Metal-Organic Frameworks (MOFs) are highly porous materials built from inorganic nodes joined by organic linkers forming extended crystalline networks. One of the distinguishing features of metal-organic frameworks is the ability to adaptively change their crystal structure in response to external stimuli with significant porosity switching. Such structural switchability of MOFs offers new opportunities in gas separation, selective recognition, sensing, and energy storage. However, there are still open questions in understanding factors affecting switchability. The electronic structure of the metal in the building blocks, host-guest interactions, but also particle size, morphology, surface, desolvation conditions are involved into the responsiveness of the system. One of the representative of switchable metal-organic frameworks is pillared-layer DUT-8 (M2(2,6-ndc)2(dabco), M = Ni, Co, Cu, Zn, 2,6-ndc = 2,6-naphthalenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane). Depending on the metal node and particle size, it is possible to synthesize either switchable or rigid materials differing in physisorption isotherm profiles. In order to understand switching behaviour of DUT-8, the important parameters influencing structural switchability are addressed in my work. For this purpose, the impact of crystal size and morphology, as well as crystal surface on adsorption-induced structural transformations of DUT-8(Ni) were investigated. DUT-8(Ni) shows reversible structural transition between open (op) and closed pore phase (cp) upon adsorption/removal of guest molecules. To understand which particular crystal surfaces dominate the phenomena observed, crystals similar in size and differing in morphology were involved in a systematic study. The analysis of the data shows that the width of the rods (corresponding to the crystallographic directions along the layer) represents a critical parameter governing the dynamic properties upon adsorption of nitrogen at 77 K. This observation is related to the anisotropy of the channel-like pore system and the nucleation mechanism of the solid-solid phase transition triggered by gas adsorption. To investigate the influence of external surface on adsorption-induced switchability, DUT-8(Ni) samples were exposed to different treatment techniques. By means of analytical methods, it was revealed that the surface of samples was modified leading to a significant increase of the gate-opening pressure, reflecting the increase of activation barrier for phase switching form cp to op upon adsorption of nitrogen at 77 K. Furthermore, the properties of DUT-8(Zn) were studied precisely, focusing on the variation of particle size and morphology, host-guest interactions, desolvation conditions, selectivity and thermoresponsivity. Depending on the synthesis conditions, DUT-8(Zn) can be synthesised in macro-sized regime (150 µm) and micron-sized regime (0.5 µm). The solvent removal process (pore desolvation stress contracting the framework) significantly controls the cp/op ratio after desolvation and, subsequently, the adsorption induced switchability characteristics of the system. Among the applied desolvation techniques, the solvent exchange with subsequent heating causes phase transition from open (op) to closed pore phase (cp). After desolvation, the dense cp phase of DUT-8(Zn) shows no adsorption-induced reopening and therefore is non-porous for N2 at 77 K and CO2 at 195 K. However, polar molecules with a higher adsorption enthalpy, such as chloromethane at 249 K and dichloromethane (DCM) at 298 K can reopen the macro-sized crystals upon adsorption, while micron-sized crystals retain the cp phase. For macro-sized particles (160 µm), the outer surface energy is negligible and only the type of metal (Zn, Co, Ni) controls the DCM-induced gate opening pressure. The node hinge stiffness increases from Zn to Ni as confirmed by DFT calculations, X-ray crystal structural analysis, and low frequency Raman spectroscopy. This softer Zn-based node hinges and overall increased stabilization of cp vs. op phase shift the critical particle size at which switchability starts to become suppressed to even lower values. Hence, the three factors affecting switchability (energetics of the empty host, (Eop–Ecp) (i), particle size (ii), and desolvation stress (iii)) appear to be of the same order of magnitude and should be considered collectively, not individually. Crystal downsizing (0.5 µm) facilitates the responsivity of DUT-8(Zn) towards different guest molecules, not opening for macro-sized crystals. Among investigated adsorptives, the alcohols are in the center of attention due to ability to induce so called shape-memory effect in micron-sized crystals. The adsorption of alcohols stimulates the change of initial shape of pores (cp) into a temporary shape (op) which is maintained even after desorption. To brighten the crystal size range and to study the dependence of gate opening pressure from crystal size and morphology, differently shaped crystals in micron-sized regime were produced by face-selective coordination modulation. Morphology modification allowed to determine the critical parameter controlling switchable transformations in DUT-8(Zn). Thus, the crystal size engineering and morphology modification provide an opportunity not only to control the structural dynamics of MOFs, but also to tailor responsivity towards guest molecules, influencing the selective adsorption behaviour.

Heard Island is a remote Australian territory which lies in the South-middle sector of the Indian Ocean.The island lies in the central province of the Kerguelen Plateau. On the north-western face of the islandlies the Laurens Peninsula, where modern volcanism has been periodic since approximately 10 ka, butno eruption has been recorded. The main volcanic feature of the peninsula is Mt Dixon of which noactivity has been observed but it is thought to have erupted within the past few hundred years. This thesis applied the crystal size distribution method to three thin sections from the LaurensPeninsula. The samples were collected from a phonolite from Jacka valley, a teprhiphonolite from thebase of the Red Island cone, and a tephrite east of Cape Cartwright. Crystal dimensions were calculatedusing ImageJ Fiji, these dimensions were corrected for 3D dimensions using CSDslice, and the datawas plotted using CSDcorrections. Microcrysts were traced using backscattered electron (BSE) images,and high resolutions scans of the thin section were used to trace phenocrysts. The results of the crystalsize distributions show concave-up shapes in all plots with steep slopes for smaller crystals, followedby shallow slopes for larger crystals. This suggests binary magma mixing by replenishment occurred inthe magmas associated with all three samples. The different slopes suggest two separate crystallisationconditions: Phenocrysts crystalized slowly in the chamber and microcrysts crystallized relativelyquickly during or after eruption. Textural differences in the three samples suggest that the tephrite hadthe longest residence time and underwent the most replenishment events, followed by thetephriphonolite and lastly the phonolite. Finally, since replenishment is the mechanism of mixingbeneath the Laurens Peninsula, then volcanism might still be active, and the chambers could currentlybe replenishing, which could trigger an eruption. / Heard Island är ett avlägset australiensiskt territorium som ligger i den södra delen av den Indiskaoceanen. Ön ligger i den centrala provinsen på Kerguelenplatån. På den nordvästra sidan av ön liggerLaurens-halvön, där modern vulkanism daterar sig till cirka 10 ka. Den främsta vulkaniska strukturenpå halvön är Mt Dixon där ingen aktivitet har registrerats, men som tros ha haft ett utbrott under desenaste hundra åren. Denna avhandling tillämpade metoden för kristallstorleksfördelning på tre tunnslipar frånLaurenshalvön. Proverna samlades in från en fonolit från Jacka valley, en tefrifonolit från basen av RedIsland cone och en tefrit öster om Cape Cartwright. Kristalldimensioner beräknades med ImageJ Fiji,dessa dimensioner korrigerades för 3D-dimensioner med CSDslice, och datat plottades medCSDcorrections. Mikrokristaller spårades med hjälp av backscattered electron images (BSE) ochhögupplösta skanningar av tunnslipen användes för att spåra fenokryster. Resultaten avkristallstorleksfördelningarna föreslog binär magmablandning via påfyllning i alla tre proverna. Dessavisade konkava former i alla plotter med branta sluttningar för mindre kristaller, följt av plattaresluttningar för större kristaller. De olika lutningarna på kurvorna föreslog två separatakristallisationsförhållanden: fenokryster kristalliserade långsamt i kammaren, och mikrokristallerkristalliserade relativt snabbt under eller efter utbrottet. Texturella skillnader i de tre proverna antyddeatt tefriten hade den längsta residenstiden och genomgick flest påfyllningshändelser, följt avtefrifonoliten och slutligen fonoliten. Slutligen, om påfyllning var mekanismen för att blandas underLaurenshalvön, så kan vulkanismen fortfarande vara aktiv, men för närvarande i ettpåfyllningsuppehåll.

The Limeira Intrusion is an occurrence related to the Mesozoic continental flood basalts of Paraná Magmatic Province, cropping out at the eastern São Paulo state. It is made up of basic- intermediate rocks with a great diversity of structures, textures, and modal compositions, related to the specific evolutionary process in a magma chamber. 2D forward modeling of magnetometric data, based on available aerial and newly obtained ground data integrated with in situ rock magnetic susceptibility measurements, were used to establish its geometry. The results, even considering intrinsic drawbacks of magnetometric theoretical models, are compatible with the geologic-based presumed intrusion geometry. In addition, the stratigraphic analysis of compositional and textural variations, coupled with the structural and geometric features, allowed the interpretation of its emplacement mechanism and thermal evolution. Quantitative textural analysis through crystal size distribution (CSD) of plagioclase crystals, the spatial distribution pattern of structures, microtextures, granulation, and rock-types, evidenced the internal heterogeneities of this occurrence. An approximately 110 m top-to-floor exposure section reveals that its internal heterogeneity was caused by non-instantaneous successive emplacement of three different magma injections. The textural analysis also reveals fine-grained crystals formed under different cooling paths, present in medium- to coarse- grained rocks within the intrusion, next to sharp contacts between different rock compositions. The contacts between different rocks are characterized by hybridization textures and by significant amounts of plumose granophyre-type and plumose plagioclase. The time lapse between consecutive pulses is responsible for a stepwise cooling-path, preservation of hybridization textures, and the development of almost rigid surfaces providing crystals alignment during magma flow. High-resolution Sr-isotopy data demonstrates a complex assembly history, possibly involving filter pressing of residual liquids, and pre-existent crystals before magma installation in coarse-grained rocks. It is also possible to recognize fewer amounts of country-rocks assimilation, which decreases towards the intrusion\'s core and can be associated with magma migration due to filter pressing processes. In the feeder zone, the evolution of emplacement was marked by an almost continuous decrease in wall-rock assimilation by the consecutive magma batches. / A intrusão de Limeira é uma ocorrência associada aos basaltos continentais Mesozoicos da Província Magmática do Paraná, aflorando na região leste do estado de São Paulo. Esta intrusão é composta por rochas básico-intermediárias que ocorrem com grande diversidade de estruturas, texturas e composições modais, relacionados aos mecanismos evolutivos específicos desta câmara. A modelagem magnetométrica bidimensional, baseado em aerolevantamentos disponíveis e dados recentes obtidos em campo e integrados às medidas de suscetibilidade magnética em rocha, foram utilizados para estabelecer sua geometria. Os resultados, mesmo considerando as desvantagens intrínsecas teóricas do método, são compatíveis com o modelo geológico presumido para esta intrusão. Adicionalmente, a análise das variações estratigráficas de composição e texturas, associados aos parâmetros estruturais e geológicos, permitiram a interpretação dos mecanismos de colocação e evolução térmica desta intrusão. Análises texturais quantitativas através da análise de distribuição de tamanho de cristais (DTC), a distribuição espacial de padrões estruturais, microtexturas, granulação e litotipos, evidenciam a heterogeneidade interna desta ocorrência. A seção de aproximadamente 110 metros de topo- a-base revela que sua heterogeneidade interna foi causada pela injeção sucessiva de pelo menos três pulsos magmáticos. Através da análise textural foram reconhecidos cristais de plagioclásio de granulação muito fina a fina presentes em rochas de granulação média a grossa, formados em diferentes razões de resfriamento e próximo ao contato abrupto entre rochas de diferentes composições. Estes contatos caracterizam zonas onde são reconhecidas texturas híbridas e são marcados pela presença e abundância de intercrescimentos granofíricos do tipo plumoso e plagioclásios plumosos. O espaço de tempo entre pulsos magmáticos consecutivos é responsável pela evolução térmica em etapas nesta intrusão, preservando as texturas de hibridização, e desenvolvendo superfícies com rigidez suficiente para promover o alinhamento de cristais de plagioclásio por fluxo magmático. Análises isotópicas demonstram um processo de colocação complexo para este corpo, possivelmente envolvendo a filtragem por pressão dos líquidos residuais da cristalização dos pulsos iniciais, além da existência de ante-cristais formados antes da instalação das rochas de granulação grossa. Também é possível reconhecer o processo de assimilação de uma pequena parcela das rochas encaixantes, principalmente pelas rochas das bordas, que decai para o centro da intrusão e é marcado pela migração dos líquidos residuais. Na zona de alimentação, a evolução da colocação é marcada pela diminuição do processo de assimilação pelos pulsos seguintes.

A técnica da Distribuição do Tamanho de Cristais - DTC (Crystal Size Distribution - CSD), que relaciona a densidade de cristais com a distribuição do tamanho, foi aplicada à população de plagioclásio de diques máficos do Enxame de Cabo Frio - Búzios (RJ). Os diques possuem larguras variáveis, de alguns centímetros a 20 metros, e orientação em torno de N45E. A textura dos diques é geralmente fina, localmente microporfirítica e intergranular no centro dos diques mais largos. Bordas resfriadas de alguns centímetros de largura são frequentes nos contatos com as rochas metamórficas encaixantes. Foram estudados dois diques na Praia das Conchas com espessura de 0,8m e 8,2m e, um outro na Praia da Lagoinha, com 2m de largura. As amostras foram coletadas junto às margens (~10 cm do contato) e no centro dos diques. O tamanho médio dos cristais de plagioclásio varia de 0,07 a 0,13 mm na borda dos diques mais finos (<= 2 m de largura) e de 0,09 a 0,20 mm na borda do dique mais largo. No centro do dique de Lagoinha e no dique largo de Praia das Conchas o tamanho de plagioclásio é da ordem de 0,19 ± 0,02 mm e 0,60 ± 0,07 mm, respectivamente. As DTCs nas bordas dos diques, independentemente de sua largura, mostraram um padrão tipicamente encurvado, e que tem sido atribuído na literatura como evidência para misturas de magmas com populações de cristais de tamanhos distintos. No entanto, no centro do dique largo (8,2m) de Praia das Conchas, a DTC é log-linear consistente com uma cristalização magmática simples. A química mineral mostrou que os cristais maiores (precoces) de plagioclásio apresentam um teor mais elevado em An (bytownita-labradorita) que os cristais menores (tardios) da matriz (labradorita-andesina). Além disso, a olivina é mais rica em Fo na borda que no centro do dique e, respectivamente, o piroxênio mais enriquecido em Ca. Esses resultados indicam que as margens resfriadas são mais máficas que o centro sugerindo uma evolução química normal com o resfriamento do magma. Portanto, as DTCs encurvadas provavelmente refletem taxas de cristalização heterogêneas possivelmente induzidas pela despressurização durante a ascensão do magma basáltico seguida de rápido resfriamento. O padrão da DTC log-linear no centro do dique de 8,2m de largura é atribuído ao maior tempo de residência do magma que favoreceria os processos de difusão química e re-equilíbrio textural. Os cálculos da taxa de resfriamento utilizando a inclinação da DTC permitiram estimar que o centro do dique largo da Praia das Conchas estaria completamente cristalizado (~ 900 °C) em torno de 73 dias. O estudo da Orientação Preferencial de Forma (OPF) de plagioclásio mostrou que a petrotrama tende a isotrópica nas margens dos diques com largura menor que 2 metros, o que poderia refletir uma rápida cristalização de plagioclásio por despressurização. Quando a trama é localmente definida, como no dique largo da Praia das Conchas, a lineação de plagioclásio é subhorizontal sugerindo que o fluxo magmático moveu-se predominantemente na lateral do dique. / The method of Crystal Size Distribution (CSD), which relates crystal density with size distribution, has been applied on the plagioclase population of the Mafic Dyke Swarm of Cabo Frio-Búzios (RJ). The dykes are NE-trending with widths from a few centimetres to 20m. The texture is generally fine grained and locally microporphyritic and intergranular at the center of the larger dykes. Chilled margins of a few centimetres in width are common at contacts with the metamorphic basement. Two dykes of 0.8m and 8.2m in width of the Conchas Beach and another of 2m in width at the Lagoinha Beach have been studied. Samples were collected at the margins (~10cm from the contact) and at the center of the dykes. The average characteristic size of the plagioclase crystals varies from 0.07 to 0.13mm at the margins of the narrow dykes (<=2m of width) and from 0.09 to 0.20mm at the margins of the large dyke. At the center of the Lagoinha and Conchas dykes the plagioclase size varies from 0.19 ±0.02mm and 0.60±0.07mm respectively. The CSDs at the dyke margins, irrespective of the dyke width, are typically concave-up, and in literature such patterns have been attributed as evidence of magma mixing with distinct crystal populations. However, at the center of the largest dyke (8.2m) of Conchas Beach, the CSD is log-linear, consistent with simple steady-state crystallization pattern. The mineral chemistry shows that the plagioclase phenocrysts have a high An content (bytownite-labradorite) than the groundmass grains (labradorite-andesine). At the margins olivine is richer in Fo than at the center, and respectively, pyroxene is richer in Ca. These results indicate that the chilled margin is more mafic than the center suggesting a normal chemical evolution in a cooling magma. Nevertheless, the concave-up CSDs probably depict heterogeneous crystallization rates possibly induced by depressurization during the ascent of the basaltic magma followed by rapid cooling. The log-linear CSD pattern at the center of the Conchas dyke (8.2m width) is attributed to a higher residence time of the magma which favors the processes of chemical diffusion and textural re-equilibration. The calculated cooling rates using the CSD slope enables us to estimate that the larger dyke of Conchas would be completely crystallized (at ~900oC) in 73 days. The study of the Shape Preferred Orientation (SPO) in plagioclase shows an isotropic petrofabric at the margins of the dykes <=2m, which could reflect a rapid crystallization of plagioclase by depressurization. When the fabric is defined, as in the larger Conchas Beach dyke, the plagioclase lineation is subhorizontal, suggesting that the magma flow was predominantly lateral to the dyke plane.

Neste trabalho foi desenvolvido um conjunto de ferramentas computacionais, em linguagem de programação Python, para a análise de perfis de difração de raios X, tanto para o estudo quanto para obtenção dos valores microestruturais como tamanhos médios de cristalitos e microdeformações, através de dos métodos de: Scherrer, Single-Line, Williamson-Hall e Warren-Averbach. Para aplicar os métodos de análise de perfis, foram também implementados métodos de remoção da contribuição instrumental pelo método de Stokes e ajuste de funções, remoção de ruídos pelo método de Savitzky-Golay, correção da radiação de fundo pelo método de ajuste linear, correção do fator de Lorentz-Polarização e correção do dubleto Kalfa2 . / In this work, a set of computational tools was developed, in the Python programming language, for the analysis of X-ray diffraction profiles, both for the study and for obtaining the microstructural values, as well as the mean values of crystallites and microdeformations, using Scherrer, Single-Line, Williamson-Hall and Warren-Averbach. To apply the methods of profile analysis, methods were also implemented for the removal of instrumental contributions by the Stokes method and adjustment of functions, removal by the Savitzky-Golay method, correction of the background radiation by the linear adjustment method, correction of the factor of Lorentz-Polarization and correction of dubleto Kalfa2 .

The Limeira Intrusion is an occurrence related to the Mesozoic continental flood basalts of Paraná Magmatic Province, cropping out at the eastern São Paulo state. It is made up of basic- intermediate rocks with a great diversity of structures, textures, and modal compositions, related to the specific evolutionary process in a magma chamber. 2D forward modeling of magnetometric data, based on available aerial and newly obtained ground data integrated with in situ rock magnetic susceptibility measurements, were used to establish its geometry. The results, even considering intrinsic drawbacks of magnetometric theoretical models, are compatible with the geologic-based presumed intrusion geometry. In addition, the stratigraphic analysis of compositional and textural variations, coupled with the structural and geometric features, allowed the interpretation of its emplacement mechanism and thermal evolution. Quantitative textural analysis through crystal size distribution (CSD) of plagioclase crystals, the spatial distribution pattern of structures, microtextures, granulation, and rock-types, evidenced the internal heterogeneities of this occurrence. An approximately 110 m top-to-floor exposure section reveals that its internal heterogeneity was caused by non-instantaneous successive emplacement of three different magma injections. The textural analysis also reveals fine-grained crystals formed under different cooling paths, present in medium- to coarse- grained rocks within the intrusion, next to sharp contacts between different rock compositions. The contacts between different rocks are characterized by hybridization textures and by significant amounts of plumose granophyre-type and plumose plagioclase. The time lapse between consecutive pulses is responsible for a stepwise cooling-path, preservation of hybridization textures, and the development of almost rigid surfaces providing crystals alignment during magma flow. High-resolution Sr-isotopy data demonstrates a complex assembly history, possibly involving filter pressing of residual liquids, and pre-existent crystals before magma installation in coarse-grained rocks. It is also possible to recognize fewer amounts of country-rocks assimilation, which decreases towards the intrusion\'s core and can be associated with magma migration due to filter pressing processes. In the feeder zone, the evolution of emplacement was marked by an almost continuous decrease in wall-rock assimilation by the consecutive magma batches. / A intrusão de Limeira é uma ocorrência associada aos basaltos continentais Mesozoicos da Província Magmática do Paraná, aflorando na região leste do estado de São Paulo. Esta intrusão é composta por rochas básico-intermediárias que ocorrem com grande diversidade de estruturas, texturas e composições modais, relacionados aos mecanismos evolutivos específicos desta câmara. A modelagem magnetométrica bidimensional, baseado em aerolevantamentos disponíveis e dados recentes obtidos em campo e integrados às medidas de suscetibilidade magnética em rocha, foram utilizados para estabelecer sua geometria. Os resultados, mesmo considerando as desvantagens intrínsecas teóricas do método, são compatíveis com o modelo geológico presumido para esta intrusão. Adicionalmente, a análise das variações estratigráficas de composição e texturas, associados aos parâmetros estruturais e geológicos, permitiram a interpretação dos mecanismos de colocação e evolução térmica desta intrusão. Análises texturais quantitativas através da análise de distribuição de tamanho de cristais (DTC), a distribuição espacial de padrões estruturais, microtexturas, granulação e litotipos, evidenciam a heterogeneidade interna desta ocorrência. A seção de aproximadamente 110 metros de topo- a-base revela que sua heterogeneidade interna foi causada pela injeção sucessiva de pelo menos três pulsos magmáticos. Através da análise textural foram reconhecidos cristais de plagioclásio de granulação muito fina a fina presentes em rochas de granulação média a grossa, formados em diferentes razões de resfriamento e próximo ao contato abrupto entre rochas de diferentes composições. Estes contatos caracterizam zonas onde são reconhecidas texturas híbridas e são marcados pela presença e abundância de intercrescimentos granofíricos do tipo plumoso e plagioclásios plumosos. O espaço de tempo entre pulsos magmáticos consecutivos é responsável pela evolução térmica em etapas nesta intrusão, preservando as texturas de hibridização, e desenvolvendo superfícies com rigidez suficiente para promover o alinhamento de cristais de plagioclásio por fluxo magmático. Análises isotópicas demonstram um processo de colocação complexo para este corpo, possivelmente envolvendo a filtragem por pressão dos líquidos residuais da cristalização dos pulsos iniciais, além da existência de ante-cristais formados antes da instalação das rochas de granulação grossa. Também é possível reconhecer o processo de assimilação de uma pequena parcela das rochas encaixantes, principalmente pelas rochas das bordas, que decai para o centro da intrusão e é marcado pela migração dos líquidos residuais. Na zona de alimentação, a evolução da colocação é marcada pela diminuição do processo de assimilação pelos pulsos seguintes.

Neste trabalho foi desenvolvido um conjunto de ferramentas computacionais, em linguagem de programação Python, para a análise de perfis de difração de raios X, tanto para o estudo quanto para obtenção dos valores microestruturais como tamanhos médios de cristalitos e microdeformações, através de dos métodos de: Scherrer, Single-Line, Williamson-Hall e Warren-Averbach. Para aplicar os métodos de análise de perfis, foram também implementados métodos de remoção da contribuição instrumental pelo método de Stokes e ajuste de funções, remoção de ruídos pelo método de Savitzky-Golay, correção da radiação de fundo pelo método de ajuste linear, correção do fator de Lorentz-Polarização e correção do dubleto Kalfa2 . / In this work, a set of computational tools was developed, in the Python programming language, for the analysis of X-ray diffraction profiles, both for the study and for obtaining the microstructural values, as well as the mean values of crystallites and microdeformations, using Scherrer, Single-Line, Williamson-Hall and Warren-Averbach. To apply the methods of profile analysis, methods were also implemented for the removal of instrumental contributions by the Stokes method and adjustment of functions, removal by the Savitzky-Golay method, correction of the background radiation by the linear adjustment method, correction of the factor of Lorentz-Polarization and correction of dubleto Kalfa2 .

A técnica da Distribuição do Tamanho de Cristais - DTC (Crystal Size Distribution - CSD), que relaciona a densidade de cristais com a distribuição do tamanho, foi aplicada à população de plagioclásio de diques máficos do Enxame de Cabo Frio - Búzios (RJ). Os diques possuem larguras variáveis, de alguns centímetros a 20 metros, e orientação em torno de N45E. A textura dos diques é geralmente fina, localmente microporfirítica e intergranular no centro dos diques mais largos. Bordas resfriadas de alguns centímetros de largura são frequentes nos contatos com as rochas metamórficas encaixantes. Foram estudados dois diques na Praia das Conchas com espessura de 0,8m e 8,2m e, um outro na Praia da Lagoinha, com 2m de largura. As amostras foram coletadas junto às margens (~10 cm do contato) e no centro dos diques. O tamanho médio dos cristais de plagioclásio varia de 0,07 a 0,13 mm na borda dos diques mais finos (<= 2 m de largura) e de 0,09 a 0,20 mm na borda do dique mais largo. No centro do dique de Lagoinha e no dique largo de Praia das Conchas o tamanho de plagioclásio é da ordem de 0,19 ± 0,02 mm e 0,60 ± 0,07 mm, respectivamente. As DTCs nas bordas dos diques, independentemente de sua largura, mostraram um padrão tipicamente encurvado, e que tem sido atribuído na literatura como evidência para misturas de magmas com populações de cristais de tamanhos distintos. No entanto, no centro do dique largo (8,2m) de Praia das Conchas, a DTC é log-linear consistente com uma cristalização magmática simples. A química mineral mostrou que os cristais maiores (precoces) de plagioclásio apresentam um teor mais elevado em An (bytownita-labradorita) que os cristais menores (tardios) da matriz (labradorita-andesina). Além disso, a olivina é mais rica em Fo na borda que no centro do dique e, respectivamente, o piroxênio mais enriquecido em Ca. Esses resultados indicam que as margens resfriadas são mais máficas que o centro sugerindo uma evolução química normal com o resfriamento do magma. Portanto, as DTCs encurvadas provavelmente refletem taxas de cristalização heterogêneas possivelmente induzidas pela despressurização durante a ascensão do magma basáltico seguida de rápido resfriamento. O padrão da DTC log-linear no centro do dique de 8,2m de largura é atribuído ao maior tempo de residência do magma que favoreceria os processos de difusão química e re-equilíbrio textural. Os cálculos da taxa de resfriamento utilizando a inclinação da DTC permitiram estimar que o centro do dique largo da Praia das Conchas estaria completamente cristalizado (~ 900 °C) em torno de 73 dias. O estudo da Orientação Preferencial de Forma (OPF) de plagioclásio mostrou que a petrotrama tende a isotrópica nas margens dos diques com largura menor que 2 metros, o que poderia refletir uma rápida cristalização de plagioclásio por despressurização. Quando a trama é localmente definida, como no dique largo da Praia das Conchas, a lineação de plagioclásio é subhorizontal sugerindo que o fluxo magmático moveu-se predominantemente na lateral do dique. / The method of Crystal Size Distribution (CSD), which relates crystal density with size distribution, has been applied on the plagioclase population of the Mafic Dyke Swarm of Cabo Frio-Búzios (RJ). The dykes are NE-trending with widths from a few centimetres to 20m. The texture is generally fine grained and locally microporphyritic and intergranular at the center of the larger dykes. Chilled margins of a few centimetres in width are common at contacts with the metamorphic basement. Two dykes of 0.8m and 8.2m in width of the Conchas Beach and another of 2m in width at the Lagoinha Beach have been studied. Samples were collected at the margins (~10cm from the contact) and at the center of the dykes. The average characteristic size of the plagioclase crystals varies from 0.07 to 0.13mm at the margins of the narrow dykes (<=2m of width) and from 0.09 to 0.20mm at the margins of the large dyke. At the center of the Lagoinha and Conchas dykes the plagioclase size varies from 0.19 ±0.02mm and 0.60±0.07mm respectively. The CSDs at the dyke margins, irrespective of the dyke width, are typically concave-up, and in literature such patterns have been attributed as evidence of magma mixing with distinct crystal populations. However, at the center of the largest dyke (8.2m) of Conchas Beach, the CSD is log-linear, consistent with simple steady-state crystallization pattern. The mineral chemistry shows that the plagioclase phenocrysts have a high An content (bytownite-labradorite) than the groundmass grains (labradorite-andesine). At the margins olivine is richer in Fo than at the center, and respectively, pyroxene is richer in Ca. These results indicate that the chilled margin is more mafic than the center suggesting a normal chemical evolution in a cooling magma. Nevertheless, the concave-up CSDs probably depict heterogeneous crystallization rates possibly induced by depressurization during the ascent of the basaltic magma followed by rapid cooling. The log-linear CSD pattern at the center of the Conchas dyke (8.2m width) is attributed to a higher residence time of the magma which favors the processes of chemical diffusion and textural re-equilibration. The calculated cooling rates using the CSD slope enables us to estimate that the larger dyke of Conchas would be completely crystallized (at ~900oC) in 73 days. The study of the Shape Preferred Orientation (SPO) in plagioclase shows an isotropic petrofabric at the margins of the dykes <=2m, which could reflect a rapid crystallization of plagioclase by depressurization. When the fabric is defined, as in the larger Conchas Beach dyke, the plagioclase lineation is subhorizontal, suggesting that the magma flow was predominantly lateral to the dyke plane.

Magmatic processes are major agents responsible for the formation and differentiation of the Earth's crust. In contrast to extensive efforts to improve understanding and utility of igneous geochemistry, physical processes of magma differentiation and solidification remain largely unclear. Large variability of igneous textures provides record of these processes and intensive parameters governing the crystallization. In this thesis, we develop quantitative methods, which allow us to better interpret igneous textures in the framework of physics of solidification. We have developed a new three-dimensional model of crystallization from one- component melt driven by homogeneous and heterogeneous nucleation and crystal growth. The predicted textures are quantitatively characterized by crystal size distributions, spatial distribution functions and parameters representing grain contact relationships. The model employs high resolution in a large volume simulation domain in order to produce statistically stable results. Our simulations, performed for various functional forms of nucleation and growth rates with respect to time, imply that (i) crystals are ordered (anti-clustered) on short length scales. This reflects that other crystals already have a finite size at the time of nucleation of younger crystal,...

Dans le but d'étudier l'impact de la taille et de la morphologie de cristaux zéolitiques sur les propriétés texturales, chimiques et diffusionnelles, une série de zéolithe beta a été étudiée.L'augmentation logique des surfaces et des volumes poreux avec la diminution de la taille des cristaux est constatée. En outre, cela implique également une baisse de l'acidité globale ainsi que de la force des sites. Toutefois, la compréhension de l'acidité complexe de ces matériaux nécessite des techniques poussées de caractérisation.L'adsorption de molécules sondes (pyridine, CO, éthylène) suivie par infrarouge ainsi que la thermodésorption d'ammoniac ont été corrélées à des réactions modèles de transformation de l'éthanol et de craquage du n-hexane. Lors de celui-ci, la morphologie des cristaux a peu d'influence et les performances sont dictées par les sites de Brønsted. La présence d'aluminiums extra-réseaux permet d'exalter la force acide des sites protoniques. Avec la transformation de l'éthanol, de meilleures activités et stabilités sont observées dans le cas de zéolithes hiérarchisées.L'étude de la diffusion par chromatographie en phase gaz à flux inversées (RF-IGC) a permis de montrer que, si les coefficients de diffusion augmentent à l'opposé de la taille des cristaux, la porosité secondaire réduit le chemin diffusionnel. De plus, les sites faibles majoritairement présents sur les matériaux hiérarchisés facilitent la désorption des molécules et sont impliqués dans les interactions latérales mesurées par RF-IGC.Ce travail apporte donc des éléments de réponse à la stabilité et aux comportements catalytiques complexes observés sur la zéolithe beta. / In order to study the impact of the size and morphology of zeolite crystals on the textural, chemical and diffusion properties, a series of beta zeolites was studied.The logical increase of the porous surfaces and volumes with the decrease in crystal size is observed. In addition, this also implies a decrease in the overall acidity as well as strength of the adsorption sites. However, understanding the complex acidity of these materials requires advanced characterization techniques.The adsorption of probe molecules (pyridine, CO, ethylene) followed by infrared as well as ammonia thermodesorption were correlated to model reactions of ethanol conversion and n-hexane cracking. In this case, the morphology of the crystals has little influence and performance is mainly dictated by the Brønsted sites. The presence of extra-framework aluminums makes it possible to exalt the acid strength of the protonic sites. With the transformation of ethanol, better activities and stabilities are observed in the case of hierarchical zeolites.The study of diffusion by the reversed-flow gas chromatography (RF-IGC) showed that if the diffusion coefficients increase as opposed to crystal size, the secondary porosity reduces the diffusion path. Moreover, the weak sites predominantly present on the hierarchized materials facilitate the desorption of the molecules and are involved in the lateral interactions measured by RF-IGC.This work thus provides elements of response to the stability and the complex catalytic behaviors observed on the beta zeolite.