Geological Sciences electronic theses and dissertations (MU)
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The items in this collection are the theses and dissertations written by students of the Department of Geological Sciences. Some items may be viewed only by members of the University of Missouri System and/or University of Missouri-Columbia. Click on one of the browse buttons above for a complete listing of the works.
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Item Mesocopic and geomorphic analysis assessment of cenozoic deformation in the northern Wind River Basin, central Wyoming(University of Missouri--Columbia, 2024) Owens, Ryan Keith; Gomez, Francisco[EMBARGOED UNTIL 12/01/2025] Pregnancy-associated glycoproteins (PAGs) are aspartic proteinases produced by trophoblasts at the fetal-maternal interface. The exact functions of PAGs are unknown. This experiment aims to elucidate PAG function via the ablation of select porcine PAGs in embryos. PAG null embryos were generated via cytidine deaminase base editor. 2 guides targeting homology in 9 of the 12 PAGs were injected into zygotes via microinjection. Subsequent blastocysts were transferred to surrogates and then collected on various days of pregnancy (day 25, day 18). Day 25 yielded no pregnancies. On day 18, the conceptus was present, and PAGKO was confirmed. Histology showed aberrant vascular formation beneath the uterine epithelium. RNAseq analysis showed the down- regulation of several targets related to ECM remodeling. Porcine PAGs appear to affect proper ECM remodeling, though further research will be needed to elucidate the cellular mechanisms of these interactions.Within the northern Wind River Basin, just east of the Boysen Reservoir, the Stagner Creek Fault can be seen exposed within Quaternary gravel formations indicating that tectonic activity has occurred in the recent geologic history of the area. This is relative to the older tectonics of the region produced by Laramide age tectonism and responsible for the deeper tectonic structures such as the Shotgun Butte Thrust Fault. The local environment is sparsely populated. However, a threat to the dam of the Boysen reservoir as well as to the many oil and natural gas wells of the area exists which could have negative implications across the broader region. We used structure from motion (SFM) photography to develop DEMs and scarp profiles that show a 0.36m in the youngest surface that the fault cuts through and corresponds to a 6.3 magnitude quake. New and existing mesoscopic measurements show us that the region has experienced overall contraction. Schmidt hammer sampling helps confirm surface to age relationships in pre-Pinedale age surfaces but is not sensitive enough for post Pinedale age surfaces. The contraction explains the reverse sense of slip on the Stagner Creek Fault. From their relative positions, we also suggest that the Stagner Creek Fault at the surface and the Shotgun Butte Thrust at depth are most likely one in the same. This explains a reactivation of deeper, Laramide age structuresItem Lithospheric structure of the Eastern Anatolia and Caucasus region(University of Missouri--Columbia, 2024) Kocum, Utku; Sandvol, Eric[EMBARGOED UNTIL 12/01/2025] This dissertation investigates the lithospheric structure of the Eastern Anatolia and Caucasus region through an integrated approach employing Two-Plane Wave Tomography (TPWT), Ambient Noise Tomography (ANT), P-wave Receiver Functions, and joint inversion of Receiver Functions with Surface Waves, utilizing new data from the CNET (Caucasus Seismic Network) seismic experiment. The tectonic framework of the Greater Caucasus, Lesser Caucasus, and Eastern Anatolia is predominantly shaped by the continental collision between the northward- moving Arabian Plate and the Eurasian Plate. This ongoing convergence has resulted in the formation of the 1,500-meter-high Eastern Anatolian Plateau, a diffuse deformation zone along the plate boundary, and Mount Elbrus (5,642 meters), the highest mountain in Europe (Philip et al., 1989; Reilinger et al., 2006). Comparisons are drawn to earlier stages of continent--continent collision, such as between the Indian and Eurasian Plates, to enhance our understanding of mountain-building processes in similar tectonic settings (Şengör et al., 1979). The extended TPWT results span from Eastern Anatolia to the Caucasus, providing an updated and refined model compared to Skobeltsyn et al., (2014). Integration of ANT enhances depth resolution at crustal levels, while P-wave receiver functions are utilized to analyze discontinuity structures. The joint inversion of receiver functions with combined ANT and TPWT data yields a high-resolution S-velocity structure from the surface to 100 km depth. Key findings include the identification of a low-velocity zone in Eastern Anatolia across all depths, suggesting asthenospheric upwelling and a thin mantle lid at approximately 100 km depth near the Lithosphere-Asthenosphere Boundary (LAB). Crustal thickness increases from south to north in Eastern Anatolia, with possible crustal thickening observed in the Lesser Caucasus. In the eastern Greater Caucasus, evidence points to a northward-dipping flat ongoing subduction, and a potential new subduction zone may be forming in northern Iran, also oriented northward. The weak, low-velocity crust beneath the eastern Greater Caucasus indicates strain weakening due to flexural loading, which facilitates the formation of thick sedimentary rock layers reaching up to 15-18 km in eastern Georgia, central Azerbaijan and potentially deeper in South Caspian. Crustal thickening in Lesser Caucasus is also evident from joint inversion results.Item Refraction tomography methods applied to shallow seismological imaging(University of Missouri--Columbia, 2024) Ray, Dustin; Sandvol, EricSeismic tomography is widely used to explore the earth's subsurface at a variety of different scales. An important seismological tool to image the relatively shallow part of the subsurface at high resolution is refraction tomography, which uses active sources and observations of the associated travel times rather than passive sources which are used for the deeper parts of the earth. Similar to local and teleseismic travel time tomography this approach attempts to match predicted travel times. I have tested a number of different types of refraction tomography algorithms to learn the benefits and disadvantages of each method. After determining the optimal approach, I have applied the techniques of inverse theory to produce tomographic data gathered from high resolution refraction seismic array in Triplett, Missouri, as well as doing synthetic tests of our study area in order to identify the best refraction tomography tool for use in addressing shallow geophysical imaging problems. The Triplett project examines a potential subsurface fault and its resulting surface expression to determine which tomography algorithms can identify the potential fault throw the best, and to what extent they can synthetically model other potential subsurface structures. The core program used in this study is a Python module package called pyGIMLi (Rücker et al 2017), and a software package based on pyGIMLi referred to as Refrapy (Guedes et al 2022). In this study, I have used refraction tomography to model travel time data collected in Triplett, Missouri, and I have used the final seismic velocity model as a basis for comparison for several simulation tests that help determine the resolution of the tomographic models. I attempt to determine the accuracy of the field data model with resolution tests, and I attempt to determine the resolution of a number of different hypothetical examples of fault throw and geometry. Finally, I list our studies conclusions and important future research directions that can be taken using the framework described in this thesis.Item Numerical modeling of hydrogen sequestration in the northwest bearden hydrocarbon field, Oklahoma (USA)(University of Missouri--Columbia, 2024) Fritz, Veronica; Appold, MartinThe Northwest Bearden hydrocarbon field in east-central Oklahoma is a promising site for underground hydrogen sequestration (UHS). The target UHS reservoir is the Silurian-Devonian age Hunton Limestone located at a depth of approximately 1200 m, which has an average thickness of 35 m, a porosity of 12 percent, and a permeability of 1.03 x 10?15 m2. The Hunton is overlain by the Devonian-Mississippian Woodford Shale, which serves as capping aquitard. In addition to having favorable hydrogen storage properties, the Northwest Bearden field also has considerable well infrastructure from previous oil and gas operations. The goal of this study was to investigate the Northwest Bearden field's UHS potential using numerical modeling. A suite of multi-phase fluid flow models was constructed using the CMG software and well logs obtained from the Oklahoma Geological Survey. The models employed a cyclic pumping schedule in which hydrogen was injected at a rate of 0.8 kg/s for 153 days with variable proportions of methane or nitrogen cushion gas, followed by hydrogen production for 213 days. The results of the models show that injected hydrogen remained within several 100 meters of the wells rather than being broadly dispersed within the Hunton for most relative permeability scenarios. In addition, the Woodford Shale was found to be effective at preventing the upward escape of hydrogen from the Hunton. Nitrogen was found to be a superior cushion gas to methane for enhancing hydrogen production. The models predicted that over the course of 13 years of injection-production, up to 55 percent of the injected hydrogen could be recovered, with increasing efficiency over time. Separate reaction path modeling was conducted using the Geochemist's Workbench software to explore the chemical effects of hydrogen injection on pore water composition and reservoir mineralogy. The model results predict very little mineral precipitation or dissolution, suggesting that the mechanical and hydrologic integrity of the reservoir would be preserved for the injection and production rates used in the models. Pore water composition was also not strongly affected, with the most significant change being a move toward somewhat more reducing conditions. Thus, the results of this study support the suitability of the Northwest Bearden site for UHS.Item Investigation of regional seismic wave attenuation and propagation in the Middle East(University of Missouri--Columbia, 2024) Li, Duyi; Sandvol, Eric A.This dissertation focuses on regional seismic attenuation studies in general but with some emphasis on the Middle East. I have several new approaches that have yielded insight into the behavior of regional seismic phase propagation. The research includes three main projects. Firstly, I developed a method combining the Two Station Method (TSM), Reverse Two Station Method (RTS), and Site Response (SS) measurements to tomographically map the attenuation quality factor Q and relative site responses for Lg and Sn waves. This method has allowed for the integration of three different observations into a single optimal model which is an important step forward in our ability to effectively measure high frequency wave attenuation as well as characterize site amplification. This method was then applied to the Caucasus. The results revealed significant lateral variations in seismic attenuation across the region, with high attenuation in Eastern Anatolia and significant lateral variations in the Lesser and Greater Caucasus regions. Notable impacts from sediments and shallow geology on regional seismic amplitudes were also observed. Secondly, the Double Two Station Method (DTSM) was employed to examine the effects of epicentral distance and source depth on Lg wave attenuation. This method is broadly applicable to regional wave propagation, but we tested this method in the northern Middle East. The findings demonstrated a positive correlation between epicentral distance and Qv measurements for certain regions, suggesting a significant influence of Sn-to-Lg conversion and possibly a deeper sampling by longer paths. The source depth of crustal events showed negligible impact on Lg attenuation. Lastly, a logistic regression model was used to produce the first quantitative Lg blockage map for the Middle East. The model identified widespread blockage in regions with oceanic crust and transition zones, such as the Mediterranean Sea and Caspian Sea. High blockage probabilities were also observed in eastern Anatolia, western Caucasus, and the Zagros fold belts. These works contribute to a better understanding of seismic wave propagation and attenuation in general and especially in the Middle East.