Geology Commons^™

Shear Wave Splitting Analysis Beneath Tien Shan: Geodynamic Implications Of Complex Anisotropy, Solomon Gerra Cherie

Doctoral Dissertations

"In spite of numerous studies, the mechanisms for the crustal shortening, mountain formation and associated tectonism leading to complex or simply seismic anisotropy formation beneath the Tien Shan Orogenic Belt is still debated. The most popular hypotheses suggested for the existence of seismic anisotropy are small-scale mantle convection, regional scale resistive basal shear and APM induced asthenospheric flow. Here, we used shear-wave splitting (SWS) measurements with good azimuthal coverage to provide additional constraints on the various models proposed by previous studies. One of the most effective approaches utilized to constrain convective mantle flow patterns is the splitting of P-to-S converted …

Origin And Stratigraphic Architecture Of The Middle Permian Lower And Upper Quanzijie Low-Order Cycles, Bogda Mountains, Nw China, Jonathan Obrist-Farner

Doctoral Dissertations

"This study is carried out in the Bogda Mountains, NW China, and aims to provide a detailed sedimentary, stratigraphic, environmental, and paleoclimatic reconstruction in the paleo-mid-latitude along the east coast of Pangea. The Middle Permian lower and upper Quanzijie low-order cycles (QZJ LCs) provide a nearly complete sedimentary record in an area were little is known. In the first part of this work, the previously-established QZJ LC is divided into two LCs on the basis of regional stratigraphic correlation and major changes in depositional environments and tectonic and climatic processes. The newly-established lower QZJ LC is mainly composed of meandering …

Seismological Investigation Of The Okavango Rift, Botswana, Youqiang Yu

Doctoral Dissertations

The mechanisms of rifting have been intensively investigated using geological and geophysical techniques beneath mature rift zones. However, current understanding on the earliest stages of rifting is seriously limited. Here we employ recently archived data from 17 broadband seismic stations traversing northern Botswana to conduct the first shear wave splitting and mantle transition zone (MTZ) studies within the Okavango Rift Zone (ORZ). The ORZ is an incipient continental rift situated at the terminal of the southwestern branch of the East African Rift System. The resulting normal MTZ thickness and consistently rift-parallel fast polarizations imply an absence of significant thermal anomalies …

Holocene Sedimentology And Stratigraphy Of Coastal Sediments In An Arid Climate, Al Qahmah, Southern Red Sea, Saudi Arabia, Abdullah Ibrahim Nabhan

Doctoral Dissertations

"Holocene sedimentary deposits in Al Qahmah coast, southern Red Sea, in Saudi Arabia have been accumulated on an arid siliciclastic coast in a rift tectonic setting. This study provides a detail interpretation and analysis of sedimentary facies, stratigraphy, depositional environment, and major geological processes. Two studies have been undertaken. First, petrological study of composition and texture of modern sediments and facies mapping delineate facies distribution and mechanisms of sediment transport and deposition. A unique suite of complex riverine, wave, tidal, wind, and chemical and biological processes affect the composition, texture, and distribution of the facies. Second, the depositional environments of …

Modeling Intrusive Geometries Of A Shallow Crustal Intrusion: New Evidence From Mount Ellsworth, Utah, Nathan Nushart

USF Tampa Graduate Theses and Dissertations

Surface displacements resulting from upper-crustal intrusion of melt are a paramount concern for communities and facilities located in or near active volcanic areas (e.g. Campi Flegrei, Yucca Mtn.). Study of active intrusions such as Campi Flegrei, Italy west of Mt. Vesuvius, is limited to remote observations through geophysical/geodetic procedures. While the surface displacement due to melt emplacement at depth can easily be determined, the geometries and depth of intrusions are often based on simplified assumptions (e.g. spheres and prolate or oblate ellipsoids). These models benefit from data constraining both the geometries of the individual intrusions, and the kinematics and mechanics …

3-D Numerical Simulation Of Carbon Dioxide Injection Into The South Georgia Rift Basin For Geologic Storage, Daniel Eric Taylor Brantley

Theses and Dissertations

This study numerically simulated the injection of supercritical phase CO2 into the South Georgia Rift (SGR) basin to evaluate the feasibility and efficacy of long term geologic storage. The injection simulation modeling was divided into two phases. During phase one of the modeling, very little geologic and reservoir dynamics data was known about the SGR basin. Due to lack of basin data, an equilibrium model was used to estimate the initial hydrostatic pressure, temperature and salinity gradients that represent our study area. For the equilibrium model, the USGS SEAWAT program was used and for the CO2 injection simulation, TOUGH2-ECO2N was …

Complexity In Overmarsh Circulation, Jessica Chassereau Sullivan

Theses and Dissertations

Overmarsh circulation is highly complex with variations in current direction over very short timescales and flowpaths that differ substantially between flood and ebb cycles. Understanding such flow complexities in salt marshes is important because they inherently impact the distribution of sediment, larvae and nutrients throughout the marsh, and hence, the ecogeomorphic feedbacks that control landscape evolution. The purpose this Ph.D. research is to quantitatively evaluate the effects of salt marsh topography on overmarsh circulation in a Georgia salt marsh. This dissertation is comprised of three parts. First, digital elevation models (DEMs) were compared to characterize how well airborne lidar (light …

Proxy Development And Application For Reconstructing The Surface Ocean Carbonate System, Brittney J. Marshall

Theses and Dissertations

Over the last two centuries, human activities have led to an unprecedented rate of carbon input into the atmosphere and oceans resulting in an alarmingly rapid decline in surface ocean pH, a process referred to as ocean acidification (OA). This process is leading to an observed decline in the carbonate ion concentrations ([CO3 2-]) in seawater – an ion that a large number of marine organisms (e.g. corals, foraminifera) utilize to secrete their skeletons and shells. The ability to identify past ocean acidification events using the marine sedimentary record can shed light on future impacts of the modern OA dilemma. …

Lithostratigraphic Investigation And Components Of A Complete Petroleum System Within An Upper Devonian Carbonate-Evaporite Sequence : The Birdbear Formation, Williston Basin, North Dakota, Benjamin L. Engleman

Theses and Dissertations

The Birdbear Formation of the Williston Basin of southwestern North Dakota represents one carbonate-evaporite sequence of the Late Devonian. The formation was deposited during regression on a broad, shallow epeiric shelf and is composed principally of dolomite, limestone and anhydrite. The Birdbear Formation is conformable with the Duperow Formation below and the Three Forks Formation above. The designations of 17 lithofacies form the context for describing hydrocarbon generation, migration and accumulation. Rock-Eval 6 and total organic carbon of 42 samples were used to identify the quality of source rocks present in the formation. Good and excellent source rocks were identified …

Geothermal Regime Of The Williston Basin In North Dakota, Faye N. Ricker

Theses and Dissertations

Understanding the thermal regime of a large intracontinental basin such as the Williston Basin can be enhanced by analysis of the relationships among radiogenic heat production, surface heat flow, formation temperatures, and gravity and magnetic anomaly patterns. Digital processing of the spatial and causal relationships gives insight into the effect of basement heat production on the thermal state of the basement rocks and the overlying sedimentary successions. These relationships provide valuable insight on the radioactive heat contribution to heat flow, heat flow from the lower crust, composition of the upper crust, and the potential for geothermal power generation. The specific …

Reservoir Analysis Of The Birdbear Formation (Devonian) In Northwestern North Dakota, Mitchell V. Sigler

Theses and Dissertations

The Birdbear Formation of northwestern North Dakota is a carbonate-evaporite unit deposited on a rimmed carbonate platform during the Late Devonian. The upper and lower contacts are conformable and the formation has been previously divided into two informal upper and lower members. Analyses of core intervals, thin sections, total organic carbon, and wire line logs have allowed for the identification of three informal units that are divided based on lithologic changes, depositional settings, and reservoir characteristics of the formation. Each unit is identified and mapped across the study area using core to log correlations. The units are recognized and named …

Communication Of Lava Flow Hazards At The San Francisco Volcanic Field, Flagstaff, Arizona, Catherine St. John Carter

USF Tampa Graduate Theses and Dissertations

This thesis examines different methods of communicating volcanic hazards to the population of Flagstaff, Arizona using the results of a recent lava flow hazard assessment of the nearby San Francisco Volcanic Field (SFVF). Harburger (2014) determined that given a lava flow originating in the SFVF, there is a statistical probability that it will inundate the city of Flagstaff or even originate from a vent within the city limits. Based on the recurrence rates for the most recent eruptions (3 x 10-4/year), the probability of lava flow inundation in Flagstaff is 1.1 x 10-5 per year.

This study considers the effects …

Schreibersite: Synthesis, Characterization And Corrosion And Possible Implications For Origin Of Life, Nikita Latesha La Cruz

USF Tampa Graduate Theses and Dissertations

We present study of the synthesis and reactions of an analog of the meteoritic mineral schreibersite with formula (Fe,Ni)3P, believed to be a prebiotic source of reactive phosphorus that may have prompted the formation of phosphorylated biomolecules near the time of the origin of life (Pasek and Lauretta, 2005). The mineral was synthesized by mixing stoichiometric proportions of elemental iron, nickel and phosphorus and heating in a tube furnace at 820°C for approximately 235 hours under argon or under vacuum, a modification of the method of Skála and Drábek (2002). The mineral was characterized using X-ray diffractometry (XRD), X-ray photoelectron …

Nearest Neighbor Foreign Exchange Rate Forecasting With Mahalanobis Distance, Vindya Kumari Pathirana

USF Tampa Graduate Theses and Dissertations

Foreign exchange (FX) rate forecasting has been a challenging area of study in the past. Various linear and nonlinear methods have been used to forecast FX rates. As the currency data are nonlinear and highly correlated, forecasting through nonlinear dynamical systems is becoming more relevant. The nearest neighbor (NN) algorithm is one of the most commonly used nonlinear pattern recognition and forecasting methods that outperforms the available linear forecasting methods for the high frequency foreign exchange data. The basic idea behind the NN is to capture the local behavior of the data by selecting the instances having similar dynamic behavior. …

Ground-Coupled Air Waves: A Seismological Case Study Of The Explosion Quakes Of The 2007 Eruption Of Pavlof Volcano, Alaska, Cassandra Marie Smith

USF Tampa Graduate Theses and Dissertations

An abnormally high number of explosion quakes were noted during the monitoring effort for the 2007 eruption of Pavlof Volcano on the Alaskan Peninsula. In this study we manually counted the explosion quakes from their characteristic ground-coupled air waves. This study makes an effort at better quantifying the number of explosion quakes and how the characteristic ground-coupled air waves are affected by wind direction and wind speed. Additionally this study investigates how the ground coupled air waves might be used in a monitoring or analysis effort by calculating energy release and gas mass release. Over 3.2x10⁴ quakes were recorded. …

Glaciological Applications Of Terrestrial Radar Interferometry, Denis Voytenko

USF Tampa Graduate Theses and Dissertations

Terrestrial Radar Interferometry (TRI) is a relatively new ground-based technique that combines the precision and spatial resolution of satellite interferometry with the temporal resolution of GPS. Although TRI has been applied to a variety of fields including bridge and landslide monitoring, it is ideal for studies of the highly-dynamic terminal zones of marine-terminating glaciers, some of which are known to have variable velocities related to calving and/or ocean-forced melting. My TRI instrument is the Gamma Portable Radar Interferometer, which operates at 17.2 GHz (1.74 cm wavelength), has two receiving antennas for DEM (digital elevation model) generation, and images the scenes …

A Composite Spatial Model Incorporating Groundwater Vulnerability And Environmental Disturbance To Guide Land Management, Johanna L. Kovarik

USF Tampa Graduate Theses and Dissertations

Research has long recognized and studied the dynamics of groundwater processes. More recently, groundwater dependent ecosystems (GDEs) are being recognized for their diversity and vulnerability to anthropogenic impact. Groundwater in karst landscapes presents a distinctive situation where flow through the subsurface often moves rapidly on the scale of days and weeks as opposed to years or millennia in other systems. This distinctive situation of karst systems and their vulnerability to human impacts necessitate an integrated and multifaceted approach for the management of these important resources. However, development of such an approach is complicated by the difficulty of obtaining detailed data …

Compositions, Logratios And Geostatistics: An Application To Iron Ore, Clint Ward

Theses: Doctorates and Masters

Common implementations of geostatistical methods, kriging and simulation, ignore the fact that geochemical data are usually reported in weight percent, sum to a constant, and are thus compositional in nature. The constant sum implies that rescaling has occurred and this can be shown to produce spurious correlations. Compositional geostatistics is an approach developed to ensure that the constant sum constraint is respected in estimation while removing dependencies on the spurious correlations. This study tests the applicability of this method against the commonly implemented ordinary cokriging method. The sample data are production blast cuttings analyses drawn from a producing iron ore …

Consider A Cylindrical Cave: A Physicist's View Of Cave And Karst Science, Matthew D. Covington, Matija Perne

Geosciences Faculty Publications and Presentations

We review the current understanding of the physics of caves and karst. Our review focuses on research that has used simple physically based models to improve understanding of processes that occur in karst. The topics we cover include cave atmosphere dynamics, transport within karst conduits, and models of speleogenesis and related processes. We highlight recent advances in these subjects and attempt to identify promising areas for future work. In our judgment, many of the most intriguing open questions relate to the interactions between these three groups of processes.