Geology Commons^™

Quantifying Tekeze River Canyon Incision On The Ethiopian Plateau From Low-Temperature Apatite Thermochronology, Jacob Thomas Grigsby

Masters Theses & Specialist Projects

The Ethiopian Plateau in East Africa features dynamic topography, deep river incision (~1.5 km), active tectonics, continental rifting, volcanic terrain and ~2 km of plateau uplift. Situated on the northwestern part of the Ethiopian Plateau, the Tekeze River is one of the two major rivers associated with incising and documenting the recent geologic history of the uplifted plateau landscape. The consequential Tekeze River incision into the uplifted Ethiopian Plateau is associated with the arrival and impingement of the Afar mantle plume as evidenced by the presence of thick sheets of Cenozoic flood basalts (~30 Ma). However, the Cenozoic to present-day …

Geochemical Analyses Of Base Metals In Sediments And Stream Water Black Cypress Bayou, Marion County, Texas, Melanie L. Ertons

Undergraduate Research Conference

Black Cypress Bayou is a primary tributary of Caddo Lake watershed in eastern Texas. The watershed is underlain by Eocene-aged strata from the Wilcox and Claiborne groups, which represent transgressive/regressive shoreline fluctuations that deposited interbedded friable sandstones and mudstones. The Wilcox Group is of special interest because it contains lignite coal, which has a direct link to heavy metals in sediment and natural waters. Caddo Lake has been listed on the Texas Commission on Environmental Quality 303(d) list for impairment due to mercury in edible tissue since 1995 and Black Cypress Bayou has been listed for impaired waters due to …

Characterization Of Magma Storage And Dynamics At Akutan, Semisopochnoi, And Okmok Volcanoes From Analytical And Numerical Models Of Geodetic, Seismic, And Petrologic Data, Kimberly Degrandpre

Earth Sciences Theses and Dissertations

Volcanic eruptions can cause significant socioeconomic loss, but a better understanding of the processes and dynamics influencing the evolution of volcanic plumbing systems will advance the development of eruption forecasting models that will ultimately mitigate hazards and risks associated with eruptive events. Geologic and geophysical data must be integrated in 3D, finite- element, multiphysical, numerical models to define the coupled evolution of magmatic and crustal stress regimes in volcanic environments, but in data limited regions this is not always an option. The remote nature of the Aleutian Island Arc restricts ground-based monitoring and sampling efforts, and due to sparse temporal …

Prediction Of Tunnel Wall Convergences For Natm Tunnels Which Are Excavated In Weak-To-Fair-Quality Rock Masses Using Decision-Tree Technique And Rock Mass Strength Parameters, Özgür Satici, Tamer Topal

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Tunnel wall convergences should be predicted before the excavation and should be determined accurately in order to ensure safe and economic tunnel excavation media. For this to be possible, rock mass behaviors in the tunnel should also be estimated prior to excavation. This could be ensured by site investigation studies, numerical models and predictive statistics. In this study, the development of convergences during a tunnel excavation in Turkey, excavated by NATM technique, was evaluated by using statistical prediction techniques for weak-to-fair-quality rock masses. For this aim, actual tunnel wall convergence data and rock mass strength parameters were used. For prediction …

Surface Elevation And Sedimentation Dynamics In The Ganges-Brahmaputra Tidal Delta Plain, Bangladesh: Evidence For Mangrove Adaptation To Human-Induced Tidal Amplification, Edwin J. Bomer, Carol A. Wilson, Richard Hale, Abu Naser Mohsin Hossain, F.M. Arifur Rahman

OES Faculty Publications

In the Ganges-Brahmaputra (G-B) delta, periodic flooding of the land surface during the tidal cycle coupled with enormous sediment delivery during the monsoon promotes sediment accretion and surface elevation gain through time. However, over the past several decades, widespread embankment (“polder”) construction in the GB tidal delta plain has led to numerous environmental disturbances, including channel siltation and tide range amplification. While previous research indicates that rates of sediment accretion are relatively high in the G-B tidal delta plain, it remains unclear if and how surface elevation is maintaining pace with relative sea-level rise (RSLR) in this region. In this …

Distribution And Variability In Sulfur Isotopes Within Paleoproterozoic Metasedimentary Strata Of The Michigamme Formation, Upper Peninsula, Michigan, Beau J. Haag

Masters Theses

In the Upper Peninsula of Michigan, the Paleoproterozoic Michigamme Formation is composed of a thick package of metasedimentary rocks derived from foreland basin sediments which were deposited during the 1.8Ga Penokean Orogeny. These rocks contain significant, but variable amounts of texturally distinct sulfide minerals such as pyrrhotite and pyrite. We report a systematic relationship between δ³⁴S values from sulfide mineral occurrences, and their stratigraphic locations regardless of texture and mineral composition. We suggest the sulfide minerals within the Michigamme Formation have inherited δ³⁴S values from early sedimentarydiagenetic sulfides, therefore preserving primary isotopic signatures. The observed stratigraphic …

Nebraska Statewide Groundwater-Level Monitoring Report 2019, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel

Conservation and Survey Division: Faculty and Staff Publications

The term “groundwater” has come to be all but synonymous with Nebraska. Nearly three-quarters of the total volume of the High Plains Aquifer lies beneath the State. Groundwater maintains our streams, our ecosystems, our people, and our vitally important agricultural economy. Nebraska’s total groundwater resource is vast, yet it is also vulnerable to natural and anthropogenic changes, necessitating a long-term commitment to wise management through informed decision making. Monitoring, studying, and reporting form the essential basis for such management and, ultimately, for meeting the myriad challenges presented by change.

The personnel of the Conservation and Survey Division (CSD) are proud …

Field And Numerical Evaluation Of Nitrogen Transport From Septic Systems In Surfical Aquifer Systems To Charlotte Harbor, Florida, Tanten T. Buszka

Masters Theses

Shallow water tables in coastal surficial aquifers limit effective treatment of septic effluent which can result in excess nutrient loading into nearby surface water bodies. Approximately 45,000 septic systems in Charlotte County, Florida transmit effluent into an under studied surficial aquifer and contribute to harmful algal blooms and outbreaks of E. coli. An undeveloped field site was characterized using standard hydrogeologic methods, including a one-year duration natural gradient tracer test, to obtain representative lithology of the sandy surficial aquifer and estimates of groundwater velocity, flow directions, effective porosity and dispersion. These data were used to support the development of a …

Quantifying Water Content In Olivine From North Carolina Dunites Using Fourier-Transform Infrared Spectroscopy, Thomas Byars

Student Scholars Day Posters

The focus of this study is to quantify the water content in grains of the mineral olivine collected from the Buck Creek Ultramafic Suite–a fragment of ancient ocean crust emplaced into the Appalachian Mountains in North Carolina. Previous work on these samples includes Electron Back Scatter Diffraction (EBSD) analysis. EBSD data can constrain temperature and stress conditions of olivine deformation under different levels of hydration. The water in olivine was analyzed using a Fourier-Transform Infrared Spectroscopy (FTIR) at the North Carolina Museum of Natural Science. The olivine grains are doubly polished in preparation for FTIR analysis. The machine scans the …

Storm-Dominated Diatomite: Transport And Deposition From Micro-Texture, Taylor Kelln

Loma Linda University Electronic Theses, Dissertations & Projects

Unusually thick accumulations of diatomite and diatomaceous mud- and siltstones occur throughout the Mio-Pliocene along the Pacific margin. These extensive micro-fossil assemblages represent an important biostratigraphic resource, record of environmental conditions, and are economically relevant as unconventional reservoirs, sources and seals. Most depositional models for diatomaceous sediments tend to emphasize diatom productivity sufficient to overcome siliciclastic dilution and reflect a low-energy depositional regime with passive settling of diatoms through the water column. However, the diatomaceous sediments of the Pisco Basin, Peru, have been observed in longitudinally bedded, wavy, non-parallel laminated deposits, interpreted as hummocky-swaley cross-stratification. Other outcrop observations include tempestite-like …

Density And Aboriginal Uses Of Wild Tree Species In Milawilila Forest Reserve In Morogoro Region, Tanzania, David Sylvester Kacholi

Tanzania Journal of Science

This study assessed density and local uses of wild tree species in Milawilila forest reserve, Morogoro rural district. A total of six transects were set in the forest for assessing density and diversity of trees. In each transect, three plots of 20 m x 20 m were established and all trees with Diameter at Breast Height (DBH) ≥ 10 cm were identified, counted and DBH recorded in each plot. A semi structured questionnaire was used to obtain data on the use of tree species by the locals. Data were analyzed using Microsoft Excel and Statistical Package for Social Science software. …

Mapping Of The Geological Structures Using Digital Elevation Model (Dem)-Derived Flow Direction: A Case Study Of Rungwe Volcanic Province, Southwest Tanzania, Elisante Elisaimon Mshiu

Tanzania Journal of Science

This study aimed to assess the potentiality of Digital Elevation Model (DEM)-derived flow direction in mapping geologic structures, specifically in areas with thick overburden of soil or volcanic materials such as in the Rungwe Volcanic Province, SW Tanzania. Clustering of flow directions based on trends of structure sets found in the study area was applied and it successfully revealed a large number of geological structures through demarcated tectonic blocks from patterns created by flow directions. Northwest–southwest (NW-SE) and NE-SW- trending lineaments are the dominant structural sets in the area whereas N-S and E-W-trending lineaments constitute the minor sets. Moreover, the …

Vegetation Prior To And During Onset Of East Antarctic Glaciation: High Resolution Palynological Insights From Sabrina Coast, East Antarctica, Meghan L. Duffy

LSU Master's Theses

The Aurora Subglacial Basin (ASB) contains an estimated 3.5 m of global sea-level equivalent ice volume and is primarily drained by the Totten Glacier system, which terminates at the Sabrina Coast, East Antarctica. Thinning and retreating of the Totten Glacier indicate that this region is highly susceptible to oceanographic and atmospheric warming. The paleoclimate reconstruction of these changes, conducted in the context of this MS thesis, will improve understanding of East Antarctic Ice Sheet (EAIS) dynamics in this sensitive system. A recent study used seismic and sediment core data to document a dynamic early evolution of the EAIS in the …

The Role Of Floating Gardens To Alter The Water Quality Of The Chicago River: Chicago, Il, Emmett Andrew Spooner

Theses and Dissertations

The pollution of heavy metals within surface water is a rising global concern. As heavy metals are transported through rivers, they can bioaccumulate through the food web, leading to harmful concentrations within waterways. In urban areas such as the city of Chicago, Illinois, the use of road salts is a concern as elevated concentrations of chloride (Cl–) can reduce surface water quality. Since surface waters can carry heavy metals and Cl– salts over a large distance, methods of in-situ phytoremediation are of growing importance. Through a pilot project, a floating garden system has been installed along a portion of the …

High‐Pressure Carbonaceous Phases As Minerals, Oliver Tschauner

Geoscience Faculty Research

High‐pressure carbonaceous minerals establish a link between one of the most abundant chemical elements and processes that occur at high pressures, either in the interior of the Earth or during shock‐metamorphosis in space or on Earth. Diamonds from the Earth's mantle carry inclusions of carbides, carbonates, methane, and carbon‐dioxide. These inclusions elucidate diamond formation and the carbon recycling in the mantle. This chapter focuses on these inclusion minerals themselves, the means of detection, and the reconstruction of pressure‐temperature conditions of their formation in the mantle.

Spatiotemporal Changes Of Microbial Community Assemblages And Functions In The Subsurface, Madison C. Davis

USF Tampa Graduate Theses and Dissertations

The subsurface hosts diverse microbial community assemblages and functions. These communities play an important role in biogeochemical cycling and groundwater purification. Many physicochemical factors affect microbial communities and can cause short-term or long-term perturbations. Subsurface microbes are susceptible to anthropogenic changes in the environment, which can be caused by nutrient inputs or municipal groundwater extraction. Despite the importance of the subsurface microbiome, these microbial communities are poorly characterized. This dissertation describes the characterization of spatiotemporal drivers of subsurface microbial communities through a variety of techniques that include eDNA analyses, bioinformatics, hydrochemical analyses, stable isotope geochemistry, and multivariate statistics. Three coastal …

Constraining Prograde Metamorphic Paths In Archean High-Grade Garnet-Bearing Lithologies From The Eastern Beartooth Mountains, Montana, Usa, Larry Fisher Cliff-Tuttle Jr

LSU Master's Theses

Prograde metamorphic pressures and temperatures of Archean high-grade garnet-bearing lithologies from the eastern Beartooth Mountains of Montana provide an important constraint on the tectonometamorphic history of this terrane and the early Earth in general. A particularly useful means to approximate prograde metamorphic conditions is examining entrapment conditions of garnet mineral inclusions during garnet growth. Lithologies of the eastern Beartooth Mountains are well-suited to this approach because of the presence of abundant mineral inclusions within garnet porphyroblasts. Consequently, prograde metamorphic pressures and temperatures in the Beartooth Mountains, conditions that have only been broadly constrained previously, can be more accurately determined and …

Critical Knowledge Gaps In The Martian Geological Record: A Rationale For Regional-Scale In Situ Exploration By Rotorcraft Mid-Air Deployment, William Rapin Sorbonne Université, A. Fraeman California Institute Of Technology, B. L. Ehlmann California Institute Of Technology, A. Mittelholz University Of British Columbia, B. Langlais, R. Lillis, V. Sautter, D. Baratoux, V. Payré, Arya Udry, B. Horgan, J. Flahaut, G. Dromart, C. Quantin-Nataf, N. Mangold, S. Maurice, J. T. Keane, J. Bapst

Geoscience Faculty Research

Mars oldest terrains hold the answers to key science questions, yet remain largely unexplored. In situ exploration by mid-air deployed rotorcrafts can uniquely answer these questions in the near future due to their unique ability to access the ancient southern highlands and perform in situ analyses at regional-scale, at breakthrough costs.

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes, Melissa S. Chapot, Alexis K. Ault, Greg Hirth, Robert G. Mcdermott

Geosciences Faculty Publications

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick …

Evaluation Of The Potential Geological And Socioeconomic Impacts Of The Imminent Cascadia Megathrust Earthquake, Matthew Pritchard

Honors Program: Senior Projects (Public)

The Cascadia Subduction Zone on the northwest coast of the United States poses the threat of a devastating megathrust earthquake and subsequent tsunami damaging coastal populations. This paper synthesizes literature to analyze the geologic and socioeconomic effects of this natural disaster, as well as examines the existing warning system infrastructure, and makes recommendations to mitigate the damage. In order to assess the geologic effects of a megathrust earthquake, I investigate the tectonic history, the role of episodic tremor and slip (ETS) in stress buildup, crustal architecture of the subduction zone, and analogous subduction zones such as Chile and Japan. This …