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GEOL2022BURDEN8814 GEOL

Using Clinopyroxene Chemistry to Constrain Magma Plumbing Systems in a 1.2 Ga Andesitic to Shoshonitic Volcanic Arc, Barby Formation, Namibia

Type: Graduate
Author(s): Lauren Burden Geological Sciences Richard Hanson Geological Sciences
Advisor(s): Richard Hanson Geological Sciences
Location: Basement, Table 6, Position 2, 1:45-3:45

The 1.2 Ga Barby Formation located in SW Namibia is comprised of basaltic andesites and shoshonites from oblique subduction in a volcanic arc setting. Recent mapping and whole-rock geochemistry within the Barby Formation has been completed by previous TCU graduate students. Clinopyroxenes (CPX) from samples collected during these studies were analyzed using an Electron Microprobe (EMP) at Fayetteville State University, North Carolina. Data collected from CPX phenocrysts corresponds with previous findings that the samples can be divided into two groups. Group 1 samples show an enrichment in rare earth elements (REE) and light rare earth elements (LREE) Th, Zr, La/Yb, Nb, with a smaller Ti anomaly as compared to Group 2 (Lehman, 2019; Orhmundt, 2020). CPX phenocrysts within Group 1 have higher TiO2 wt% concentrations. Differences between the two groups are attributed to different source rock compositions and partial melting (Lehman, 2019; Orhmundt, 2020). Mineral compositions and cation ratios from EPMA data were also used to determine geothermobarometric conditions of the formation’s magma plumbing system. Single-clinopyroxene thermometry and barometry equations from Wang et al. (2021) and Purtika (2008) were utilized in this study. Wang et al. (2021) calculations resulted with average pressures between 1-3 ± 1.5 kbar and average temperatures between 1100-1200 °C. Purtika (2008) calculations resulted with overall higher pressures averaging at 3-5 kbar and slightly hotter temperatures at 1200 ± 50°C. Overall temperatures are higher than what would be expected in the basaltic andesitic system and variations could be due to the low-grade metamorphism the area has experienced that has affected the geochemistry.

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GEOL2022DARGE9900 GEOL

Sinkhole Detection, Mapping, and Characterization Using LiDAR-Derived DEM in WINK, Texas

Type: Graduate
Author(s): Yosef Darge Geological Sciences
Advisor(s): Esayas Gebremichael Geological Sciences
Location: Second Floor, Table 3, Position 1, 11:30-1:30

Subsidence is a downward sinking of earth materials that creates a large or small circular surface, but it may produce linear or irregular failure patterns. The highly dissolved calcium carbonate or evaporite rocks allow acidic rainwater to permeate its strata. Near or underlying rock can easily be dissolved in water and create space and caverns underground, making a sudden catastrophic collapse of the land surface. Highly soluble bedrocks are a widespread geologic phenomenon in the West Texas Permian Basin. The majority of the area has been impacted by the subsurface dissolution gypsum layers, which is a cause of the active sinkhole formation from a few meters to 100 m wide. This geohazard has caused damage on infrastructure and civilian property. It can cause environmental problems when it alters the local hydrology. Sinkhole detection using field surveying is expensive, time-consuming, labor-intensive, and not easily accessible, and it might be potentially dangerous for the surveyor. In this paper, I detect, map, and thus analyze anthropogenic triggering factors of sinkholes in Wink, Texas, using open-source high-resolution LiDAR (Light Detection and Ranging) data. Methods involve Generating Digital Elevation Model (DEM), extracting the depressions from DEM, identifying sinkhole boundary contour, and then converting the delineated sinkhole to a polygon shapefile, analyzing the shape and geometric properties. False alarm sinkhole depression eliminates based on the threshold value. Finally, human-induced factors have been investigated.

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GEOL2022DUPREE18054 GEOL

Morrison Formation

Type: Graduate
Author(s): Preston Dupree Geological Sciences Sam Totz Geological Sciences
Advisor(s): John Holbrook Geological Sciences
Location: Second Floor, Table 4, Position 3, 1:45-3:45

Distributive fluvial systems (DFS) are cited to be one of the most dominant fluvial depositional systems seen in continental basins. This system can now be defined by five common characteristics seen in many continental basins: 1) channels that radiate from an apex; 2) a channel size decrease downstream; 3) an increase in preservation of floodplain deposits relative to downstream deposits; 4) a decrease downstream in channel grain size; 5) a change from amalgamated channel deposits in proximal areas to more separated and smaller channels in distal areas. DFSs have been heavily studied in the Morrison Formation near the Four Corners of the United States, however, they have not been tested in eastern New Mexico. The above set of parameters are tested in the Morrison Formation in East New Mexico against the Salt Wash DFS to see how the two systems compare.
Completing this study will provide quantitative analysis over a potential ancient DFS with the goal of providing a dataset that can be used to compare with other DFSs. Additionally, analyzing an unknown area of the Morrison Formation will ultimately open up studies to be worked on in the future. Correlating the East Morrison Formation DFS with the Colorado Plateau Morrison Formation DFS will bridge the gap for determining similarities and differences between these exposures and set the stage for future studies. Additionally, this work will also help us better understand the wider Morrison basin and facies distributions within.

The Upper Jurassic Morrison Formation has been extensively studied in the Western-Interior United States since it contains economic resources of uranium, vanadium, and some of the most well-preserved dinosaur fossils in the United States. Covering over 450,000 square miles from southern Canada to New Mexico, the Morrison Formation's enormous extent presents a unique opportunity to understand the processes happening on Earth's surface during the Late Jurassic. Studies of the Morrison Formation have primarily focused on areas where there are large concentrations of the aforementioned economic resources within its strata. The geologic community has largely overlooked Morrison Formation outcrops in northeastern New Mexico compared to the exhaustively studied outcrops in and around the Colorado Plateau. The absence of recent studies in the Morrison Formation in northeast New Mexico provides a chance to explore it with a level of detail unobtainable until recently. This study will undergo a detailed architectural analysis of two to three extensive outcrops of the Morrison Formation in northeastern New Mexico. This Study will do detailed bedding and facies diagrams of these outcrops from drone images to constrain fluvial style and fluvial history of these rocks. Studying the Morrison Formation in a high level of detail will, in all likelihood, produce new information on the climate and fluvial morphology of the environment in the Late Jurassic. With a new detailed understanding of this all but forgotten piece of the Morrison Formation, the groundwork will be laid for the potential to correlate this piece of the Morrison Formation with other understudied or non-correlatable pieces elsewhere across its vast depositional extent and to piece this part of the Late Jurassic fluvial story into the larger puzzle.

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GEOL2022GACKSTATTER54549 GEOL

Classification and Petrogenesis of a New Martian Meteorite

Type: Graduate
Author(s): Emily Gackstatter Geological Sciences
Advisor(s): Rhiannon Mayne Environmental Sciences
Location: Basement, Table 2, Position 2, 1:45-3:45

Martian meteorites provide us with a window into the processes occurring during the formation and evolution of the terrestrial planets, such as: accretion and differentiation, emplacement and formation of magmatic rocks, the behavior and content of volatile compounds, and the effects of impact events. Here, we present the initial results from a two-phase study on a presumed Martian meteorite, hereafter referred to as NWA X. First, the 800g main mass of NWA X was imaged prior to cutting using 3D laser scans and photogrammetry to produce 3D models of the meteorite’s exterior, and computed tomography (CT) to provide scans of the interior. The main mass was cut and a 175g end piece was donated to the Monnig Meteorite Collection, along with a 5g chip for scientific analysis. In the second phase of the study, we will characterize NWA X in terms of its texture, modal mineralogy, and mineral chemistry. Results from this study will allow us to confirm if NWA X is of Martian origin and, if so, place it in context within the existing dataset for Martian meteorites.

(Presentation is private)

GEOL2022GOWER58196 GEOL

Reexamining Mesosiderite Classification Schemes

Type: Graduate
Author(s): Ethan Gower Geological Sciences
Advisor(s): Rhiannon Mayne Environmental Sciences
Location: First Floor, Table 5, Position 2, 11:30-1:30

Mesosiderites are a group of stony-iron meteorites that contain roughly equal amounts of core material (metal) and crust (silicates) from one or more asteroid parent body. The core material is predominantly Fe,Ni-metal, with some troilite (FeS), and is found as clasts and/or intimately mixed within the meteorite matrix. Silicate clasts are basaltic or gabbroic in origin, representing different formation depths within the crust, and are predominantly plagioclase and pyroxene. The formation of mesosiderites is not fully understood, but observed features require a three stage process: (1) formation of asteroidal silicate crust; (2) metal-silicate mixing, where molten metal is injected into the solid silicates; (3) deep burial, as reflected by the extremely slow cooling rates of less than 1ºC/My. Mesosiderites are classified by pyroxene content and degree of metamorphism, which focuses only on the silicate phases. That not only ignores half of their mineralogy, but also the third stage of their formational history. Additionally, only 15% of known mesosiderites have been studied in detail. This research aims to 1) investigate five previously understudied and ungrouped mesosiderites and 2) determine if metal within mesosiderites can be used to refine current classification schemes.

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GEOL2022HERNANDEZ5461 GEOL

Mapping Landslide Susceptibility in California State

Type: Graduate
Author(s): Rosbeidy Hernandez Geological Sciences
Advisor(s): Esayas Gebremichael Geological Sciences
Location: Second Floor, Table 3, Position 3, 11:30-1:30

Debris flow is a landslide with a quick velocity of displacement that involves risk and damages to life and property. It can be triggered by periods of intense rain usually on steep slopes. Also, a second triggering factor is the influence of wildfire. Wildfire can increase drastically the probability of this type of landslide because the fire burned the vegetation which helps to stabilize the soil and the slope. The research uses geographical information system (GIS) for the development of mapping landslide susceptibility, with a particular interest in the evaluation of areas vulnerable to debris flow natural hazards that may be triggered after a wildfire, with the effects of intensive periods of precipitation. The method has been applied to Montecito city, which was exposed to a massive mudslide in January 2018. The spatial landslide susceptibility response in this study area is correlated to different factors, such as vegetation, lithology, slope gradient, and distance to streams networks which are considered the control of the probability of incidence of a landslide event in this area. Obtained by using the methodology of the multi-criteria decision evaluation (MCE) model. The results obtained from this study indicate that the GIS-based model is valuable and appropriate for the scale used in this study. The model helped to identify areas that still are affected by the wildfire, which can be vulnerable to a new process of debris flow impacting the population closer to the rivers downhill.

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GEOL2022HERNANDEZ61475 GEOL

Mapping Landslide Susceptibility and Ground Displacement Assessment of Austin City and its Surroundings

Type: Graduate
Author(s): Rosbeidy Hernandez Geological Sciences
Advisor(s): Esayas Gebremichael Geological Sciences
Location: Third Floor, Table 3, Position 2, 1:45-3:45

The city of Austin and its surrounding area is experiencing tremendous growth and expansion as a consequence of fast urban development and population growth. This has led to increased constructions and other anthropogenic alterations of the environment to accommodate the growing population and economy. These activities, coupled with the natural conditions and forcings, have made areas within the metropolis susceptible to the threats of landslides. The present study aims to identify zones in the study area that are susceptible to the threats of slow-moving creep/slow-slide landslide hazards and understand the factors and processes that control the occurrence of these events through an integrated study approach. This includes: (1) generating a landslide susceptibility (LS) map through a combination of the triggering factors including local geology and tectonic features, land use/cover, elevation/slope, and precipitation; (2) detecting active deformation processes that could lead to landslide failure using Interferometric Synthetic Aperture Radar (InSAR) analysis techniques applied on Sentinel-1 SAR datasets (2015 – 2020) and validated through datasets from campaign GPS surveys and permanent stations; and (3) identify the factors and processes that directly or indirectly constrain the occurrence of the phenomenon through spatial analysis of relevant datasets. Our findings show: (1) the main concentration of vertical displacement (-1 to -6 mm/yr) is around the northern region of the study area; (2) zones with a moderate subsidence rate coincide with urbanized areas (up to -2 mm/yr) whereas pockets of high displacement rates (up to -6 mm/yr) are noted on NW parts; (3) most of the areas experiencing subsidence are underlain by the Comanche Series characterized by alternating beds of harder and softer limestones interbedded with beds of marly/clayey layers, and formations of marine marl, sandstone, and carbonaceous shale from the Gulf Series; (4) there is a high spatial correspondence between areas with high subsidence rates and high LS index; and (5) efforts are currently underway to analyze relevant datasets to determine factors and processes that control the occurrence of the hazard.

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GEOL2022ISHIMWE48291 GEOL

Climatic Influence on Shallow Groundwater Quality in Texas

Type: Graduate
Author(s): Benite Ishimwe Geological Sciences
Advisor(s): Harvey Omar Geological Sciences
Location: Third Floor, Table 7, Position 1, 1:45-3:45

Nationally groundwater supplies 30% of the freshwater while within Texas that number increases to 60%. As population increases across the United States, Texas being the 7th fastest-growing state, there is immense pressure on freshwater resources. It is important to monitor the quality of groundwater reservoirs to ensure continuous and sustainable use of these reservoirs for current and future populations.
This study assesses the water quality of all nine major aquifers in Texas, with a focus on investigating the water chemistry change across shallow wells (below 300 feet) in these aquifers. This study used a distributed analysis to extrapolate the pH and Total Dissolved Salts (TDS) distribution across Texas major aquifers and revealed that all the shallow wells exhibit signs of water chemistry change. Decadal analysis of data from the Pre-1960s up to 2016 indicates that the pH of these shallow wells had sudden salinization between 1975-1985, followed by significant acidification from 1985 to 2016, where all aquifers followed this trend with the exception of Carrizo Wilcox in the far East and Hueco Mesilla Bolsons in the far West of Texas. On the other hand, TDS increased consistently statewide.
Added effort will be geared towards finding a correlation between the long-term groundwater chemistry change and the land use/land cover change around the major aquifers of Texas. The results of this project will help to determine the possible origin and causes of the change in groundwater chemistry of shallow aquifers in Texas.

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GEOL2022LEWIS59762 GEOL

Mechanical stratigraphy and fault zone deformation in the Austin Chalk in Ten-Mile Creek, Texas

Type: Graduate
Author(s): Carter Lewis Geological Sciences
Advisor(s): Helge Alsleben Geological Sciences
Location: Third Floor, Table 6, Position 2, 1:45-3:45

The Austin Chalk is a rhythmically bedded sequence of chalk and marl that represents pelagic to hemipelagic carbonate deposition in the ancestral Gulf of Mexico during the Upper Cretaceous. The Austin Chalk differs from traditional chalk deposits due to its relatively high abundance of clay and volcanic ash. Outcrops of the chalk stretch from north-central Texas to west Texas and surface exposures mirror the subsurface trend of the Ouachita orogen. Deformation of the heavily fractured Austin Chalk is caused by the normal faults associated with the Balcones Fault Zone.
Historically, the Austin Chalk has been exploited as a conventional hydrocarbon reservoir produced from natural porosity and permeability without large hydraulic stimulations. More recently, the Austin Chalk has been explored as a combination fractured and unconventional reservoir, relying on natural porosity and permeability combined with induced hydraulic fracturing to generate new fracture permeability to release hydrocarbons trapped in microscopic pores. In addition to its reservoir properties, much of the city of Dallas is built within the outcrop trend of the chalk. Thus, understanding the properties and deformation features of the Austin Chalk is also important to the construction industry in north-central Texas.
Deformation of the Austin Chalk in Ten-Mile Creek is characteristic of normal faulting seen in platform carbonate sequences. Faults are identified by the presence of slickenlines and fault gouge, and are surrounded by a damage zone defined by synthetic faulting, jointing, and folding. Deformation is concentrated near the fault core and decreases with distance from the fault core. Here, we present a structural analysis of Church of the Nazarene section of Ten-Mile Creek. The mechanical properties of stratigraphic units are quantified using a Schmidt hammer. Fracture parameters, such as fracture density and intensity, are quantified using scanline surveys. Additionally, spectral gamma ray measurements are made in the field using the RS-230 spectrometer. Spectral gamma ray properties are combined with fracture parameters to create an integrated structural and petrophysical analysis.

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GEOL2022MCLAIN45560 GEOL

Petrogenetic relationships of the Barker Pass volcanic debris-avalanche deposits in the northern Sierra Nevada, California

Type: Graduate
Author(s): Guthrie McLain Geological Sciences Richard Hanson Geological Sciences
Advisor(s): Richard Hanson Geological Sciences
Location: First Floor, Table 5, Position 1, 1:45-3:45

The Sierra Nevada in California has a rich Cenozoic volcanic history including important arc sequences related to the southern Ancestral Cascades dating as far back as 30 Ma (du Bray et al., 2014). The present study focuses on Pliocene volcanic debris-avalanche deposits in the northern Sierra Nevada that fill paleocanyons west and northwest of Lake Tahoe. The paleocanyons trend west, west-southwest, and west- northwest from an unknown volcanic source to the east (Berkebile, 2003; Harwood et al., 2014). The main objective of this study is to examine petrogenetic relations of the debris-avalanche deposits and obtain isotopic ages for them. Another purpose is to determine if the three debris-avalanche deposits are from the same eruptive event or possibly the result of separate eruptions and multiple source vents. To acquire detailed data for this study, I am using whole-rock chemistry of both major and trace elements, electron microprobe analysis of phenocryst phases, and analysis of melt inclusions for magmatic volatile contents. Isotopic ages will be obtained using 40Ar/39Ar dating. Clinopyroxenes (CPX), orthopyroxenes (OPX), and plagioclase phenocrysts from samples collected have been analyzed using an electron microprobe (EMP) at Fayetteville State University, North Carolina under supervision of Dr. Steven Singletary. Data from these phenocrysts phases will be used to determine geothermobarometric conditions of the parental magma chamber or chambers.

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