Geology Commons^™

Mantle Flow And Lithosphere-Asthenosphere Coupling Beneath The Southwestern Edge Of The North American Craton: Constraints From Shear-Wave Splitting Measurements, Hesham A. Refayee

Doctoral Dissertations

"High-quality broadband seismic data recorded by the USArray and other stations in the southwestern United States provide a unique opportunity to test different models of anisotropy-forming mechanisms in the vicinity of a cratonic edge. Systematic spatial variations of anisotropic characteristics are revealed by 3027 pairs of splitting parameters measured at 547 broadband seismic stations. The western and southern edges of the North American craton show edge-parallel fast directions with larger-than-normal splitting times, and the continental interior is characterized by smaller splitting times spatially consistent fast directions that are mostly parallel to the absolute plate motion direction of North America. Except …

Plate Kinematics Of The Afro-Arabian Rift System With An Emphasis On The Afar Depression, Helen Carrie Bottenberg

Doctoral Dissertations

This work utilizes the Four-Dimensional Plates (4DPlates) software, and Differential Interferometric Synthetic Aperture Radar (DInSAR) to examine plate-scale, regional-scale and local-scale kinematics of the Afro-Arabian Rift System with emphasis on the Afar Depression in Ethiopia. First, the 4DPlates is used to restore the Red Sea, the Gulf of Aden, the Afar Depression and the Main Ethiopian Rift to development of a new model that adopts two poles of rotation for Arabia. Second, the 4DPlates is used to model regional-scale and local-scale kinematics within the Afar Depression. Most plate reconstruction models of the Afro-Arabian Rift System relies on considering the Afar …

Assessment Of Corrosion Potential Of Coarse Backfill Aggregates For Mechanically Stabilized Earth Walls, Anita Thapalia, David M. Borrok, Soheil Nazarian, Jose Garibay

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The service life of mechanically stabilized earth walls depends on the rate of corrosion of the metallic reinforcements used in their construction. The assessment of corrosion potential requires an accurate evaluation of pH, resistivity, and sulfate and chloride concentrations of aqueous solutions in contact with the surrounding aggregate. Highway agencies tend to use larger aggregates that contain only a small amount of fine material (passing the Number 40 sieve) in the backfill. Evaluation of the electrochemical parameters of coarse aggregates is challenging because traditional evaluation methods call for the use of fine material. In this study, the suitability of traditional …

Surfactant Induced Reservoir Wettability Alteration: Recent Theoretical And Experimental Advances In Enhanced Oil Recovery, Yefei Wang, Huaimin Xu, Weizhao Yu, Baojun Bai, Xinwang Song, Jichao Zhang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Reservoir wettability plays an important role in various oil recovery processes. The origin and evolution of reservoir wettability were critically reviewed to better understand the complexity of wettability due to interactions in crude oil-brine-rock system, with introduction of different wetting states and their influence on fluid distribution in pore spaces. The effect of wettability on oil recovery of waterflooding was then summarized from past and recent research to emphasize the importance of wettability in oil displacement by brine. The mechanism of wettability alteration by different surfactants in both carbonate and sandstone reservoirs was analyzed, concerning their distinct surface chemistry, and …

Magnetic Susceptibility As A Proxy For Investigating Microbially Mediated Iron Reduction, Farag M. Mewafy, Estella A. Atekwana, D. Dale Werkema, Lee D. Slater, Dimitrios Ntarlagiannis, Andre Revil, Magnus E. Skold, Geoffrey N. Delin

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We investigated magnetic susceptibility (MS) variations in hydrocarbon contaminated sediments. Our objective was to determine if MS can be used as an intrinsic bioremediation indicator due to the activity of iron-reducing bacteria. A contaminated and an uncontaminated core were retrieved from a site contaminated with crude oil near Bemidji, Minnesota and subsampled for MS measurements. The contaminated core revealed enriched MS zones within the hydrocarbon smear zone, which is related to iron-reduction coupled to oxidation of hydrocarbon compounds and the vadose zone, which is coincident with a zone of methane depletion suggesting aerobic or anaerobic oxidation of methane is coupled …

Estimation Of The Depth Of Anisotropy Using Spatial Coherency Of Shear-Wave Splitting Parameters, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Shear-wave splitting (SWS) analyses are essential in understanding the structure and dynamics of the Earth's deep interior. While splitting measurements have excellent horizontal resolution relative to other anisotropy-measuring techniques, their vertical resolution is low due to the steep incidence angle of the seismic phases used by the analyses. Here, using synthetic and real data, we present and test a simple approach to estimate the optimal depth of anisotropy by measuring the spatial coherency of the splitting parameters. The approach searches for the optimal depth by computing a spatial variation factor. Tests using synthetic SWS data produced with varying number of …

Reply To "Comment On 'Counterintuitive Consequence Of Heating In Strongly-Driven Intrinsic Junctions Of Bi₂Sr₂Cacu₂O 8+Δ Mesas'", Cihan Kurter, Lutfi Ozyuzer, Thomas Proslier, John F. Zasadzinski, David G. Hinks, Kenneth E. Gray

Physics Faculty Research & Creative Works

The main criticism raised in the preceding Comment concerns our suggestion that sharp conduction peaks in Bi2Sr₂CaCu₂O _8+δ mesas, along with absent dip-hump features, may, in general, be a result of self-heating. The author points to the variety of experimental configurations, matrix-element effects, and doping dependencies that might allow a diversity of conductance spectra. We argue that numerous mesa studies (with fixed matrix elements) firmly establish the systematic development of sharp conductance peaks with increased self-heating, and thus, the issue of nonuniversality of tunneling characteristics is not relevant. The author mentions a number of studies that …

Crustal Structure And Evolution Beneath The Colorado Plateau And The Southern Basin And Range Province: Results From Receiver Function And Gravity Studies, Lamuail Bashir, Stephen S. Gao, Kelly H. Liu, Kevin Lee Mickus

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Over the past several decades, contrasting models have been proposed for the physical and chemical processes responsible for the uplift and long-term stability of the Colorado Plateau (CP) and crustal thinning beneath the Basin and Range Province (BRP) in the southwestern United States. Here we provide new constraints on the models by modeling gravity anomalies and by systematically analyzing over 15,500 P-to-S receiver functions recorded at 72 USArray and other broadband seismic stations on the southwestern CP and the southern BRP. Our results reveal that the BRP is characterized by a thin crust (28.2 ± 0.5 km), a mean V …

Petrographic Comparison And Contrast Of Fluvial And Deltaic Sandstones, Upper Pennsylvanian Oread Cyclothem, Ne Oklahoma, Jonathan Obrist-Farner, Wan Yang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Upper Pennsylvanian sandstones have been the target in petroleum exploration and production in Kansas and Oklahoma. However, the petrographic characteristics of these sandstones have been rarely reported. A good understanding of the characteristics and depositional environments of those sandstones will help explore the correlative subsurface petroleum reservoirs efficiently.

Seismic Interpretation And Reservoir Characterization Of The Middle Eocene Gialo Formation, Assamoud Field, Sirte Basin, Libya, Abdalla Abdelnabi

Masters Theses

"The Gialo Formation is a major gas producing reservoir in the Assamoud Field, Sirte Basin, Libya. It is called Gialo limestone because it consists of shallow marine limestone. Seismic and well data in conjunction with the results of a previous study were used to delineate the hydrocarbon reservoir of Middle Eocene Gialo Formation of Assamoud Field area located in Eastern part of concession 6, Sirte Basin, Libya. The data include three-dimensional seismic data acquired by Sirte Company in 2009. It covers approximately an area of 150 km² and with more than 10 wells penetrating the reservoir. Seismic data were used …

Crustal Structure And Evolution Beneath The Colorado Plateau And The Southern Basin And Range Province, Lamuail Bashir

Doctoral Dissertations

"Stacking of about 15,500 P-to-S receiver functions recorded at 72 USArray and other broadband seismic stations placed on the Colorado Plateau and the SBRP in Arizona revealed systematic spatial variations in crustal Vp/Vs, crustal thickness and amplitude of P-to-S converted phases. Our results reveal that the BRP is characterized by a thin crust (28.2 ± 0.5 km), a mean Vp/Vs of 1.761 ± 0.014 and a mean amplitude (R) of P - to - S converted wave (relative to that of the direct P wave) of 0.181 ± 0.014 that are similar to a typical continental crust, consistent with the …

Applied Palynology: Multidisciplinary Case Studies From Egypt, Gulf Of Mexico And Usa, Mohamed K. Zobaa

Doctoral Dissertations

"Various applications of palynology have been used to study case studies from four different parts of the world, namely northern Egypt, offshore Gulf of Mexico, eastern Tennessee (USA), and New Orleans, Louisiana (USA). In these case studies, palynomorphs (spores, pollen, dinoflagellate cysts, and algae) have been utilized to define zones of hydrocarbon potential, reconstruct paleoenvironmental and paleoclimatic conditions, constrain the ages of the studied rock sequences, and express its potential as a replacement proxy for some expensive organic geochemical analyses. The ability to detect past hurricane activities and their associated damage to the geologic record is here presented as a …

The Sorption Of Chemical And Nuclear Contaminants From Soil And Water Using Nanosize Particles Of Hydroxyapatite, Chyrene Joseph

Masters Theses

"High surface area (>200 m²/g) crystals composed of nanosize (30-50nm) hydroxyapatite; (Ca₅(PO₄)₃OH) particles are being investigated as an alternative in cleaing [sic] contaminated groundwater and soil by removing toxic wastes and radionuclides. Static batch tests were carried out at 2, 4, 8, 24 and 120 hour time periods by reacting hydroxyapatite with individual solutions prepared with specific elements to evaluate the applicability of hydroxyapatite in removing potential contaminants. Chemical analyses on leachant solutions, leachate solutions, and post-reaction digested solids were conducted by Inductively Coupled Plasma-Mass Spectroscopy to determine the extent of ion removal. Removal of these ions is expected …

Morpho-Tectonic Analysis Of The Tekeze And The Blue Nile Drainage Systems Of Northwestern Ethiopian Plateau, Ethiopia, Elamin Hassan Dai Ismail

Masters Theses

"This study examines the morpho-tectonic evolution of the drainage system in the northwestern Ethiopian plateau by focusing on the Tekeze and the Blue Nile Rivers. The plateau is underlain by Precambrian crystalline rocks, overlain by Mesozoic sedimentary section that is topped with a 1-3 km thick pile of Oligocene-Quaternary volcanic rocks. It is bounded in the east and southeast by the Afar Depression (AD) and the Main Ethiopian Rift (MER). Satellite derived Digital Elevation Models are analyzed using ArcGIS and RiverTools to extract morpho-tectonic parameters of tributaries of the Tekeze and Blue Nile Rivers including Normalized Steepness Index (K_{sn …}

The Origin Of Quartz Glomerocrysts: Insights From The Rhyolite Dike At Medicine Park, Ok, Sedeg Ahmed E. Ahmed

Masters Theses

"The origin of quartz glomerocrysts a distinctive petrographic feature of the rhyolite dike in Medicine Park, Oklahoma, was investigated using transmitted light and cathodoluminescence microscopy to determine if quartz glomerocrysts formed during quartz crystallization or during quartz dissolution. Quartz glomerocrysts are typically comprised of two to six individual phenocrysts of quartz and commonly exhibit subhedral partially embayed crystal forms with very rare euhedral phenocrysts in both glomerocrysts and individual quartz phenocrysts. The size range of the individual quartz phenocrysts are 0.08mm to 1.7mm while the size range is 0.08mm to 3.25mm for quartz glomerocrysts . Cathodoluminescence revealed that individual quartz …

Evaluating The Effectiveness Of Multi-Spectral Remote Sensing Data For Lithological Mapping In Arid Regions: A Quantitative Approach With Examples From The Makkah Neoproterozoic Region, Saudi Arabia, Nawwaf Awad Al Muntshry

Masters Theses

"This work quantitatively evaluates the effectiveness of multi-spectral remote sensing data for geological mapping in arid regions. For this, Landsat Thematic Mapper (TM) data covering part of the Neoproterozoic Arabian Shield around the Makkah region in Saudi Arabia are used. The Makkah region is dominated by a variety of layered and intrusive rocks covered by unconsolidated sediments. The Landsat TM data have six spectral bands in the visible and near infrared (VNIR) and shortwave infrared (SWIR) with thirty meters spatial resolution.

The Optimum Index Factor (OIF) has been computed to determine the best Red-Green-Blue (RGB) band combination emerging from the …

Geological And Geomorphological Evolution Of The Egyptian Nile Between Aswan And Kom Ombo: A Remote Sensing And Field Study Approach, Leslie Lansbery

Masters Theses

"This work uses field and remote sensing studies to examine structural controls of the Egyptian Nile between Aswan and Kom Ombo (referred here to as AKN). This segment of the Egyptian Nile incises through Cretaceous Nubian sandstone and Precambrian crystalline rocks separated by a shallowly-dipping to theN unconformity. It was only 0.8 Ma that the Egyptian Nile connected to the rest of the sub-Sahara Africa drainage system. Prior to this time, the Egyptian Nile evolved independently through 8 phases: Pre-Eonile (Ma), Eonile (6.0-5. 4 Ma), Gulf Phase (5.4-3.3 Ma), Paleonile Phase (3.3-1.8 Ma), Desert Phase (1.8-0.8 Ma), Prenile Phase (0.8-0.4 …

A Detailed Petrographic Analysis Of The Mt. Sheridan Roosevelt Gabbro And Associated Rock Types, Daniel Russell Lasco

Masters Theses

"The Mt. Sheridan Roosevelt Gabbro of the Wichita Mountains igneous province in Southwestern Oklahoma underwent dynamic crystallization, resulting in three distinct gabbro zones with a range of pegmatite morphologies spread throughout. The three zones are informally named the lower, central, and upper zones. The lower zone consists of a quartz and alkali feldspar poor, plagioclase and pyroxene rich, poorly altered, gabbro cumulate. The central zone is comprised of a heavily altered quartz and alkali feldspar rich gabbro with few cumulate textures. The upper zone is mineralogically and texturally identical to the lower zone, distinguished only by its higher elevation. The …

Receiver Function Studies Of Crustal Structure, Composition, And Evolution Beneath The Afar Depression, Ethiopia, Sattam A. Almadani

Doctoral Dissertations

"The dissertation utilizes a set of sophisticated computer programs developed at the Geophysics group at Missouri S&T to characterize crustal properties beneath the Afar Depression in Ethiopia where extensional tectonics dominates. In this study, measurements of crustal thickness (H), crustal mean Vp/Vs [which is related to Poisson's ratio (Σ)], and the sharpness of the Moho (R) were determined using teleseismic data from 18 broadband seismic sensors that we deployed along a profile of 250 km long with a station spacing of ~ 10 km. The stations had been recording continuously for an entire year from December 2009 until December 2010. …

A Geological And Geophysical Study Of The Tendaho Graben In The Afar Depression, Ethiopia: Insights Into Transitional Continental Rifting, David Lee Bridges

Doctoral Dissertations

"A detailed magnetic and gravity study across the Tendaho Graben (the Red Sea propagator within the Afar Depression, Ethiopia) revealed features that can best be interpreted as a continental rift undergoing oceanization. This NW-trending extensional structure is ~50 km wide and it is confined within well-developed NW-trending boarder faults that deform the 2 km thick and ~ 2 Ma basaltic flows of the Afar Stratoids. The age of the basaltic flows becomes progressively younger inward from the boarder faults until it reaches ~30,000 years close to the rift axis. The central part of the Tendaho Graben is characterized by a …

Two New Spline-Based Methods And Real Data Applications: High-Resolution Receiver Function Calculations From Teleseismic Broadband Waveforms And High-Accuracy Practical Potential-Field Integral Transformations, Bingzhu Wang

Doctoral Dissertations

"While receiver function (RF) calculation is fundamentally important and widely used, it is not well solved due to unstable deconvolution. A spline-based RF calculation method was proposed and it is demonstrated that both individual RFs and the stacked RF calculated with the spline method have sharper peaks than those with the water-level spectral division method and the iterative deconvolution method. At the common peaks on the stacked RFs, there are close similarities for all three RF calculation methods. The better calculated RFs with the spline method lead to improved H - K analysis and improved determination of the optimal Moho …

Apparent Weekly And Daily Earthquake Periodicities In The Western United States, And Evolution Of Wadi Kubbania In Egypt, Ali Hadi Atef

Doctoral Dissertations

"The dissertation consists of two separate sections. The first section is on apparent daily and weekly periodicities in earthquake occurrence in the western United State [sic]. Analysis of Apparent Seismicity Rate (ASR) in the western United States confirmed the existence of prominent spectral peaks with a period of 1 and 7 days. The number of recorded earthquakes on Sundays for the duration of 1963-2008 is about 5% higher than that on weekdays, and, more significantly, there is a 9% increase of ASR in the early morning compared with that in the middle of the days. Significant similarities between the spatial …

Geophysics At The Interface: Response Of Geophysical Properties To Solid-Fluid, Fluid-Fluid, And Solid-Solid Interfaces, Rosemary Knight, Laura J. Pyrak-Nolte, Lee D. Slater, Estella A. Atekwana, Anthony L. Endres, Jil T. Geller, David P. Lesmes, Seiji Nakagawa, Andre Revil, Mukul M. Sharma, Christian Straley

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Laboratory studies reveal the sensitivity of measured geophysical properties to solid-fluid, fluid-fluid, and solid-solid interfaces in granular and fractured materials. In granular materials, electrical properties and nuclear magnetic resonance relaxation times exhibit a strong dependence on the size and properties of the solid-fluid interface. The electrical and seismic properties of granular materials and the seismic properties of fractured materials reveal a dependence on the size or geometry of fluid-fluid interfaces. Seismic properties of granular and fractured materials are affected by the effective stress and cementing material at solid-solid interfaces. There have been some recent studies demonstrating the use of field-scale …

Seismic Anisotropy Beneath The Afar Depression And Adjacent Areas: Implications For Mantle Flow, Stephen S. Gao, Kelly H. Liu, Mohammed G. Abdel Salam

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Shear wave splitting is a robust tool to infer the direction and strength of seismic anisotropy in the lithosphere and underlying asthenosphere. Previous shear wave splitting studies in the Afar Depression and adjacent areas concluded that either Precambrian sutures or vertical magmatic dikes are mostly responsible for the observed anisotropy. Here we report results of a systematic analysis of teleseismic shear wave splitting using all the available broadband seismic data recorded in the Afar Depression, Main Ethiopian Rift (MER), and Ethiopian Plateau. We found that while the ~450 measurements on the Ethiopian Plateau and in the MER show insignificant azimuthal …

Applied Technologies And Prospects Of Conformance Control Treatments In China, Yuzhang Liu, Baojun Bai, Yefei Wang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

China is the largest user of chemical-based conformance control treatments and a series of technologies have been successfully developed and deployed in recent years. This paper first shows the milestones of development and application of conformance control technologies in China. Then integrated conformance control technologies are reviewed followed by the lessons we have learned, and then a few major specific conformance control technologies are addressed, including tracer injection and channels explanation, potentiometric testing to identify areal sweep efficiency, Pressure Index (PI) decisionmaking technology to select well candidate, complementary decision-making technology to select well candidate and design application parameters, and major …

Experimental Estimation Of The Gpr Groundwave Sampling Depth, Katherine R. Grote, Taylor Crist, Crystal Nickel

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Monitoring near-surface soil water content is essential for efficient water management and for understanding hydrologic processes in soils. Ground-penetrating radar (GPR) groundwaves are an approach that can be used to monitor the near-surface soil water content, but the efficacy of this technique is currently limited by the uncertainty surrounding the groundwave sampling depth. This research experimentally determines the sampling depth of GPR groundwaves under dry and saturated conditions in a sandy soil. Data were acquired using 250, 500, and 1000 MHz antennas within an experimental tank containing soil layers of contrasting electromagnetic velocities. Results show that the groundwave sampling depth …

Sensitivity Of Geoelectrical Measurements To The Presence Of Bacteria In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana, Silvia Rossbach, D. Dale Werkema

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We investigated the sensitivity of low-frequency electrical measurements (0.1-1000 Hz) to (1) microbial cell density, (2) live and dead cells, and (3) microbial attachment onto mineral surfaces of clean quartz sands and iron oxide-coated sands. Three strains of Pseudomonas aeruginosa PAO1 (wild type and rhlA and pilA mutant) with different motility and attachment properties were used. Varying concentrations of both live and dead cells of P. aeruginosa wild type in sand columns showed no effect on the real conductivity component (σ′). However, the imaginary conductivity component (σ″) increased linearly with increasing concentrations of live cells in sand columns, whereas minimal …

Characterization Of Soil Water Content Variability And Soil Texture Using Gpr Groundwave Techniques, Katherine R. Grote, Cale T. Anger, Bridget Kelly, Susan Sharpless Hubbard, Yoram N. Rubin

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Accurate characterization of near-surface soil water content is vital for guiding agricultural management decisions and for reducing the potential negative environmental impacts of agriculture. Characterizing the near-surface soil water content can be difficult, as this parameter is often both spatially and temporally variable, and obtaining sufficient measurements to describe the heterogeneity can be prohibitively expensive. Understanding the spatial correlation of near-surface soil water content can help optimize data acquisition and improve understanding of the processes controlling soil water content at the field scale. In this study, ground penetrating radar (GPR) methods were used to characterize the spatial correlation of water …

Design Of A Conditioner For Smoothing Wind Turbine Output Power, Murali Bottu, Mariesa Crow, A. Curt Elmore

Electrical and Computer Engineering Faculty Research & Creative Works

As a result of wind speed intermittency, highly variable wind power output can adversely impact local loads. We propose a conditioner to smooth the variable wind power by utilizing the energy of an ultracapacitor. The conditioner is based on a single phase voltage source inverter (VSI) connected between the grid interconnection point and the ultracapacitor. The shunt VSI injects or absorbs active power from the line to smooth the wind power by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a DC-DC converter, which maintains the voltage of the DC …

Spatial Variations Of Crustal Characteristics Beneath The Hoggar Swell, Algeria, Revealed By Systematic Analyses Of Receiver Functions From A Single Seismic Station, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Hoggar swell in Algeria is one of the significant massifs of northwest Africa. The paucity of high-resolution geophysical studies of the crust and mantle beneath the massifs is mostly responsible for the heated debates about the depth of the source region of the Cenozoic volcanism and the closely related uncertainty about the mechanism that formed and maintains the high elevation of the swells. Here we report results from a systematic study of 1386 high-quality receiver functions (RFs) recorded by station TAM, the only permanent broadband seismic station on the Hoggar swell. The resulting crustal thickness is about 34 km …