La naissance de la Lune, il y a environ 4.35-4.55 Ga, fut le résultat d'une collision majeure entre la proto-Terre et un embryon planétaire de la taille de Mars. L'énergie cinétique libérée lors de cet impact "géant" a sans doute été suffisante pour engendrer la fusion totale du manteau terrestre sur une profondeur de plusieurs milliers de kilomètres. La première croûte et réservoirs mantelliques différenciés furent ainsi produits par cristallisation de cet océan magmatique, avant d'être en grande partie réhomogénéisés par le recyclage crustal et le mélange convectif. Ce projet vise à apporter de nouvelles contraintes sur la chronologie et les mécanismes précoces (>4 Ga) de différenciation du manteau et de la croûte terrestres. A cet effet, une approche multi-isotopique combinant les systèmes 146,147Sm-142,143Nd et 176Lu-176Hf a été appliquée aux roches mafiques et ultramafiques de l'assemblage de Nulliak (3.78 Ga, Bloc de Saglek, Labrador) et de la ceinture supracrustale d'Ukaliq (3.75 Ga, Craton du Supérieur, Québec). L'application du système couplé 146,147Sm-142,143Nd aux échantillons de cette étude a permis de déterminer précisément l'âge de différenciation de la Terre silicatée, à 4.40±0.03 Ga. Cet âge est similaire à celui des plus anciennes roches lunaires, et légèrement antérieur à l'âge de cristallisation de l'océan magmatique lunaire (4.36±0.03 Ga). Les signatures 142,143Nd observées dans les roches Eoarchéennes de Nulliak et les laves Néoarchéennes de Theo's Flow (2.7 Ga, Abitibi) sont remarquablement similaires, et suggèrent une source mantellique commune, différenciée il y a ~4.4 Ga et préservée du mélange convectif sur une échelle de temps de plusieurs milliards d'années. L'application de la systématique 176Lu-176Hf aux metakomatiites de Nulliak indique que leur manteau source était caractérisé par des rapports Lu/Hf et Sm/Nd superchondritiques, impliquant un épisode antérieur de différenciation dans le champ de stabilité du grenat (P=3-25 GPa). De manière plus générale, il apparaît que l'ensemble des komatiites Eo- et Mesoarchéennes définissent une corrélation εHf-εNd de pente distincte (~4) à celle de la corrélation εHf-εNd du manteau moderne (~1.5). Cette signature est caractéristique d'une différenciation mantellique en présence de grenat et ne peut être attribuée à la cristallisation de pérovskite aux pressions du manteau inférieur. L'ensemble de ces observations est interprété comme reflétant une différenciation du manteau supérieur lors de la phase finale de cristallisation de l'océan magmatique, suivi du recyclage de ces cumulats superficiels dans le manteau profond par un mécanisme d'overturn. L'enregistrement isotopique Archéen en 142Nd pourrait ainsi refléter un échantillonnage ponctuel de ces hétérogénéités primordiales dans des contextes de points chauds au cours des deux premiers milliards d'années de l'histoire de la Terre / The Earth is a telluric planet that formed by collision with and accretion of multiple differentiated proto-planetary bodies. The latest of these collisions, the Moon-forming impact, occurred between the proto-Earth and a Mars-sized impactor ~4.35-4.55 Ga ago. Kinetic energy released during impact likely induced global melting of the silicate Earth over depths of thousands of kilometers. Crystallization of this magma ocean then resulted in the differentiation of primordial crustal and mantle reservoirs that were subsequently rehomogenized by convective stirring. The aim of this project is constrain the timing and differentiation mechanisms of the early silicate Earth (>4 Ga ago), using a multi-isotopic approach combining coupled 146,147Sm-142,143Nd chronometry and 176Lu-176Hf systematics. These isotopic tools were used to study well-preserved mafic to ultramafic rocks from the Nulliak assemblage (3.78 Ga, Saglek block, Labrador) and from the Ukaliq Supracrustal Belt (3.75 Ga, Superior Province, Quebec). Application of coupled 147Sm-143Nd and 146Sm-142Nd systematics to Archean rocks from this study provides a precise differentiation age of 4.40±0.03 Ga for the early silicate Earth. This event predates the final stage of magma ocean solidification on the Moon by <50 Ma, consistent with near synchronous cooling of terrestrial and lunar mantles in the aftermath of the giant impact. Furthermore, the similarity of 142,143Nd signatures between the Eoarchean Nulliak metakomatiites and Neoarchean lavas from Theo's flow (2.7 Ga, Abitibi) suggests that their parent magmas were derived from a common mantle source. This depleted mantle reservoir differentiated 4.4 Ga ago and remained isolated from mantle mixing on a billion year timescale. Application of 176Lu-176Hf systematics to Nulliak metakomatiites indicates extraction from a source with both suprachondritic ratios of Lu/Hf and Sm/Nd, consistent with prior depletion at shallow depth in the garnet stability field (P=3-25 GPa). Collectively, Eo- and Meso-Archean komatiites define an ε176Nd-ε143Nd array with a slope of ~4, significantly distinct from that of the modern mantle array (~1.5). This signature requires differentiation in the presence of garnet and cannot be attributed to crystallization of a perovskitic assemblage in a deep magma ocean (P>25 GPa). We interpret our observations to reflect differentiation of shallow cumulates during the final stage of magma ocean crystallization, followed by overturn and foundering of these dense cumulates in the deep mantle. The Archean 142Nd record may thus primarily reflect episodic sampling of these primordial heterogeneities by hot mantle plumes rather than progressive mixing of highly depleted Hadean reservoirs

O crescimento acelerado das cidades associado à ausência, inadequação ou ineficácia do planejamento urbano, no Brasil, tem acarretado o desequilíbrio dos sistemas ambientais e a imposição de riscos a parcelas significativas da população. Muito embora as numerosas críticas aos modelos de planejamento aplicados no País, o urbanismo continua desempenhando um papel fundamental na organização e desenvolvimento das cidades. A leitura e avaliação das potencialidades e limitações do meio físico urbano são essenciais ao processo de planejamento, organização e controle do uso do solo; sendo assim, a cartografia geotécnica desempenha um papel de relevância no enfrentamento dos problemas inerentes à ação do homem sobre o meio físico. Mas, apesar do considerável desenvolvimento da cartografia geotécnica nacional, ainda são necessários avanços no que se refere à sua aplicação ao ambiente urbano e ao planejamento, bem como uma melhor adequação à realidade econômica e instrumental da maioria dos municípios brasileiros, em especial os de médio e pequeno porte. O presente trabalho pretende contribuir com o desenvolvimento de instrumentos de auxílio ao planejamento do crescimento sustentável da cidade, através da estruturação de um procedimento progressivo de mapeamento geotécnico que incorpora a análise do crescimento da cidade como etapa de seu desenvolvimento. Aplicado ao município de Pelotas/RS, o método tem por base o uso de dados pré-existentes e objetivou a produção de mapas de suscetibilidade e da carta de aptidão à urbanização, aplicáveis ao planejamento territorial urbano Partindo da etapa de inventário e passando pela fase de preparação e geração de dados, o mapeamento foi desenvolvido através da etapa geral e de semi-detalhe do método progressivo, nas quais os atributos do meio físico foram cruzados por meio de análise multivariada e uso de Sistema de Informações Geográficas. O mapeamento dos vazios urbanos e a modelagem e simulação do crescimento da cidade permitiram o direcionamento das etapas finais de mapeamento e a redução das análises geotécnicas às áreas territoriais de urbanização futura, reduzindo esforços e otimizando o processo como um todo. A aplicação do método produziu um grande número de informações, mapas, cartas e caracterizações do meio físico, com larga possibilidade de utilização no planejamento do crescimento futuro da cidade e na implantação de medidas corretivas aos problemas e conflitos decorrentes do processo de urbanização passada. Os resultados alcançados indicam tanto a validade da metodologia para o estudo em particular, quanto seu potencial de utilização, parcial ou total, a outras realidades fisiográficas. Através da contraposição da legislação urbanística, do processo de crescimento da cidade e dos produtos do mapeamento, foi possível concluir que a inexistência da informação geológico-geotécnica foi determinante na ocupação de áreas de muito baixa e baixa aptidão à urbanização na zona urbana do município de Pelotas. Tal constatação reforça, assim, a importância do uso da informação geológicogeotécnica no planejamento e na gestão urbana nacional. / The accelerated growth of towns associated with the absence, inadequacy or low efficiency of urban planning in Brazil has caused changes of environmental systems and the imposition of risks to significant portions of the population. Despite the numerous criticisms of the planning models applied in the country, urban planning continues to play a fundamental role for the sustainable organization and development of the towns. The analysis and evaluation of the potentialities and limitations of the urban physical environment is essential to the process of planning, organization and control of land use. Therefore, Geotechnical Cartography plays a very important role in facing the problems inherent in the action of man on the physical and natural environment. But, despite the considerable development of the National Geotechnical Cartography, it is still necessary to make progress in its application to the urban environment and planning, as well as a better adaptation to the economic and instrumental reality of the great majority of Brazilian municipalities, especially those of medium and small sizes. The present work intends to contribute with the development of tools to support the planning of towns sustainable growth through the structuring of a progressive geotechnical mapping procedure which incorporates the city growth analysis. Applied to the town of Pelotas / RS, the method uses pre-existing data and had the objective to produce maps of susceptibility and urbanization suitability map applicable to planning Starting from the inventory stage and going through the preparation and generation of data, the mapping was developed through the general and semi-detailled stages of the progressive method. In this case the attributes of the physical medium, represented by of Information Plans on Geographic Information System, were combined through multivariate analysis. The mapping of the urban voids and the modeling and simulation of the city growth allowed the concentration of the final stages of mapping, and the geotechnical analysis, only to the areas of future urbanization, reducing efforts and optimizing the whole process. The results indicate the validity of the method and its capacity to contribute in the regulation of land use in the study area, with potential to use in other situations. By comparing the urban legislation and the spatial growth of the town with the mapping products it was observed that the lack of geotechnical information was determinant in the past occupation of areas of very low and low aptitude for urbanization in Pelotas. This reinforces the importance of utilizing geological-geotechnical information in urban planning and management in Brazil.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Diques de basaltos toleíticos de baixo-TiO2 ocorrem na porção oriental do Enxame de Diques da Serra do Mar, na Região dos Lagos, entre Niterói e Búzios. Eles têm direções, preferencialmente, NE-SW, subordinadamente, NNE-SSW e mais raramente, NW-SE, e formas intrusivas variáveis. Os basaltos são holocristalinos a hipocristalinos, inequigranulares a equigranulares, intergranulares e intersertais. Eles são constituídos essencialmente de plagioclásio, augita e/ou pigeonita, com olivina corroída, minerais opacos e apatita como minerais acessórios e biotita, bowlingita, idingisita, uralita e saussurita como minerais secundários. A assembléia de fenocristais destas rochas foi estimada em 15% de olivina, 40% de augita e 45% de plagioclásio. Os rochas inserem-se numa série basáltica subalcalina de afinidade toleítica de baixo-TiO2 pouco expandida (MgO= 8,13-5,91%peso), não tendo sido encontradas amostras representativas de líquidos basálticos primários. Esta suíte predominante foi denominada Suíte Costa Azul. No entanto, os dados litogeoquímicos apontam para a existência de mais que uma suíte de baixo-TiO2 na área de estudo que, segundo modelos de fusão parcial em equilíbrio modal, poderiam ter sido geradas por diferentes quantidades de fusão a partir de uma mesma fonte com granada residual. Em termos regionais, a suíte Costa Azul pode ser relacionada com a Suíte Esmeralda que ocorre na subprovíncia Sul de Paraná-Etendeka, muito embora abrangendo um espectro mais amplo de razões Ti/Y. As rochas da suíte Costa Azul evoluíram por 42% de cristalização fracionada envolvendo uma assembléia de fenocristais composta por 15% de olivina, 40% de augita e 45% de plagioclásio, sem mudança de assembléia fracionante. Misturas de componentes mantélicos empobrecidos (mínimo de 72% de D-MORB) e enriquecidos (máximo de 28% de manto litosférico subcontinental) estão associadas à petrogênese desta suíte. Misturas entre componentes do tipo pluma e litosféricos não conseguem explicar as composições parentais da suíte. Os modelos petrogenéticos permitiram a proposição de um modelo geodinâmico envolvendo delaminação do manto litosférico subcontinental englobado por células convectivas ascendentes do manto sublifosférico subjacente em níveis astenosféricos pouco profundos durante um estágio avançado de rifteamento do supercontinente Gondwana. / Low-TiO2, tholeiitic basalt dykes occur eastwards the Serra do Mar Dyke Swarm within the Região dos Lagos from Niterói up to Búzios city. The dykes strike preferentially NE-SW bearing variable intrusive structures. The basalts are holo- to hypocrystaline, equigranular to inequigranular rocks with mostly intergranular and intersertal textures. They are composed mostly by plagioclase, augite and/or pigeonite and have corroded olivine, opaque minerals and apatite as accessory phases. Secondary mineralas are represented by biotite, bowlingite, iddingisite, uralite and saussurite. The phenocrysts assemblage comprise 15% olivine, 40% augite and 45% plagioclase. The rocks comprise a low-TiO2, subalkaline, tholeiitic basaltic suite hereafter called the Costa Azul suite. Nevertheless, lithogeochemical data point to the existence of more than one low-TiO2 suite in the study area. Geochemical modelling has shown that these suites can be related by different degrees of partial melting from a similar mantle source with residual garnet. The Costa Azul suite can be related with the Esmeralda low-TiO2 basaltic suite within the Paraná-Etendeka CFB province due south Brazil although comprising a wider Ti/Y ratio range. The rocks of the Costa Azul suite evolved by 42% of fractional crystallisation involving a phenocryst assemblage with 15% de olivine, 40% augite and 45% plagioclase. Binary mixing modelling point to at least 72% of a D-MORB component and 28% of a subcontinental lithospheric mantle (SCLM) component in the petrogeneses of the Costa Azul basalts. Models involving mixing between plume-like asthenospheric and SCLM components cannot explain the geochemistry of parental liquids in the Costa Azul suite. A geodynamic model involving continental lithosphere delamination and entrainment by ascending convection cells from the underlying asthenospheric depleted mantle during an advanced stage of Gondwana rifting is depicted on the basis of the petrogenetic models proposed for the Costa Azul suite.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Diques de basaltos toleíticos de baixo-TiO2 ocorrem na porção oriental do Enxame de Diques da Serra do Mar, na Região dos Lagos, entre Niterói e Búzios. Eles têm direções, preferencialmente, NE-SW, subordinadamente, NNE-SSW e mais raramente, NW-SE, e formas intrusivas variáveis. Os basaltos são holocristalinos a hipocristalinos, inequigranulares a equigranulares, intergranulares e intersertais. Eles são constituídos essencialmente de plagioclásio, augita e/ou pigeonita, com olivina corroída, minerais opacos e apatita como minerais acessórios e biotita, bowlingita, idingisita, uralita e saussurita como minerais secundários. A assembléia de fenocristais destas rochas foi estimada em 15% de olivina, 40% de augita e 45% de plagioclásio. Os rochas inserem-se numa série basáltica subalcalina de afinidade toleítica de baixo-TiO2 pouco expandida (MgO= 8,13-5,91%peso), não tendo sido encontradas amostras representativas de líquidos basálticos primários. Esta suíte predominante foi denominada Suíte Costa Azul. No entanto, os dados litogeoquímicos apontam para a existência de mais que uma suíte de baixo-TiO2 na área de estudo que, segundo modelos de fusão parcial em equilíbrio modal, poderiam ter sido geradas por diferentes quantidades de fusão a partir de uma mesma fonte com granada residual. Em termos regionais, a suíte Costa Azul pode ser relacionada com a Suíte Esmeralda que ocorre na subprovíncia Sul de Paraná-Etendeka, muito embora abrangendo um espectro mais amplo de razões Ti/Y. As rochas da suíte Costa Azul evoluíram por 42% de cristalização fracionada envolvendo uma assembléia de fenocristais composta por 15% de olivina, 40% de augita e 45% de plagioclásio, sem mudança de assembléia fracionante. Misturas de componentes mantélicos empobrecidos (mínimo de 72% de D-MORB) e enriquecidos (máximo de 28% de manto litosférico subcontinental) estão associadas à petrogênese desta suíte. Misturas entre componentes do tipo pluma e litosféricos não conseguem explicar as composições parentais da suíte. Os modelos petrogenéticos permitiram a proposição de um modelo geodinâmico envolvendo delaminação do manto litosférico subcontinental englobado por células convectivas ascendentes do manto sublifosférico subjacente em níveis astenosféricos pouco profundos durante um estágio avançado de rifteamento do supercontinente Gondwana. / Low-TiO2, tholeiitic basalt dykes occur eastwards the Serra do Mar Dyke Swarm within the Região dos Lagos from Niterói up to Búzios city. The dykes strike preferentially NE-SW bearing variable intrusive structures. The basalts are holo- to hypocrystaline, equigranular to inequigranular rocks with mostly intergranular and intersertal textures. They are composed mostly by plagioclase, augite and/or pigeonite and have corroded olivine, opaque minerals and apatite as accessory phases. Secondary mineralas are represented by biotite, bowlingite, iddingisite, uralite and saussurite. The phenocrysts assemblage comprise 15% olivine, 40% augite and 45% plagioclase. The rocks comprise a low-TiO2, subalkaline, tholeiitic basaltic suite hereafter called the Costa Azul suite. Nevertheless, lithogeochemical data point to the existence of more than one low-TiO2 suite in the study area. Geochemical modelling has shown that these suites can be related by different degrees of partial melting from a similar mantle source with residual garnet. The Costa Azul suite can be related with the Esmeralda low-TiO2 basaltic suite within the Paraná-Etendeka CFB province due south Brazil although comprising a wider Ti/Y ratio range. The rocks of the Costa Azul suite evolved by 42% of fractional crystallisation involving a phenocryst assemblage with 15% de olivine, 40% augite and 45% plagioclase. Binary mixing modelling point to at least 72% of a D-MORB component and 28% of a subcontinental lithospheric mantle (SCLM) component in the petrogeneses of the Costa Azul basalts. Models involving mixing between plume-like asthenospheric and SCLM components cannot explain the geochemistry of parental liquids in the Costa Azul suite. A geodynamic model involving continental lithosphere delamination and entrainment by ascending convection cells from the underlying asthenospheric depleted mantle during an advanced stage of Gondwana rifting is depicted on the basis of the petrogenetic models proposed for the Costa Azul suite.

O crescimento acelerado das cidades associado à ausência, inadequação ou ineficácia do planejamento urbano, no Brasil, tem acarretado o desequilíbrio dos sistemas ambientais e a imposição de riscos a parcelas significativas da população. Muito embora as numerosas críticas aos modelos de planejamento aplicados no País, o urbanismo continua desempenhando um papel fundamental na organização e desenvolvimento das cidades. A leitura e avaliação das potencialidades e limitações do meio físico urbano são essenciais ao processo de planejamento, organização e controle do uso do solo; sendo assim, a cartografia geotécnica desempenha um papel de relevância no enfrentamento dos problemas inerentes à ação do homem sobre o meio físico. Mas, apesar do considerável desenvolvimento da cartografia geotécnica nacional, ainda são necessários avanços no que se refere à sua aplicação ao ambiente urbano e ao planejamento, bem como uma melhor adequação à realidade econômica e instrumental da maioria dos municípios brasileiros, em especial os de médio e pequeno porte. O presente trabalho pretende contribuir com o desenvolvimento de instrumentos de auxílio ao planejamento do crescimento sustentável da cidade, através da estruturação de um procedimento progressivo de mapeamento geotécnico que incorpora a análise do crescimento da cidade como etapa de seu desenvolvimento. Aplicado ao município de Pelotas/RS, o método tem por base o uso de dados pré-existentes e objetivou a produção de mapas de suscetibilidade e da carta de aptidão à urbanização, aplicáveis ao planejamento territorial urbano Partindo da etapa de inventário e passando pela fase de preparação e geração de dados, o mapeamento foi desenvolvido através da etapa geral e de semi-detalhe do método progressivo, nas quais os atributos do meio físico foram cruzados por meio de análise multivariada e uso de Sistema de Informações Geográficas. O mapeamento dos vazios urbanos e a modelagem e simulação do crescimento da cidade permitiram o direcionamento das etapas finais de mapeamento e a redução das análises geotécnicas às áreas territoriais de urbanização futura, reduzindo esforços e otimizando o processo como um todo. A aplicação do método produziu um grande número de informações, mapas, cartas e caracterizações do meio físico, com larga possibilidade de utilização no planejamento do crescimento futuro da cidade e na implantação de medidas corretivas aos problemas e conflitos decorrentes do processo de urbanização passada. Os resultados alcançados indicam tanto a validade da metodologia para o estudo em particular, quanto seu potencial de utilização, parcial ou total, a outras realidades fisiográficas. Através da contraposição da legislação urbanística, do processo de crescimento da cidade e dos produtos do mapeamento, foi possível concluir que a inexistência da informação geológico-geotécnica foi determinante na ocupação de áreas de muito baixa e baixa aptidão à urbanização na zona urbana do município de Pelotas. Tal constatação reforça, assim, a importância do uso da informação geológicogeotécnica no planejamento e na gestão urbana nacional. / The accelerated growth of towns associated with the absence, inadequacy or low efficiency of urban planning in Brazil has caused changes of environmental systems and the imposition of risks to significant portions of the population. Despite the numerous criticisms of the planning models applied in the country, urban planning continues to play a fundamental role for the sustainable organization and development of the towns. The analysis and evaluation of the potentialities and limitations of the urban physical environment is essential to the process of planning, organization and control of land use. Therefore, Geotechnical Cartography plays a very important role in facing the problems inherent in the action of man on the physical and natural environment. But, despite the considerable development of the National Geotechnical Cartography, it is still necessary to make progress in its application to the urban environment and planning, as well as a better adaptation to the economic and instrumental reality of the great majority of Brazilian municipalities, especially those of medium and small sizes. The present work intends to contribute with the development of tools to support the planning of towns sustainable growth through the structuring of a progressive geotechnical mapping procedure which incorporates the city growth analysis. Applied to the town of Pelotas / RS, the method uses pre-existing data and had the objective to produce maps of susceptibility and urbanization suitability map applicable to planning Starting from the inventory stage and going through the preparation and generation of data, the mapping was developed through the general and semi-detailled stages of the progressive method. In this case the attributes of the physical medium, represented by of Information Plans on Geographic Information System, were combined through multivariate analysis. The mapping of the urban voids and the modeling and simulation of the city growth allowed the concentration of the final stages of mapping, and the geotechnical analysis, only to the areas of future urbanization, reducing efforts and optimizing the whole process. The results indicate the validity of the method and its capacity to contribute in the regulation of land use in the study area, with potential to use in other situations. By comparing the urban legislation and the spatial growth of the town with the mapping products it was observed that the lack of geotechnical information was determinant in the past occupation of areas of very low and low aptitude for urbanization in Pelotas. This reinforces the importance of utilizing geological-geotechnical information in urban planning and management in Brazil.

L’évolution géodynamique et physiographique de l’espace Méditerranéen, en particulier au sein des bassins bordiers de Valence et Adriatique, sont intimement liées à l’héritage anté-Néogène. L’identification de la segmentation des bassins et leur implication dans l’histoire tectonique et environnementale au Néogène, en particulier lors de la crise d’érosion et de salinité Messinienne (MESC - 5.96-5.32 Ma), reste cependant méconnus et font l’objet de ce travail de recherche. Afin de les mettre en lumière, nous proposons une vision complète du remplissage sédimentaire Néogène des deux bassins, sur la base d’une compilation de profils sismiques et de forages industriels. Nos résultats illustrent une segmentation du domaine Valence-Provençal en trois sousbassins d’âges, de subsidences et de nature crustales différentes. Un nouveau scénario cinématique est proposé à l’échelle des bassins Valencien et Algérien. Cette segmentation met en lumière lors de la MESC un système complet de vallées incisées fluviatiles long de plus de 270 km. Associé aux différents cortèges sédimentaires, un nouveau regard est jeté sur l’événement Messinien et le paradoxe d’ouverture du bassin de l’Ebre. Au sein du domaine Adria, l’héritage Mésozoïque contrôle en premier lieu les environnements néogènes, où deux dépocentres majeurs se distinguent de part et autre du seuil composite Apulien-Gargano-Pelagosa. La propagation des fronts de déformations Albanide et Apennin se surimpose à cet héritage et contrôle la sédimentation et les mouvements verticaux de ces dépocentres La période Messinienne est alors perçue comme une phase de réorganisation tectonique majeure, cette dernière se surimposant à la MESC. / The geodynamic evolution of the Mediterranean area, especially in the Valencia and Adriatic basins, is strongly influenced by its ante-Neogene history. The localization of existing thresholds at that time, and their impact on the following tectono- sedimentary evolutions still remain largely unknown. In this work, we will try to reconstruct this evolution and better understand the part of these thresholds, in particular during the Messinian Erosional and Salinity Crisis (MESC, 5.96-5.32 Ma). We provide here a complete view of the Neogene sedimentary infilling for the both Valencia and Adriatic basins thanks to a compilation of seismic profiles correlated to industrial boreholes.Our results allow us to individualize the Valence-Provençal domain into three subbasins whose ages, subsidence and crustal nature differ. A new kinematic and geodynamic scenario for the Valencia and Neogene Algerian basins is proposed here. This segmentation provides also information about MESC. We highlight a fully incised-valley system whose length reaches more than 270 km, the latter associated with the development of several system tracts. Overall, these interpretations lets us look the Ebro basin connection paradox from a different angle.The Mesozoic Apulian-Gargano-Pelagosa composite threshold mainly control the Neogene sedimentation in the Adria domain and distinguishes two main depocenters. The propagating of the Albanid and Apennine deformation fronts control also the evolution of vertical movements and the sedimentation. Our results imply that the Messinian period corresponds to a major tectonic and/or kinematic reorganization phase within which the MSC is a superimposed event.

Le Cénozoïque est marqué par une instabilité climatique et l’accélération des surrections continentales. Ces phénomènes engendrent une augmentation de la production sédimentaire, transférée par les fleuves vers le domaine marin profond. Les façades nord et ouest de l’océan Indien voient se mettre en place quatre des plus grands systèmes sédimentaires au monde : le Gange-Brahmapoutre, l’Indus, le Zambèze et le système tanzanien. Ce travail vise à comprendre les forçages agissant sur la sédimentation et l’architecture de deux des principaux systèmes turbiditiques de l’océan Indien (système tanzanien et du Gange-Brahmapoutre), pour ensuite les comparer avec leurs plus proches voisins (respectivement le Zambèze et l’Indus). Nos principaux résultats, basés sur une approche multiproxy dans les deux zones, mettent en évidence plusieurs points : (1) l’évolution tectono-sédimentaire de la marge tanzanienne au cours du Cénozoïque a mené au développement d’un système turbiditique majeur et atypique, dont la morphologie moderne atteste de l’importance de l’activité tectonique sur sa construction ; (2) le système du Gange-Brahmapoutre enregistre une activité sédimentaire polyphasée, en lien principalement avec les variations du niveau marin. Ce système est capable d’enregistrer les variations de nombreux forçages, influençant à la fois les bassins versants et le domaine marin. Le fonctionnement sédimentaire et l’architecture des systèmes turbiditiques ont révélé une grande diversité selon le contexte géodynamique et physiographique des façades étudiées. La nécessité d’intégrer l’ensemble des forçages (agissant depuis le bassin versant jusque dans le domaine marin profond) dans l’étude de l’activité sédimentaire d’un système turbiditique apparait essentielle de nos jours. / Cenozoic is marked by climatic instability and accelerating continental uplifts. Increasing sediment yield is generated, buffered and transferred by river to the deep sea. Four of the major turbidite systems in the world are located on the northern and the western margins of the Indian Ocean: the Ganges-Brahmaputra, the Indus, the Zambezi and the Tanzanian systems. This work aims to understand forcings affecting sedimentation and morphology of two main turbidite systems (Tanzanian system and Ganges-Brahmaputra system) and results have been compared with their nearest neighbors (respectively Zambezi and Indus). Based on a multiproxies approach in both area, our main results are as follows: (1) during Cenozoic, tectono-sedimentary evolution of the Tanzania margin led to the development of an atypical turbidite system wherein morphology attest of a strong structural control; (2) the Ganges-Brahmaputra system has a sedimentary activity mainly forced by sea level variations. This turbidite system records variations in many forcings impacting sedimentation from the catchment to the deep sea. Turbidite system activity and architecture revealed a strong variability mainly linked to the geodynamic and physiographic context of each studied margin. It appears necessary to integrate all forcings (affecting both the catchment and the deep sea) in the study and the understanding of sedimentary activity in a turbidite system.

The thesis deals with processing of epoch-wise GNSS measurements from local geodynamic network Sněžník. Its aim is to evaluate the geodynamics in the area of Králický Sněžník Massif and to assess the capabilities of epoch-wise GNSS measurements to detect the geodynamic movements. Within the thesis the comprehensive processing of all the GNSS measurements observed between years 1997 and 2011 is realized using the reprocessed products of first IGS reprocessing Repro1. Bernese GPS software version 5.0 is used for all the processing.

Le bassin Ionien, en Méditerranée centrale, abrite une zone de subduction à vergence Nord-Ouest où la plaque Afrique plonge sous les blocs Calabro-Péloritain au Nord-Est de la Sicile. Cette subduction résulte de la lente convergence entre les plaques tectoniques Afrique et Eurasiatique. Bien que de nombreuses campagnes d’exploration scientifique ont été menées dans cette zone particulière, plusieurs questions géodynamiques restent débattues. Tout d’abord la croûte pavant le bassin Ionien pourrait être soit de nature continentale amincie et représenter une extension de la plaque Afrique, soit océanique (Néo-Téthys) faisant de ce bassin l’un des plus anciens domaines océaniques au monde. L’escarpement de Malte représente un vestige de l’ouverture du bassin, mais les mécanismes de rifting et notamment la géométrie d’ouverture du bassin restent débattus. Cette subduction est en retrait vers le Sud-Est depuis les derniers 35 Ma, mais est aujourd’hui confinée à l’étroit bassin Ionien. Afin d’accommoder ce retrait de la plaque plongeante dans le bassin, une grande faille de déchirure lithosphérique de bord de subduction (STEP fault en anglais pour « subduction Transform Edge Propagator ») doit se propager le long de la marge Est-Sicilienne. Cependant, sa position en surface reste difficile à déterminer dans l’épais prisme d’accrétion recouvrant le bassin. Ces questions ont été explorées par modélisation des données de sismique grand angle de la campagne DIONYSUS (Octobre 2014, R/V Meteor) le long de deux profils perpendiculaires à la marge Est-Sicilienne. Des modélisations gravimétriques en 3D ont aussi été réalisées dans le but de localiser la plaque plongeante en profondeur sous les blocs Calabro-Péloritains. La sismicité des trois structures majeures du bassin : l’escarpement de Malte, l’AFS (Alfeo Fault System), et l’IFS (Ionian Fault System) a permis d’étudier leurs activités à l’actuel. Les résultats obtenus permettent d’observer une croûte océanique au fond du bassin. La structure profonde de l’escarpement de Malte est observée comme une zone d’amincissement crustal abrupt, ce qui est caractéristique des marges transformantes. Un profond bassin sédimentaire asymétrique (11 km) est observé au Sud du détroit de Messine. Il s’est probablement ouvert récemment entre les blocs continentaux Péloritain et Calabre. Dans le lobe Ouest du prisme d’accrétion Calabrais, le modèle de vitesse permet d’observer l’indentation du prisme clastique interne dans le prisme évaporitique externe. Des modélisations analogiques utilisant sable et silicone ont permis de démontrer la récente activité de ce lobe. L’interprétation des modèles de vitesse permet de localiser la faille STEP le long de l’AFS sur les deux profils. / In the Ionian Sea (central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust of the subducting plate remains debated and could represent the last remnants of the Neo-Tethys ocean. The origin of the Ionian basin is also under discussion, especially concerning the rifting mechanisms as the Malta Escarpment could represent a remnant of this opening. This subduction retreats toward the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian basin. A major lateral slab tear fault is required to accommodate the slab rollback.This fault is thought to propagate along the eastern Sicily margin but its precise location remains controversial.This PhD project focussed on the deep sedimentary and crustal structures of the eastern Sicily margin and the Malta Escarpment (ME). Two two-dimensional P wave velocity models were modelled by forward Modelling of wide-angle seismic data, acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014.A 3D gravity model of the region was also performed to constrain the depth of the subducting slab bellow the Calabro-Peloritan backstops. The seismicity of the three structures identified in the velocity models (ME, Alfeo fault System, Ionian Fault System) permits to study their recent activity. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment, which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened between the Calabrian and Peloritan continental terranes. In the western lobe of the Calabrian accretionary prism, the southern velocity model allows to observe the indentation of the internal clastic wedge into the external evaporitic wedge, thus showing the recent activity of this lobe. The interpretation of the velocity models suggests that the major STEP fault is located east of the Malta Escarpment, along the Alfeo Fault System.

La compréhension des processus et des modalités de l’inversion des systèmes extensifs et plus particulièrement les domaines de marges amincies, dans les chaines de collision est un enjeu majeur. La chaîne intracontinentale des Pyrénées constitue un exemple d’inversion de marges passives hyper-amincies, associées à un métamorphisme HT-BP et intégrées dans le prisme orogénique. La première partie de cette étude est centrée sur l’étude de la répartition du métamorphisme HT-BP associé à la phase de rifting et de l’exhumation du manteau lithosphérique. L’apport des données de TRSCM a permis, dans un premier temps, de définir l’enveloppe de la ZIM caractérisée par des températures comprises entre 400 et 630°C à l’échelle de l’ensemble de la chaîne et de montrer qu’il n’existe pas de gradient significatif des températures maximales à cette échelle. Dans un second temps, cette étude a permis de mettre en évidence des sauts de température importants au travers de failles majeures et de distinguer des gradients de températures latéraux à l’échelle des différents bassins constituant la ZIM, en particulier dans l’ouest de la chaîne sur l’exemple de la Nappe de Marbres. Cette partie de l’étude montre également l’importance d’une tectonique salifère antérieure au métamorphisme de HT-BP. La seconde partie de cette étude, concernant la structure de la ZIM met en évidence trois phases de déformation, associées à l’orogenèse pyrénéenne ainsi que le rôle du niveau de décollement des évaporites du Trias supérieur dans l’allochtonie généralisée de la ZIM. De plus, les failles majeures observées dans la ZNP, montrent un mouvement inverse avec une composante décrochante sénestre. L’interprétation de l’ensemble de ces résultats suggère que la ZIM et la ZNP ne forme qu’une seule unité découplée du socle varisque au niveau du Trias supérieur et déplacée par des chevauchements plats issus de l’héritage extensif, lors du début de la convergence. Le mode de déformation est alors de type thin-skinned, puis devient, lors de la collision des deux paléomarges, de type thick-skinned, avec le développement de faille majeures associées à l’exhumation des blocs de socle (Massifs Nord-Pyrénéens) qui ont découpé l’ensemble de la ZIM. / The understanding of the processes and scenarios of the inversion of extensional systems, and more specifically of hyper-extended margins, in collision thrust belts is a major issue. The intracontinental belt of the Pyrenees is an example of inversion of hyper-extended margins, associated with a HT-LP metamorphism and then integrated within the orogenic wedge. The first part of this study is focused on the distribution of the HT-LP metamorphism associated with rifting and the exhumation of lithospheric mantle. A new set of TRSCM data allows the recognition of the geometry of the IMZ, characterized with temperature ranging from 400 to 630°C and shows the absence of a regional gradient at this scale. This study then shows significant temperature gaps across major faults and distinguishes lateral temperature gradients at the scale of the different basins constituting the IMZ, especially in the westernmost part of the belt, in the Nappe des Marbres Basin. This part of the study moreover shows the importance of a salt tectonics prior to the HT-LP metamorphism. The second part shows the existence of three main tectonics phases during the Pyrenean orogeny and the role played by the Late Triassic evaporites as a decollement level in the generalized allochthony of the IMZ. A left-lateral component along the main faults within and along the boundaries of the North Pyrenean Zone (ZNP) is also shown. The interpretation of these observations is that the IMZ and ZNP form a single tectonic unit, decoupled from the Variscan basement by the decollement in the Late Triassic deposits and displaced above shallow-dipping thrust faults inherited from the rifting episode, during the first stages of the convergence. Deformation mode is then thin-skinned and becomes thick-skinned when the two paleomargins collide, with the development of major steeper faults linked with the exhumation of basement blocks (North Pyrenean Massifs) that dissected the IMZ.