Thesis (Ph. D.)--University of California, San Diego, 1997. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of California, Santa Cruz, 1994. / Typescript. Includes bibliographical references (leaves 83-85).

Calcium bentonite deposits of the Glendon and Bucatunna formations of the Oligocene Vicksburg Group located in Smith County, Mississippi were examined to determine the depositional environment, diagenetic history and origin of the bentonite. Traditionally, calcium bentonite was considered to be the product of the weathering of volcanic ash deposits. The hypothesis tested is that the bentonite deposits are not a result of weathered volcanic ash, but are a result of weathered marl. Core samples were drilled from the Chisholm bentonite mine in Smith County and were studied using X-ray diffraction, scanning electron microscopy, and petrographic microscopy. Abundant bacteria along with nanometer-scale organic textures were found throughout and are consistently associated with bentonite, illite, and smectite. No evidence of volcanic ash was found. It appears that the calcium bentonite clays in the Glendon and Bucatunna formations of Smith County, Mississippi formed from weathering, including bacterial activity, of glauconite-bearing marl.

¡@¡@Igneous activity of Taiwan in Miocene mainly were concentrated in the area north of Miaoli. Nanman is one of the basalt in southern of Taiwan that had been studied by OM, XRD, SEM/EDS and TEM. The rock type is alkali basalt with phenocryst of augite and olivine. The primary minerals include olivine + augite + plagioclase + Anorthoclase + apatite +titanomagnetite + illmenite, and secondary minerals are chlorite + smectite + calcite ¡Ó gypsum.Alteration of Nanman basalt was take placed in mixture and crack of olivine, other minerals are almost fresh. The main replacement are chloritic minerals shown five occurrence types : (1) replaced mixture, (2) vein center of olivine crack, (3) vien of olivine, (4) fibrous and (5) mica-like clay between vein and residual olivine. Each types has clear grain boundary. It¡¦s mean they are not gradual. (4) and (5) are smectite with anomaly composititon. It cause by lack of Al resource, and smectite occurred far from the crack that element do not easily move. Thus, smectite replaced olivine often showed Al-poor and excess Mg. Si/(Si+Al) and Fe/(Fe+Mg) in smectite is positive correlation. This may be considered the moving ability of elements. Composition of (1), (2) and (3) are chlorite/smectite. However there is no observed mixed-layer minerals in XRD. According to TEM , they are chlorite + smectite. Chlorite within abundant of dehydrated cracks could be a evidence of smectite. Because of mixed chlorite and smectite, the correlation between Si/(Si+Al) and Fe/(Fe+Mg) is negative. Different occurrences lead to different mineral, suggest water/rock ratio is an important control factor. High rock/water ratio trend to form chlorite, and low rock/water ratio prefer to form smectite. According to all the results, the steps of altered olivine are first forming chlorite at mixture and olivine cracks. Then, the residual olivine becomes smectite with poor Al and excess Mg, when the rock was cooling down.

Thesis (Ph.D.)--Memorial University of Newfoundland. / Typescript. Restricted until May 1997. Bibliography: leaves 218-234. Also available online.

Thesis (Ph. D.)--University of California, Santa Cruz, 1993. / Typescript. Includes bibliographical references.

Smectite clay minerals are among the most common minerals in subduction zone megathrusts faults at shallow depth and in landslide decollements. Consequently, deformation processes at seismic slip rates (ca. 1 m/s) in smectites contribute to control the mechanics of megathrust earthquakes and landslide collapses. To investigate the deformation processes, rotary shear experiments on smectite-rich gouge layers (70/30 wt.% Ca-montmorillonite/opal) were performed. The experiments were conducted at ambient temperature and at 5 MPa normal stress. The gouges were sheared under vacuum (<0.001 mbar) and room humidity (i.e., water depleted) or in the presence of liquid water (i.e., water rich) conditions, at slip rates of 0.0003 <V <1.5 m/s and displacements of 0.1 <d <30 m. The temperature evolution with slip was measured with thermocouples and modelled numerically. Permeability of the gouge layer was measured with the pore pressure oscillation method prior to the rotary experiments. Before and after the experiments, the mineral and amorphous material content in wt.% were determined via quantitative X-ray powder diffraction and the microstructures investigated via scanning and transmission electron microscopy. The activation of deformation processes was strongly controlled by the water content of the gouge layers. Under water depleted conditions, grainsize reduction producing nanoparticles controlled the evolution of the friction coefficient f at all slip rates. Coseismic dynamic weakening (f = 0.2 - 0.3) occurred by combined thermal decomposition or melting (with decreasing water content) and pressurization of water released by dehydration of smectite interlayer. Under water rich conditions, grain size reduction was minor and development of nano-foliations occurred. At all slip rates, the friction coefficient rapidly decreased at the onset of slip. The large initial weakening (to f <0.15) was due to the presence of a film of water lubricating the surfaces of the sub-parallel smectite grains forming the nano-foliation in combination with shear-enhanced water pressurization. Then, friction coefficient evolved depending on the balance between dissipation of pore pressures, dehydration of smectite interlayer and thickening of the nano-foliation layers. At higher displacement and slip rates, sustained dynamic weakening was aided by vaporization of pore water. Expulsion of water determined a switch to deformation processes typical of water depleted conditions. In nature, the presence of liquid water in smectites has a lubricating effect, pressurizes the slipping zone and renders the smectite-rich gouges prone to accommodate large seismic slips. During megathrust earthquakes, such lubricating effect may result in the easy propagation of seismic ruptures in smectite- and water-rich sediments at shallow depths. Similarly, the presence of water can promote large displacements during landslide collapse.

Les compartiments aquatiques sont pollués par des micropolluants d’origine anthropique, tels les produits pharmaceutiques. Ces pollutions sont principalement engendrées par le rejet continu des effluents des stations d’épuration les eaux naturelles. C’est pourquoi le premier objectif de ce travail fut de caractériser les capacités épuratoires des trois types de station d’épuration actuellement utilisées, les boues activées, les lagunages naturels et les filtres plantés. Les analyses des effluents ont démontré que l’épuration des produits pharmaceutiques dans ces stations est insuffisante. Il est donc nécessaire, notamment dans le cadre de le directive cadre sur l’eau, de penser à des traitements innovants et à bas coût. De part des propriétés d’adsorption significatives, les argiles naturelles comme les smectites sont des matériaux qui ont un potentiel en ce sens. Le second objectif de ce travail a donc été de mettre en interaction la smectite naturelle avec les produits pharmaceutiques dans différentes conditions expérimentales. En débutant par des conditions standards à concentrations dopées pour aboutir à des solutions naturelles. Les expérimentations ont également été menées sous différentes dynamiques pour vérifier l’adéquation du matériau choisi avec un usage en conditions industrielles. Les résultats démontrent que la smectite a une capacité d’adsorption significative sur une grande variété de produits pharmaceutiques et que cette capacité est meilleure dans des solutions complexes. Ceci permet de postuler que le matériau choisi peut représenter une solution à bas coût et efficace pour l’épuration des effluents des stations d’épuration. / The water compartments are contaminated by anthropic micropollutants, as pharmaceuticals. These pollutions are mainly due to the constant spillage of effluents in natural waters. That’s why the first objective of this study was to evaluate the removal capacity of three treatment chains, activated sludge, lagoon-based system and planted filter. The effluent analyses exhibited that the removal of pharmaceuticals in these sewage plants is insufficient. It is thus necessary to think about low cost and innovative purification solution especially framed by the water framework directive. Due to significant adsorptions properties, natural clay minerals as smectites have a potential in that way. The second objective of this work was thus to realize organo-mineral interactions between the smectite and pharmaceuticals in different experimental conditions. Beginning with standard conditions and boosted concentrations to finish with natural solutions. To verify the field use of the chosen material, differents dynamics were tested. Results demonstrated that the smectite has a significant sorption capacity on a wide variety of pharmaceuticals and that this capacity is enhanced in complex solutions. This permit to postulate, that the chosen material can represent an efficient low-cost solution for the purification of the effluents of sewage treatment plants.

Abstract The Surma basin is a part of the Bengal Basin situated in northeastern Bangladesh. The presence of eight gas fields and one oil field makes this an area that is interesting both economically and geologically. In spite of detailed geological and geophysical investigations, information available on palynostratigraphy and geochemistry for the area is scanty. The aim of the present work was to investigate the palynological assemblages, mineralogy and geochemistry of the Surma Group (SG) sequences in Surma Basin, Bangladesh. Core samples (n = 188) were gathered from the wells following: Patharia well-5, Rashidpur well-1, Atgram well-IX, Habiganj well-1, Kailastila well-1 and Fenchuganj well-2. They were provided by BAPEX (Bangladesh Petroleum Exploration Company). X-ray Fluorescence (XRF), Atomic Absorption Spectrometry (AAS), Loss of Ignition (LOI), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used for geochemical and mineralogical study of shale samples. In the palynological study, the distributions of pollens and spores were determined. For data analysis, SPSS computer programme was used. Palynological assemblages of the Surma Group of sedimentary sequence of Bangladesh include taxa range in age from the lower Miocene to the Upper Miocene which can be potentially used in dating and correlation. The Lower Miocene interval is correlated with the Simsang Palynological Zone IV of Meghalaya, India and the Bengal Palynological Zone (BPZ) V. The Upper Miocene is correlated with the Simsang Palynological Zone IV of Meghalaya, India and the BPZ Zone V of Bengal. They were deposited in two types of paleoenvironments ranging from the brackish type to shallow marine to brackish. The sequence contains reworked palynomorphs of BPZ IV and III namely Meyeripollies naharkotensis, Polypodiesporites Oligocenecus, Palmepollenities Eocencus and ornamented Tricolpate pollen of the Eocene-Oligocene age which are mainly encountered in the lower Miocene sediments indicative of increased tectonic activity in the area. Geochemical ratios (SiO2/ Al2O3, Cu/Zn, Maturity = K2O+ Al2O3/Na2O+MgO, Rb/K2O, K2O/Na2O, Cr/Rb, Zr/Rb, V/Rb, Th/U etc.) were useful for determining grain size, maturity, tectonics and environment of deposition. High Ba enrichment was detected in the Patharia well-5 and showed high surface water productivity and diagenetic mobilisation. Tectonic descrimination was achieved using SiO2 and K2O/Na2O ratio. XRD analysis revealed the minerals kaolinite, illite, chlorite, illite/smectite (I/S) and kaolinite/smectite (K/S) mixed layers. Kaolinite/Smectite here reported for the first time in Bangladesh. Clay mineral analyses provided evidence for diagenesis. Smectite diagenesis and dehydration have contributed to the generation of overpressure in the Bhuban Formation in the Patharia well -5. Geochemical ratios of the present study from the Surma Basin is undoubtedly a powerful technique and can be applied to any sedimentary basin analysis to infer the palaeoenvironment, palaeoclimate and palaeotectonics.

Une étude multi-échelle du gonflement d’une smectite en milieu confiné est proposée par une analyse de la pression de gonflement et de la porosité à différentes échelles (inter-agrégat, inter-particulaire, interfoliaire). Un dispositif spécifique, œdo-tomomètre, est conçu pour assurer le suivi couplé de la pression de gonflement et de la porosité inter-agrégat identifiable par microtomographie de rayon X (taille > 5 µm). D’autres analyses par adsorption de gaz et en microscopie permettent de caractériser la porosité à plus petites échelles. Différents types de fluides sont utilisés pour hydrater les éprouvettes afin de contrôler les composantes cristalline et osmotique du gonflement (solutions de NaCl à différentes forces ioniques et solution de méthacrylate de méthyle (MMA)). Les résultats obtenus en comparant notamment les éprouvettes hydratées par des solutions ioniques de NaCl à celles hydratées par du MMA montrent que l’évolution de la pression de gonflement et la réorganisation de la microstructure (diminution en taille de la porosité inter-agrégat, fractionnement possible des particules) sont intimement liées. Par ailleurs, ces résultats comparés à ceux calculés par des modèles phénoménologiques (BExM par exemple, modèle de Barcelone pour les sols gonflants) sont assez bien corrélés / A multi-scale investigation of the swelling behaviour of a purified bentonite under constrained conditions is carried out by a monitoring of the swelling pressure and the porosity evolution at various scales (inter-aggregate, inter-particle, interlayer). A specific oedometer, oedo-tomometer, has been designed to monitor both the swelling pressure and the inter-aggregate porosity evolution deduced from microfocus X-ray computed tomography measurements (size higher than 5 µm). Further investigations of the porosity at lower scale were conducted at various stages of the swelling process by gas adsorption mainly and transmission electron microscopy. Various fluids were used for specimen hydration to control either crystalline swelling or osmotic swelling (NaCl solutions at different ionic strengths and methyl methacrylate (MMA) solution). The results, which combined both swelling pressure measurements and quantification of microstructure evolution upon hydration for the two different solutions, give sound understanding on the development of osmotic and/or crystalline swelling and their relative impact both on the microstructure and on the magnitude of the macroscopic swelling pressure of compacted smectites. Furthermore, these results compared to calculated results (BExM for example) shows similar evolutions