Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on June 07, 2010). Includes bibliographical references (p. 96-103).

Thesis (M.S.) -- University of Tennessee, Knoxville, 2005. / Title from title page screen (viewed on Feb. 6, 2006). Thesis advisor: William M. Dunne. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Made available in DSpace on 2014-06-11T19:33:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-18Bitstream added on 2014-06-13T20:24:48Z : No. of bitstreams: 1 hardt_r_dr_rcla.pdf: 4572815 bytes, checksum: 0c1bd7aa44b19280926515147be7a636 (MD5) / L’existence de karsts dans les grès a été longtemps sujette à controverse, mais est de plus en plus acceptée depuis les dernières décennies par les karstologues. Le sous-sol d’une grande partie du territoire brésilien se constitue de grès et de métagrès. Des pluies abondantes, un couvert végétal et une matière organique abondante liés au climat tropical caractérisant majoritairement le pays, la présence d’oxydes de fer et de périodes d’érosion physicochimique prolongées ont favorisé l’altération chimique des quartz. Cette combinaison de facteurs a produit une grande variété de reliefs karstiques, ainsi que leur organisation sous la forme de systèmes karstiques gréseux. Quatre zones ont été étudiées en détail afin de comparer et de caractériser la morphologie karstique et les systèmes karstiques dans cette lithologie. Au Brésil, il s’agit de la Serra d’Itaqueri, de la Chapada dos Guimarães et de la région de Campos Gerais. En France, nous avons examiné les morphologies associées aux grès de la forêt de Fontainebleau. En outre, d'autres sites ont été visités afin de recueillir des données comparatives permettant une meilleure compréhension des processus morphogénétiques et de l'organisation des reliefs. Cette étude démontre la nature karstique des formes rencontrées et apporte une meilleure compréhension à leur intégration dans les paysages et leur intégration systémique. Les connaissances ainsi acquises autorisent la formulation d’une série d’hypothèses sur les processus impliqués dans la structuration de ces reliefs et des systèmes karstiques. L’influence de la végétation est soulignée, notamment comme... (Résumé complet accès életronique cidessous) / A carstificação dos arenitos já foi considerado um tema polêmico no passado, mas nas últimas décadas, vem sendo cada vez mais aceito pela comunidade de pesquisadores do carste. No Brasil, uma ampla área do território possui afloramentos de arenitos e meta-arenitos, e o clima tropical, com abundância de chuva e vegetação, associado a presença de matéria orgânica, óxidos de ferro, sais e longo tempo de exposição às intempéries, entre outros elementos, permitem uma aceleração do processo de intemperismo químico do quartzo, produzindo uma ampla variedade de formas cársticas, além de uma organização espacial, permitindo-se falar em Sistemas Cársticos em Arenitos. Visando a comparação e a caracterização da morfologia cárstica e dos sistemas cársticos nesta litologia, quatro áreas foram estudadas com maior grau de detalhamento, bem como outras áreas foram visitadas, com a ideia de fornecer subsídios comparativos na compreensão dos processos e organização, através do estudo das formas. As áreas estudadas foram a Serra de Itaqueri; a Chapada dos Guimarães, e a região dos Campos Gerais, no Brasil, e a região da Forêt de Fontainebleau, na França. Conseguiu-se, com isso, demonstrar a natureza cárstica das formas de relevo encontradas, entender a organização destas formas na paisagem e sua integração sistêmica, e fornecer subsídios para a formulação de hipóteses dos processos envolvidos na estruturação de tais formas e sistemas, sobretudo da importância da cobertura vegetal, como auxiliar na dissolução do quartzo, e do processo de “fantomização” da rocha (alteração “in situ”) e posterior remoção, por dissolução completa ou mecanicamente, da matéria alterada, resultando em formas e sistemas cársticos... / Karstification of sandstone was considered a controversial topic in the past, but has become increasingly accepted by karst researchers in recent decades. A large area of Brazil’s territory has sandstone and metasandstone outcrops. The country’s tropical climate, abundant rainfall and vegetation, allied to the presence of organic matter, iron oxides, salts and long weathering processes, among other factors, accelerate the chemical weathering of quartz. This combination of factors has produced a wide variety of karst landforms, as well as a spatial organization, that allows them to be referred to as Sandstone Karst Systems. Four areas were studied in great detail to compare and characterize the karst morphology and karst systems in this lithology. In addition, other areas were visited to collect comparative data to help shed further light on geological processes and the organization of landforms. The areas under study were Serra de Itaqueri, the Chapada dos Guimarães, and the region of Campos Gerais in Brazil, and the region of Forêt de Fontainebleau in France. This study allowed for the determination of the karst topography and an understanding of the organization of these landscape processes and their systemic integration. The knowledge thus gained served to underpin the formulation of hypotheses about the processes involved in the structuring of these landforms and systems, and above all the importance of vegetation as an aid for quartz dissolution, and about the process of rock phantomization (in situ alteration) and subsequent removal of modified material by complete dissolution or by mechanical means, resulting in karst landforms and systems. The aforementioned hypotheses served as the basis for a proposal to amend the definition of karst with respect to the term... (Complete abstract click electronic access below)

Philosophiae Doctor - PhD / Petrophysical evaluation of the Albian age gas bearing sandstone reservoirs of the O-M field, Offshore South Africa has been performed. The main goal of the thesis is to evaluate the reservoir potentials of the field through the integration and comparison of results from core analysis, production data and petrography studies for the evaluation and correction of key petrophysical parameters from wireline logs which could be used to generate an effective reservoir model. A total of ten wells were evaluated and twenty eight sandstone reservoirs were encountered of which twenty four are gas bearing and four are wet within the Albian age depth interval of 2800m to 3500m. Six lithofacies (A1, A2, A3, A4, A5 and A6) were grouped according to textural and structural features and grain size from the key wells (OP1, OP2 and OP3). Facies A6 was identified as non reservoir rock in terms of reservoir rock quality and facies A1 and A2 were regarded as the best reservoir rock quality. This study identifies the different rock types that comprise reservoir and non reservoirs. Porosity and permeability are the key parameters for identifying the rock types and reservoir characterization. / South Africa

Masters of Science / The Bredasdorp basin is situated off the south coast of the Republic of South Africa, southeast of Cape Town and west-south-west of Port Elizabeth. It covers approximately 18,000 sq. km beneath the Indian Ocean along the southern coast of South Africa, which is in the southwest of Mosselbay. Bredasdorp basin contains South Africa’s only oil and gas production facilities and has been the main focus for oil and gas exploration in South Africa. It is one of the largest hydrocarbon producing block in South Africa, rich in gas and oil prone marine source rocks of kimmeridgian to berriasian age. The wells of interest for this study are located within block 9 which is made up of 13 wells but for this study the focus is only on 3 wells, which are well F-01,F-02 and F-03. The goal of this study is to predict as accurately as possible the areas within and around the sandstone reservoir intervals of these wells with abnormal pressure, using well logs and production test data. Abnormal pore pressure which is a major problem for drillers in the oil industry can cause serious drilling incidents and increase greatly drilling non-production time if the abnormal pressures are not predicted accurately before and while drilling. Petrophysics log analysis was done to evaluate the reservoirs. The intervals of the reservoir are the area of interest.Pore pressure gradient, fracture gradient, pore pressure and fracture pressure model were run. Pressures of about 6078.8psi were predicted around the zone of interest in well F-01, 7861 psi for well F-02 and 8330psi for well F-03. Well F-03 was the most pressured of the three wells. Abnormal pressures were identified mostly at zones above and below the area of interest and predicted pressure values were compared to actual pressure values to check for accuracy.

This thesis investigated the shock compression and fragmentation of ge- ological materials with application to blast mining. Two geological materi- als were investigated; Lake Quarry Granite and Gosford Sandstone. Lake Quarry Granite was fully dense, while Gosford Sandstone was porous. The composition and microstructure of the materials were quanti ed and this information was later used in the analysis of their mechanical properties. The elastic sound speeds were measured for each material, from which their elastic moduli were derived. Gosford Sandstone had a reduced sound speed compared to its component minerals, which was analysed using geometric grain models and Hertzian contact theory. The shock Hugoniot of each ma- terial was measured though a series of plate impact experiments using a light gas gun. The experiments focused on the stress region of interest for blast mining, 0 to 12 GPa. The, fully dense, Lake Quarry Granite was found to have a constant shock speed, which agreed with the elastic longitudinal sound speed measured previously. As the material remained elastic, its Hugoniot was shown to be predictable using composite theory and the chemical com- position. The, porous, Gosford Sandstone underwent shock compaction and resulted in large variations in shock speed. The Hugoniot of Gosford Sand- stone was found to remain partially porous, even to high stresses, and was analysed using a P-a shock compaction model. Explosively-driven expanding ring fragmentation experiments were performed on Lake Quarry Granite to observed its fracture response under loading similar to those in blast mining. The experiments established that the fragment size reduced with loading strain rate until it reached the grain size. After this point the fragment size remained constant with increasing strain rate, a phenomenon not previously observed. The rock was found to be dominated by intergranular fracture, so the minimum achievable fragment size was the size of the grains with this failure mechanism.

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The Drakensberg is the highest part of a 1000-km long escarpment that also forms a natural border between South Africa and eastern Lesotho. The uKhahlamba-Drakensberg Park was declared a World Heritage site in 2000 and is globally significant, in particular due to the rock art painted by San hunter-gatherers who inhabited the area from about 8 000 years ago until the late 19th Century. Approximately 30 000 painted images can be found in nearly 600 rock shelters in the area. Rock art heritage in the Drakensberg is unfortunately being lost through a variety of processes, some natural and others resulting from human impacts. Previous research on the weathering of San paintings has focused largely on either monitoring processes causing weathering in rock shelters or investigating rock surfaces that are adjacent to the rock paintings. Recent findings indicate that some of the San art has been painted onto surfaces that were prepared by smoothing the rock surface with a “grinding stone” and coated with a clay (“ground”) layer prior to the application of pigments. This new information may have important implications for rock art conservation as smoothing of a rock surface could significantly modify the physical and chemical characteristics of the surface, thereby influencing the deterioration of the art. In this study two classification systems are developed from data collected in four rock shelters situated in the Park. The first, a Type of Surface Classification System, is developed for the purpose of identifying different types of rock surfaces within rock shelters. The second, a State of Deterioration Classification System, is developed with the purpose of establishing, through visual inspection, how deteriorated the rock art on different types of rock surfaces is. Linkages between the type of surface and the state of deterioration are also explored. Findings show that it is not only possible to determine which surface type a painting has been painted on, but that different rock surface types can deteriorate through different weathering mechanisms and to a different degree. One type of rock surface, acknowledged but not yet recorded, was found amongst the rock art paintings selected for the purpose of this study. More importantly, the alteration of rock surfaces through human action in the past is found to cause rock surfaces to deteriorate either at an accelerated or a retarded rate as opposed to rock paintings that were made on surfaces that have only been altered by natural weathering mechanisms. For example, if a rock surface has only been smoothed with a grinding stone, results show that weathering mechanisms did not deteriorate the surface as quickly as in the case where a clay ground layer has been applied to the rock surface. Different types of rock surfaces deteriorating through different weathering mechanisms (as a result of surface preparation) might have significant implications in terms of rock art conservation as the strategies implemented to conserve rock art should be adapted to consider surface type. In terms of rock art studies aiming to conserve this precious heritage, the two classification systems presented could, therefore, be useful non-destructive tools in assessing rock art deterioration. Copyright / Dissertation (MA)--University of Pretoria, 2011. / Geography, Geoinformatics and Meteorology / MA / Unrestricted