoning in zircons vary between 780 and 790 Ma. Zircon overgrowths have ages mostly in the 650 – 640 Ma range and are interpreted to record the timing of high-grade metamorphism and associated partial melting. Geochronological data presented also indicates that boths kinematic regimes are contemporaneous, offering, therefore, further evidence for the oblique collisional event hypothesis. The VCC ortogneisses comprise tonalitic to granitic compositions and are metaluminous to peraluminous, calc-alkaline rocks, with high 87Sr/86Sr (i) ratios from 0.71628 to 0.72509 and εNd (790) values from -7.19 to -10.06. Their geochemical composition and trace-element patterns are compatible with a continental mature arc. VCC magmatism is correlated with other ca. 800 Ma arc sequences from southern PM, including part of the Porongos Metamorphic Complex (PMC) metavolcanic rocks and the orthogneisses from Cerro Bori, Uruguay. All these associations show signatures typical of accretionary orogens, TDM and Meso to Paleoproteroic inheritance ages, and present strong evidences of crustal assimilation/contamination. Thus, these sequences may be interpreted as part of the same magmatism, or at least as fragments of similar magmatic arcs. Geochemical and Sr-Nd signatures suggest that at least part of the PMC metavolcanic rocks may represent the protoliths of the VCC high grade orthogneisses. This, together with the isotope evidence of similarity between the sedimentary fractions of both unities, suggest that the VCC and PMC are, at least in part, expressions of the same context, wherein the magmatic and sedimentary activity occurred in a single continental arc environment. The corroboration of this premise is the main goal of provenience studies in prep, which previous results points to the volcano-sedimentary character of part of the VCC metapelites and its co-genetic relation with the VCC orthogneisses. Sr-Nd isotope data suggest that the orthogneiss protoliths were generated by crustal assimilation processes associated with fractional crystallization. Binary mixing models indicate that the VCC magmatism originates from evolved EM II mantle sources. A Paleoproterozoic TTG association (ca. 2.0 Ga) from the Arroio dos Ratos Complex (ARC) seems to be the main crustal contaminant assimilated. Together with the small inheritance contribution at ca. 2.0, this suggests that the melted crust at ca. 790-800 Ma was predominantly like ARC.
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Entre validade e faticidade: a jurisprudência como via de acesso e construção do conceito de sistema jurídico continental / Between validity and facticity: the jurisprudence as a way of acess and construction of the concept of continental civil law systemLong, Chen Chieng 20 April 2011 (has links)
O fenômeno do ativismo jurisdicional tem como causa a crise do direito. Uma releitura do tema a partir de uma perspectiva existencial permite concluir que sua origem assenta-se na perda do sentido da ocupação e preocupação do homem em relação ao direito. Esta crise articula-se, grosso modo, em dois níveis distintos. De um lado, pelo desgaste do modelo de racionalização contido na proposta da tripartição de poderes de Montesquieu; de outro, na perda do sentido do direito como forma de controle social no processo de incorporação da armação da técnica. Diante da anomia do legislador e do Estado aos desafios atuais em torno do direito, presencia-se, na atualidade, o aumento do ativismo jurisdicional na definição do conteúdo do direito continental. Dentro das possibilidades abertas no horizonte da experiência histórica, a evolução do direito continental permite constatar que esta se formou e perpetua-se a partir dos conceitos antagônicos de mutabilidade (em ajuste às necessidades da evolução da sociedade), mas também de segurança jurídica (representada pela norma posta). Um aumento do ativismo jurisdicional que pretenda preservar a experiência da tradição do direito continental exige que a ocupação e preocupação em torno do Direito se deem em aderência à experiência compartilhada dentro do mundo das vivências e no fino equilíbrio dos conceitos de normas sociais e de garantia, sem o que, no extremo da projeção do Dasein no horizonte de sua injunção social, teríamos inevitavelmente um processo de ruptura conceitual da experiência do Direito ou a anulação do Dasein perante o Direito. / The phenomenon of the jurisdictional activism is caused by the crisis of law. A re-reading of the theme from an existential perspective allows for the conclusion that its origin is based on the loss of mans care and concern sense regarding the law. Broadly, this crisis articulates in two distinct levels. On one side, by the rationalization model exhaustion contained in the tripartite division of powers proposed by Montesquieu; on the other side, in the loss of law sense as a way of social control in the incorporation process of the frame of the technique. As a consequence of the anomy of the legislature branch and the State to the current challenges around the law, the increase of the jurisdictional activism in the definition of the continental law content can be contemporarily noticed. Within the possibilities opened in the historical experience scope, the evolution of the continental law allows for the observation that it was formed and continues from the antagonistic concepts of mutability (adjusted to the evolution needs of the society), but also of legal security (represented by the rule provided for). An increase of the jurisdictional activism intending to preserve the experience of the continental law tradition requires that the care and concern concerning the law comply with the experience shared within the world of experiences and in the fine balance of the social rules and guarantee concepts, without which, in the extreme of the Dasein projection in the scope of its social injunction, we would inevitably have a process of conceptual rupture of the law experience or annulment of Dasein before the law.
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Evolution of oceanic margins : rifting in the Gulf of California and sediment diapirism and mantle hydration during subductionMiller, Nathaniel Clark January 2013 (has links)
Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references. / This thesis investigates three processes that control the evolution of oceanic margins. Chapter 2 presents seismic images of a ~2-km-thick evaporite body in Guaymas Basin, central Gulf of California. In rifts, evaporites form under conditions unique to the latest stages of continental rupture, and the presence, age, thickness, and shape place new constraints on the history of early rifting there. Chapter 3 presents numerical experiments that show that diapirs can form in sediments on the down-going plate in subduction zones and rise into the mantle wedge, delivering the sedimentary component widely observed in arc magmas. Chapter 4 presents measurements of seismic anisotropy from wide-angle, active-source data from the Middle America Trench that address the hypothesis that the upper mantle is hydrated by seawater flowing along outer-rise normal faults. These measurements indicate that the upper mantle is ~1.57 to 6.89% anisotropic, and this anisotropy can be attributed to bending-related faulting and an inherited mantle fabric. Accounting for anisotropy reduces previous estimates for the amount of water stored in the upper mantle of the down-going plate from ~2.5 to 1.5 wt%, a significant change in subduction zone water budgets. / by Nathaniel Clark Miller. / Ph.D.
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