This study shows how the use of modern geological investigative techniques can reopen old, “drained” hydrocarbon fields. Specifically, it looks at the White Castle Field in South Louisiana. This field has pay sections ranging from late Oligocene to late Miocene. The late Oligocene package is underexplored and understudied and contains 3 primary reservoirs (Cib Haz (CH), MW, and MR). This study established the depositional history of these reservoirs. During most of the late Oligocene, the White Castle Salt Dome was located in a minibasin on the continental slope. The CH and MW deposited in this minibasin. The CH is an amalgamation of slumped shelfal limestones, sandstones, and shales deposited during a lowstand systems tract (LST). The MW comprises a shelf-edge delta that is part of a LST. The MR is an incised valley fill located in the continental shelf that was deposited during LST after the minibasin was filled.

Rare earth elements (REE) are an increasingly important group of metals due to their role in the development of modern technologies. Despite being abundant within the Earth’s crust recoverable ores are uncommon, and their mineralization isn’t as well understood as other abundant ore types. In this work, the mineralization of REE occurring in outcrop samples at Hicks Dome, a cryptoexplosive feature that resides in the Wauboukigou Alnöite Province in southeastern Illinois, was studied to determine the mode of mineralization and the origin of the REE. Xenotime-(Y) was identified with a scanning electron microscope in an intrusive breccia and emplaced during or shortly after the uplift which created the oval doming of the Paleozoic section. Whole rock REE concentrations from ultramafic dikes at Hicks Dome closely match global averages of lamprophyres and carbonatites, with a steep La to Lu slope, and enrichment of light rare earth elements. Hicks Dome has unique characteristics relative to the other intrusions in the Province, such as elevated REE, Th, and doming. These traits indicate that the dome was more closely related to an intrusive body at depth that sourced heat, volatile gases, and a suite of rare elements. Based on these data, the REE mineralization and thorium associated with the siliceous breccia is directly related to the alkaline ultramafic intrusion at Hicks Dome. The volatile rich, hot fluids emanating from the ultramafic magma supplied REE and thorium were mixed with the regional fluids responsible for the IKFD.

Obsidian Dome is a 550-650 year old, 1.5 by 1.8 km extrusion of high silica rhyolite situated along the Inyo Craters in eastern California. Field, and observations of drill core, reveals discrete metre-scale thick zones of rhyolitic glass exposed along the margin of Obsidian Dome as well as within its interior. Millimetre-scale flow-banded obsidian, pumice and rhyolite range from planar to chaotically folded, the latter a product of ductile, compressive deformation. Fractures, some of which display en-echelon splitting patterns are a result of brittle failure. Taken together, these features along with others, result from flow during lava dome growth and suggest complex emplacement patterns signified by vesiculation, crystallization and repeated brittle-ductile deformation, owing to episodic crossing of the glass transition. Evidence further shows that gas loss from the system occurred due to explosions, pumice formation and also brecciation of the melt as it episodically crossed the glass transition. Loss of gas by these mechanisms along with the inherent high viscosity of rhyolite melt explains the large amount of glass found on and within Obsidian Dome and other similar rhyolite extrusions in comparison to less silica-rich systems.

Head tracking is an important way to interact with virtual objects in virtual world. The viewercan move or rotate his head to observe the 3D scene in dierent view. Normally head tracking isused in a cave or just on a at screen.Dome theater has a half sphere screen with multiple projectors together for showing the wholescene onto the big screen. The dome screen could give the viewer a very strong immersion feelingwhen head tracking inside dome theater and that is why we want to implement head tracking indome theater. The half sphere dome screen is so big that multiple projectors should be used forshooting the whole scene onto the big screen. Hence a cluster system is used for manipulating allthe projectors working smoothly. The display system of dome theater has no place for the headtracking part.This thesis tries to introduce a method to do head tracking in dome theater. The mainproblem is how to add head tracking in the display system in dome theater. Frame buer object(FBO) is used as the solution for this problem. The viewer's viewing frustum is created in framebuer object in order to render the 3D scene depending on the viewer's head position. The FBOtexture will then be attached onto a 3D sphere which simulates the dome sphere in virtual world.Since the viewing frustum is always created depending on the viewer's head position, the FBOtextures on the 3D sphere always can represent the 3D scene rendered depending on the viewer'shead position. Using the projectors to shoot the 3D scenes which is the 3D sphere attached by theFBO textures onto the dome screen. That is the main part of how to implement head tracking indome theater.This thesis forcus on rendering the 3D scene onto the dome screen depending on the viewer'shead position. The tracking device controlling part is out of this thesis's scope. VR Juggler (VRJ) is used as the framework in this project. Viewer's position setting and cluster setting are allsetted in the conguration file.

The evolution of rhyolitic lava from effusion to cessation of activity is poorly understood. Recent lava dome eruptions at Unzen, Colima, Chaiten and Soufrière Hills have vastly increased our knowledge on the changes in behaviour of active domes. However, in ancient domes, little knowledge of the evolution of individual extrusion events exists. Instead, internal structures and facies variations can be used to assess the mechanisms of eruption. Rhyolitic magma rising in a conduit vesiculates and undergoes shear, such that lava erupting at the surface will be a mix of glass and sheared vesicles that form a permeable network, and with or without phenocryst or microlites. This foam will undergo compression from overburden in the shallow conduit and lava dome, forcing the vesicles to close and affecting the permeable network. High temperature, uniaxial compression experiments on crystal-rich and crystal-poor lavas have quantified the evolution of porosity and permeability in such environments. The deformation mechanisms involved in uniaxial deformation are viscous deformation and cracking. Crack production is controlled by strain rate and crystallinity, as strain is localised in crystals in crystal rich lavas. In crystal poor lavas, high strain rates result in long cracks that drastically increase permeability at low strain. Numerous and small cracks in crystal rich lavas allow the permeable network to remain open (although at a lower permeability than undeformed samples) while the porosity decreases. Flow bands result from shear movement within the conduit. Upon extrusion, these bands will become modified from movement of lava, and can therefore be used to reconstruct styles of eruption. Both Ngongotaha and Ruawahia domes, from Rotorua caldera and Okataina caldera complex (OCC) respectively, show complex flow banding that can be traced to elongated or aligned vents. The northernmost lobe at Ngongotaha exhibits a fan-like distribution of flow bands that are interpreted as resulting from an initial lava flow from a N – S trending fissure. This flow then transitioned into intrusion of obsidian sheets directly above the conduit, bound by wide breccia zones which show vertical movement of the sheets. Progressive intrusions then forced the sheets laterally, forming a sequence of sheets and breccia zones. At Ruawahia, the flow bands show two types of eruption; long flow lobes with ramp structures, and smaller spiny lobes which show vertical movement and possible spine extrusion. The difference is likely due to palaeotopography, as a large pyroclastic cone would have confined the small domes, while the flow lobes were unconfined and able to flow down slope. The vents at Ruawahia are aligned in a NE – SW orientation. Both domes are suggested to have formed from the intrusion of a dyke. The orientations of the alignment or elongation of vents at Ngongotaha and Ruawahia can be attributed to the overall regional structure of the Taupo Volcanic Zone (TVZ). At Ngongotaha, the N – S trending elongated vent is suggested to be controlled by a N – S trending caldera collapse structure at Rotorua caldera. The rest of the lobes at Ngongotaha, as well as other domes at Rotorua caldera, are controlled by the NE – SW trending extensional regional structure or a NW – SE trending basement structure. The collapse of Rotorua caldera, and geometry of the deformation margin, are related to the interplay of these structures. At Ruawahia, the NE – SW trending vent zone is parallel to the regional extension across the OCC, as shown by the orientation of intrusion of the 1886AD dyke through the Tarawera dome complex. The NE – SW trending regional structures observed at both Rotorua caldera and Okataina caldera complex are very similar to each other, but differ from extension within the Taupo rift to the south. Lava domes, such as Ngongotaha, that are controlled by this structure show that the ‘kink’ in the extension across Okataina caldera complex was active across Rotorua caldera during the collapse at 240 ka, and possibly earlier. This study shows the evolution of dyke-fed lava domes during eruption, and the control of regional structures in the location and timing of eruption. These findings improve our knowledge of the evolution of porosity and permeability in a compacting lava dome, as well as of the structures of Rotorua caldera, the longevity of volcanic activity at dormant calderas and the hazard potential of dyke-fed lava domes.

Obsidian Dome is a 550-650 year old, 1.5 by 1.8 km extrusion of high silica rhyolite situated along the Inyo Craters in eastern California. Field, and observations of drill core, reveals discrete metre-scale thick zones of rhyolitic glass exposed along the margin of Obsidian Dome as well as within its interior. Millimetre-scale flow-banded obsidian, pumice and rhyolite range from planar to chaotically folded, the latter a product of ductile, compressive deformation. Fractures, some of which display en-echelon splitting patterns are a result of brittle failure. Taken together, these features along with others, result from flow during lava dome growth and suggest complex emplacement patterns signified by vesiculation, crystallization and repeated brittle-ductile deformation, owing to episodic crossing of the glass transition. Evidence further shows that gas loss from the system occurred due to explosions, pumice formation and also brecciation of the melt as it episodically crossed the glass transition. Loss of gas by these mechanisms along with the inherent high viscosity of rhyolite melt explains the large amount of glass found on and within Obsidian Dome and other similar rhyolite extrusions in comparison to less silica-rich systems.

Obsidian Dome is a 550-650 year old, 1.5 by 1.8 km extrusion of high silica rhyolite situated along the Inyo Craters in eastern California. Field, and observations of drill core, reveals discrete metre-scale thick zones of rhyolitic glass exposed along the margin of Obsidian Dome as well as within its interior. Millimetre-scale flow-banded obsidian, pumice and rhyolite range from planar to chaotically folded, the latter a product of ductile, compressive deformation. Fractures, some of which display en-echelon splitting patterns are a result of brittle failure. Taken together, these features along with others, result from flow during lava dome growth and suggest complex emplacement patterns signified by vesiculation, crystallization and repeated brittle-ductile deformation, owing to episodic crossing of the glass transition. Evidence further shows that gas loss from the system occurred due to explosions, pumice formation and also brecciation of the melt as it episodically crossed the glass transition. Loss of gas by these mechanisms along with the inherent high viscosity of rhyolite melt explains the large amount of glass found on and within Obsidian Dome and other similar rhyolite extrusions in comparison to less silica-rich systems.

Please read the abstract in the thesis. / Thesis (PhD)--University of Pretoria,1969. / gm2015 / Plant Production and Soil Science / PhD / Unrestricted

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La peau est organisée en niche de cellules souches/progénitrices qui contribuent au maintien des lignées épidermiques pendant l’homéostasie permettant ainsi de conserver l’intégrité du tissue. Les différentes cascades de signalisation qui régulent cet équilibre sont essentielles et la perturbation de ces voix peuvent amener à une différentiation anormale des kératinocytes, pouvant engendrer des cancers de la peau. Le but de cette thèse était d’identifier et de caractériser la population de progéniteurs responsables de la maintenance d’une niche épidermique spécialisée dans la mechanotransduction du toucher léger appelée les cellules de Merkel. Mon étude a porté sur le rôle des progéniteurs épithéliaux localisés dans le dôme du toucher (DT) de l’épiderme dans des conditions d’homéostasie ainsi que sur le développement du carcinome des cellules de Merkel. Basé sur l’analyse de données de microarray, j’ai identifié une nouvelle population de progéniteurs qui expriment de manière spécifique Kératine 17 (K17). Des expériences de traçage de lignées cellulaires démontrent que ces cellules donnent naissance aux cellules de Merkel (CM) ainsi qu’aux cellules squameuses. De plus, l’ablation génétique sélective des progéniteurs des CMs dans le DT a montré que cette niche est isolée et indépendante du reste de l’épiderme. Ces résultats établissent les CMs comme la quatrième lignée cellulaire de la peau. Cette découverte a permis l’établissement de nouveaux outils pour l’étude de conditions pathologiques associées à la lignée des cellules de Merkel, telles que les carcinomes des cellules de Merkel et le déclin du toucher léger avec l’âge. / The skin is organized in highly regionalized stem or progenitor cell niches that are in charge of maintaining all epidermal lineages during homeostasis. Disruption of molecular pathways that tightly regulate this balance leads to abnormal specification and differentiation of keratinocytes, eventually causing skin cancer. The goal of this thesis was to identify and characterize the progenitor population responsible for the maintenance of an epidermal niche specialized for mechanosensory signaling: the Merkel cell lineage. This work focused on the role of the epithelial progenitors located in the touch dome (TD) of hairy skin under homeostatic conditions and in a Merkel cell carcinoma (MCC) context. Based on previous microarray data, I first identified a distinct population of the interfollicular epidermis uniquely expressing Keratin 17 (K17). By lineage tracing analysis, I demonstrated that these cells give rise to the Merkel cell (MC) and squamous lineage. More importantly, selective genetic ablation of K17+ TD keratinocytes (TDKC) showed that the TD is a self-autonomous niche defining it as the 4th lineage of the skin. Interestingly, TDKCs may be involved in maintaining innervation of the Merkel cell-neurite complex. These critical results have established a new plateform for the field to allow studies of pathological skin conditions such as Merkel cell carcinoma and the loss of tactile acuity with age.