Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed July 14, 2009). Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1953. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [80-81]).

Thesis (Ph.D.) -- Memorial University of Newfoundland. / Typescript. Restricted until October 1991. Bibliography: leaves 495-545. Also available online.

Thesis--University of Cape Town. / Includes bibliographical references.

Karst related sinkholes and subsidence‟s occur on areas underlain by Chuniespoort Group dolomite bedrock in the Gauteng Province. Dolomite land occurs across several South African provinces; however sinkhole and subsidence formation in Gauteng is more well-known than in of the other provinces. Thousands of sinkhole and subsidence events have occurred in the past 60 years. In the past, data on sinkhole and subsidence occurrence has been amassed separately by various consultants, companies and state authorities. There is currently no legal requirement for sinkhole and subsidence events to be reported to a central authority, yet this data is crucial for future assessment of sinkhole hazards and decision making. This study focuses on the dolomitic land areas within four Gauteng municipalities, vulnerable to karst related sinkhole and subsidence formation. Historical as well as current information regarding the sinkhole record for Gauteng was compiled from various sources to develop as comprehensive an inventory of the study area as possible. The importance of sinkhole inventories are reviewed as well as the expediency and efficiency of Geographic Information Systems in data capturing and viewing. Data originates from numerous sources and compiling a comprehensive database presented many challenges, most importantly the large percentage of missing data that could not be retrieved and that the format and quality varies. Only karst related sinkhole, subsidences and crack events prior to 31 December 2011 were considered in this study. The data compiled is only an estimation of the number of events that has occurred in Gauteng. Once all the available sinkhole and subsidence data was collected and compiled, it was organized into multiwave frequency tables and various aspects were analyzed. The data collected, although limited in some cases, is used in statistical analysis to investigate the relationship between the formation of sinkholes and subsidences and underlying geology, size distributions, frequency of events and external influences. Results indicate that to date just over 3000 events (sinkholes, subsidences and ground cracks) are recorded within the study areas, and:  Sinkholes and subsidences are still regularly occurring in areas underlain by dolomite in Gauteng, however based on available data, events in the West Rand and Tshwane appear to show decreasing trend over the last decade.  More events occur in high rainfall months or years (due to increased ingress water entering the ground profile).  The most dominant type of event recorded is sinkholes.  Overall the largest percentage of events has occurred on the chert-rich Monte Christo Formation and Eccles Formation.  Triggering mechanisms were considered for the different areas: on the West Rand most occurrences before 1984 were due to dewatering while after 1984, most are attributed to ingress. The largest percentage of events on the West Rand has occurred in the Oberholzer Groundwater Compartment. In Tshwane almost all occurrences can be attributed to ingress, while in Ekurhuleni, just under a quarter of events were identified as due to dewatering.  When considering sinkhole and subsidence size and depth distributions; the largest percentage of sinkholes in the West Rand (>60%) are large to very large (i.e. from greater than 5m to greater than 15m diameter), the largest percentage of sinkholes in Tshwane (>60%) are medium to large (i.e. from greater than 2m to less than or equal to 15m diameter) and the largest percentage of events in Ekurhuleni (>70%) are small to medium (i.e. less than or equal to 5m diameter).  When considering size distribution on the different formations, it was not possible to determine if certain sizes were more prevalent for specific formations. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Geology / unrestricted

No description available.

Early Ordovician Knox Group carbonates consist of meter-scale dolomite cycles deposited on a passive margin. The meter-scale cycles were deposited under warm, semi-arid conditions, under low amplitude sea level fluctuations on a relatively ice-free earth. The overlying Knox unconformity (~10 m.y. duration), formed by global eustatic sea level fall and tectonic uplift of the subducting margin at the onset of Taconic orogenesis. Middle Ordovician carbonates were deposited on a ramp peripheral to a foredeep in Tennessee. The Middle Ordovician High Bridge Group consists of a 2nd-order supersequence with three 3rd-order sequences (each 30 to 100 m thick), which record a long term change from humid conditions in TST's into more arid conditions during HST's. Peritidal cycles formed under low-amplitude eustatic fluctuations. The late Middle to Late Ordovician carbonates and clastics comprise a 2nd-order supersequence deposited on a ramp peripheral to the Taconic foredeep. The supersequence is composed of four 3rd-order sequences (each 40 to 80 m thick), which contain 11 parasequence sets (2 to 20 m thick). The small sequences are composed of stacked, predominantly subtidal meter-scale cycles (parasequences). Meter-scale subtidal cycles contain facies that suggest they formed under moderate amplitude (20 to 40 m) sea level fluctuations, likely produced by glacio-eustasy. However, peritidal cycles in the HST's indicate they formed under low-amplitude sea level fluctuations, thus suggesting the amplitude of sea level fluctuations decreased during 3rd-order sea level falls. The facies in the supersequence indicate they formed under cool, humid conditions during the 2nd-order TST and became more arid during the 2nd-order HST. The unconformity at the top of the supersequence formed during eustatic sea level drawdown associated with extensive Latest Ordovician glaciation. / Ph. D.

A new paradigm for the formation of calcified skeletons suggests mineralization proceeds through amorphous calcium carbonate (ACC) precursors. The implications of this strategy in carbonate crystallization are widespread, particularly for understanding factors controlling impurity and isotopic signatures in calcium carbonates. The first chapter is a literature review of the biomineralization processes used by two important model organisms: the sea urchin larva and the foraminifera. Sea urchin larvae provide a thoroughly studied example of mineralization by an ACC pathway that is under biological control through regulation of protein chemistry and the local mineralization environment. A review of how foraminifera produce their test structures is also examined to explore the question of how organisms regulate the Mg content in proportion to the temperature their environments of formation. The second chapter demonstrates that acidic biomolecules regulate the composition of ACC for a suite of model carboxylated molecules. The physical basis for the systematic trend in Mg content is related to the ability of the affinity of the biomolecule for binding Ca versus Mg. The third chapter builds on these findings to explore the transformation of Mg-rich ACC precursors to calcites of exceptionally high Mg-contents that could not be produced by classical step-dominated growth processes. The data indicate that these materials are likely a result of a nucleation-dominated pathway. The final, fourth chapter develops Raman spectroscopy-based calibrations for determining Mg contents in ACC. The calibrations are based upon peak position or peak width of the carbonate υ₁ stretch. / Ph. D.

<p> The beach deposits at the head of the Lion's Head Peninsula are described and categorized according to the type, size and morphology of the rocks making up the deposit and their origins. This categorization emerges as a pattern of four zones along the l ength of the beach. </p> <p> The points at each end of the beach, which used to be in a much more defined bay, have been glacially eroded by re-entrants and undercut by postglacial lakes. Shales and dolomite from the escarpment make up this zone's deposits. </p> <p> Zone two is a dolomite cobble beach supplied by the escarpment's erosion from a blockaded late-glacial ice margin and the undercutting of postglacial lakes. </p> <p> Zone three is a mixture of the dolomite from the escarpment, lacustrine sand deposits, and glacial erratics. </p> <p> Zone four is made up of a distinct band of erratics deposited by the ice of the Georgian Bay lobe of the Late Wisconsin Glaciation. The Lion's Head promontory stood resistant to the flow of ice and caused it to deposit these large erratics which are still visible today. </p> / Thesis / Bachelor of Arts (BA)

Master of Science / Department of Geology / Matthew Totten / The Viola Limestone is a prominent petroleum reservoir in the Mid-Continent Region, particularly in Oklahoma and Kansas. Coral Coast Petroleum established production from the Viola Ls. in 2011 in their Stephens Ranch lease in Clark County, south-central Kansas. Development of this lease has been hindered by the unpredictable production rates encountered in each of the subsequent eleven development wells. Infield drilling locations to date were chosen by favorable structural position as determined by 3D seismic. The best reservoir conditions, however, do not necessarily coincide with structural position. It was the purpose of this study to determine whether the ideal porosity and permeability are controlled by depositional environment, diagenetic alterations, or a combination of these factors. Several approaches to solve this question were implemented and utilized, including well log analysis, petrographic inspection of well cuttings and thin sections, and the application of the Scanning Electron Microscope (SEM). An exploration model of the Viola Ls. in this field was developed, where the Viola A and B zones were dolomitized during during marine transgressions by mixing of sea water with other Mg-rich fluids. Reservoir conditions are found where these facies were preserved as paleotopographic highs during a subsequent sea level low-stand. These preserved dolomitized facies correspond to the seismic facies identified by seismic attributes in a 3D seismic study by Vohs (2016).