Geomorphology Commons^™

Comparative Lineament And Geomorphic Analysis Of Chaotic Terrains And Noctis Labyrinthus, Mars, Sarah A. Walton

Electronic Theses and Dissertations

Noctis Labyrinthus (NL) is an extensional trough network connecting the Tharsis rise and Valles Marineris on Mars. Chaotic terrains are a group of polygonally-fractured surface features commonly associated with subsidence due to rapid fluid loss within the subsurface. Polygonal surface patterns are seen at both sites, where geometric topographic highs are bounded by low troughs. Lineaments, topography, and geomorphology of NL and chaotic terrains were analyzed to determine tectonics and fluid influence in the formation and evolution of both sites. NL shows preferential fracture patterns associated with regional extension. Lineaments within chaotic terrains do not show cumulative preferential trends but …

Investigating Mercer's Paradox: A 10be Chronology Of Moraines Deposited During The Last Glaciation At Soda Lake, Wind River Range, Wyoming, U.S.A., Lauren M. Woods

Electronic Theses and Dissertations

Here I use geomorphic mapping and ¹⁰Be surface-exposure dating to address the paradox that lies within the general understanding of the mechanisms driving ice-age climate and glacial cycles. The long-standing and widely accepted Murphy-Milankovitch hypothesis suggests glacial cycles are controlled by the local intensity of summer-time insolation. By this hypothesis, glacier maxima should be achieved at times of low insolation intensity and asynchronously between the polar hemispheres, a pattern which is inconsistent with the glacial geomorphic record. The ¹⁰Be chronology I have constructed of moraines at Soda Lake, Wind River Range, Wyoming, U.S.A. shows nine glacial advances to …

Using An Inventory Of Unstable Slopes To Prioritize Probabilistic Rockfall Modeling And Acid Base Accounting In Great Smoky Mountains National Park, Thomas A. O'Shea

Electronic Theses and Dissertations

An inventory of unstable slopes along transportation corridors and performance modeling are important components of geotechnical asset management in Great Smoky Mountains National Park (GRSM). Hazards and risk were assessed for 285 unstable slopes along 151 miles of roadway. A multi-criteria model was created to select fourteen sites for two-dimensional probabilistic rockfall simulations and Acid Base Accounting (ABA) tests. Simulations indicate that rock material would likely enter the roadway at all fourteen sites. ABA test results indicate that influence of significant acid-producing potential is generally confined to slaty rocks of the Anakeesta Formation and graphitic schist of the Wehutty Formation. …

Comparison Of Land Use And Flowslide Incidence In Palu Valley Following The 2018 Mw 7.5 Palu-Donggala Earthquake, Peta C. Fifield

Electronic Theses and Dissertations

The September 28 Mw 7.5 Palu-Donggala earthquake in Indonesia was the deadliest natural disaster in 2018. Five flowslides on the eastern side of Palu Valley, which were attributed to the substantial majority of deaths and economic losses in the region, occurred due to liquefaction of naturally dry alluvial deposits in gently sloping ground (2 to 6%). The requisite conditions for soil liquefaction are the presence of loose granular sediments and full saturation. Instigation of these catastrophic ground failures were linked to artificial saturation by an unlined agricultural irrigation canal. From a civil engineering perspective, the Palu ground failures on the …

Species Distribution Modeling For Arid Adapted Habitat Specialists In Zion National Park, Sam Driver, Chris M. Schalk, Daniel Unger, David Kulhavy

Electronic Theses and Dissertations

The Arizona toad (Anaxyrus microscaphus) and Jones’ waxy dogbane (Cycladenia humilis var. jonesii) are habitat specialists with historical ranges in the desert southwest and specifically, Zion National Park (ZION). The machine learning method, MaxEnt, constructed species distribution models (SDMs) in ZION for the two study species at 30 m and 900 m spatial resolutions using climate, topographic, and remotely sensed data. Additionally, 900 m forecasting models were constructed to observe the shifts in suitable habitat for the years 2050 and 2070, based off two representative concentration pathway scenarios. Results indicate promising predictive power for both high …

Inter-Annual To Inter-Decadal Spatiotemporal Effects Of Storm And Nourishment Events In North Myrtle Beach, South Carolina, Christina Mary Boyce

Electronic Theses and Dissertations

No abstract provided.

Utilizing The Public On Public Lands: The Application Of Community Science To Monitor And Model Erosion In National Forests, Jacob L. Hansen

Electronic Theses and Dissertations

Unpaved forest roads are adversely affecting coldwater streams through excessive erosion and the subsequent sedimentation of adjacent waterways. To help identify areas of concern, Trout Unlimited (TU) in the Southern Appalachian region developed a Community Science initiative to gather data on sediment sources and stream-road crossings. Volunteers were recruited and trained to monitor road and trail conditions and collect and submit data using a Survey123 application on their cell phones. Analysis of the contributed data reveals statistical connections between drainage type and both erosion level and stream sedimentation. The contributed data were also included as a calibration for the lite …

Characterization Of Surface Karst Using Lidar And Field Traverses, Fort Hood Military Installation, Coryell County, Texas, Heather Jaclyn Dailey

Electronic Theses and Dissertations

The Fort Hood Military Installation is a karst landscape that has been significantly altered for training exercises that include heavy vehicle maneuvers and simulated combat. Traditional karst surveys are often time-consuming and require extensive field analyses to adequately characterize large areas. Bias is given to areas that are most easily accessible and false negatives are common. Previous studies conducted in the eastern and western portion of the base have understated the abundance and spatial distribution of karst, particularly in the western portion.

This study used field traverses and 0.5-meter Light Detection and Ranging (LiDAR) data to characterize surface karst depressions, …

Reconstructing A Centennial-Scale Extreme Paleoflood History Of The Pee Dee River Using Oxbow Lake Sediments, Nicholas William Conway

Electronic Theses and Dissertations

Extreme river floods are the key force shaping floodplain landscape and a major process delivering sediment, pollutants, and nutrients to coasts. These devastating natural hazards pose concerns about potential change of extreme flood occurrence in the face of climate change. However, accurately assessing the impact of anthropogenic climate change and natural climate modes on the intensity and frequency of extreme flooding relies on multi-century discharge records. Unfortunately, instrumental records are relatively short (often <100 years) and overlap with times of dam and reservoir construction. Oxbow lakes, ubiquitous in the floodplains of alluvial rivers, may preserve an archive of extreme flood at centennial timescales as they capture coarser channel sediments transported by intensified river flows. This study has identified signals of extreme floods in oxbow lake sediments and established a timeline of past flooding events to evaluate change(s) in flood hazard near the Pee Dee River (PDR), South Carolina. Laser diffraction grain-size analysis and X-ray computed tomography (CT) scanning were performed on a ~2-m long piston core (SBL2) to identify event layers of extreme floods. CT images reveal high-density laminations and corresponding coarser shifts of grain size are interpreted as flood layers. A robust age-depth model was established for SBL2 using multiple independent age controls (C14, optically stimulated luminescence, Pb210/C137, and historical event tie-points). End-member modelling analysis was performed to identify a coarse component of the grain-size data used as a proxy of extreme flood. A linear relationship between end-member modelling results and measured discharge was established for the last 80 years and applied to the older part of the core yielding peak discharge estimates back to ca. AD 1840. This analysis identifies abrupt shifts in grain size resulting from dam construction, droughts, and local geomorphic changes to the river system. A multidecadal trend in the frequency of extreme floods is present in the PDR system, controlled by Pacific Decadal Oscillation. The most extreme peak annual discharges of the PDR occurred between AD 1870-1900 from the combined interaction of increased tropical cyclone activity with intensified land use for agricultural purposes. Peak annual discharges of the PDR seem to have decreased through time since flood control damming was completed in AD 1962.

Stream Dynamics In The Headwaters Of Post-Glacial Watershed Systems, Brett Gerard

Electronic Theses and Dissertations

This dissertation summarizes research examining watershed processes across Northern New England, with an emphasis on the Central and Coastal regions of Maine. The research presented here focuses on the linkages between watershed geomorphic conditions, climate, and surface flow regimes driving stream channel hydraulic conditions and bed dynamics governing channel geometry. The geologic and human history of the landscape provides the context in which earth surface processes are examined within the dominant physiographic settings in Maine to describe vulnerabilities to climate change. Results are summarized to support the development of sustainability solutions for forecasted watershed management problems by natural resource management …

Depositional Environment And Facies Analyses Of The Owl Mountain Province, Fort Hood Military Installation, Bell And Coryell Counties, Texas, Jacob Meinerts

Electronic Theses and Dissertations

The Owl Mountain Province is a plateaued, karst landscape located in the eastern section of the Fort Hood Military Installation and is characterized by Lower Cretaceous Fredericksburg Group carbonates. The topography is capped by thick sequences of the Edwards limestone; steep scarps and incised valleys along the edges of the plateaus host inter-fingering outcrops of the Edwards and Comanche Peak limestones, and the lower valleys are covered by alluvial sediments and intermittent outcrops of the Walnut Clay. These formations were deposited to the north and west of the main Edwards trend, and are thought to be part of a series …

Three-Dimensional Bedrock Channel Evolution With Smoothed Particle Hydrodynamics, Nick Richmond

Electronic Theses and Dissertations

Bedrock channels are responsible for balancing and communicating tectonic and climatic signals across landscapes, but it is difficult and dangerous to observe and measure the flows responsible for removing weakly-attached blocks of bedrock from the channel boundary. Consequently, quantitative descriptions of the dynamics of bedrock removal are scarce. Detailed numerical simulation of violent flows in three dimensions has been historically challenging due to technological limitations, but advances in computational fluid dynamics aided by high-performance computing have made it practical to generate approximate solutions to the governing equations of fluid dynamics. From these numerical solutions we gain detailed knowledge of the …

A Glacial History Of Roberts Massif, Central Transantarctic Mountains, Antarctica, Using Cosmogenic 3he, 10be, And 21ne Surface Exposure Ages, Alexandra M. Balter

Electronic Theses and Dissertations

Ice-free areas at high elevation in the central Transantarctic Mountains preserve moraines and drift deposits that delineate the former thickness and extent of the East Antarctic Ice Sheet (EAIS); cosmogenic exposure ages on these features indicate when the ice sheet was as or more extensive than today. Approximately 30 existing cosmogenic-nuclide exposure ages from scattered locations within these deposits suggest that some moraines and drift sheets are at least 5 Ma old. Those ages imply that the age range of these deposits may span warm periods during the Miocene and Pliocene, during which the EAIS is hypothesized to have been …

Utilizing Ground-Penetrating Radar In The Delineation And Cultural Resource Management Of Eroding Maine Coastal Shell Middens, Jacquelynn F. Miller

Electronic Theses and Dissertations

Shell middens along the Maine coast archive up to 5000 years of cultural and climatic change, but the record is continually and rapidly lost to the sea through climate-driven coastal erosion and sea-level rise. These sites were constructed by the ancestors of Maine Tribes, and are composed of centimeters to meters of clam (Mya arenaria) and/or oyster (Crassostrea virginica) shells, other faunal remains, and cultural materials. Shell middens record human interaction with the environment and early coastal occupation and adaptation. The faunal remains reflect paleoenvironmental conditions and the distribution of extinct and extant forage-species along the western Gulf of Maine. …

Geostatistical Analysis Of Potential Sinkhole Risk: Examining Spatial And Temporal Climate Relationships In Tennessee And Florida, Kimberly Blazzard

Electronic Theses and Dissertations

Sinkholes are a significant hazard for the southeastern United States. Although differences in climate are known to affect karst environments differently, quantitative analyses correlating sinkhole formation with climate variables is lacking. A temporal linear regression for Florida sinkholes and two modeled regressions for Tennessee sinkholes were produced: a general linearized logistic regression and a MaxEnt derived species distribution model. Temporal results showed highly significant correlations with precipitation, teleconnection patterns, temperature, and CO₂, while spatial results showed highly significant correlations with precipitation, wind speed, solar radiation, and maximum temperature. Regression results indicated that some sinkhole formation variability could be …

Glacial History Of The Tsagaan Gol- Potanin Glacier Valley, Altai Mountains, Mongolia, Mariah J. Radue

Electronic Theses and Dissertations

The last glacial termination (~19-11 ka) marks the end of the last ice age and the transition to modern interglacial conditions. The mechanisms that triggered deglaciation are unresolved. Various hypotheses for deglacial warming involve changes in Earth’s orbit, an 80-ppm increase in atmospheric CO­₂, a ‘bipolar seesaw’ in oceanic-heat redistribution, and shifting wind belts. Here, I present a ¹⁰Be surface-exposure chronology for a system of glacial landforms in the Tsagaan Gol-Potanin Glacier valley in the Mongolian Altai (49°N, 88°E) to determine the nature of the termination in interior Asia. Located near the center of Earth’s largest continent, …

Regional Stress Regime Study Of East Texas Based On Orientation Of Fractures In The Weches Formation, Cory D. Ellison

Electronic Theses and Dissertations

Fractures in the Weches Formation in a roughly 50 mile radius around Nacogdoches, Texas were documented and analyzed using data obtained at various outcrops. This data was used to infer information about the regional stress regime based on the direction of maximum/minimum horizontal stresses (SHmax / SHmin) that formed the fractures. This is based on the principle that systematic, steeply dipping, mode I joints propagate in the direction of SHmax and normal to the direction of SHmin. Joints in the Weches Formation are typically iron filled and are predominantly opening mode, indicated by crack-seal formation, steep dip (700 – 900) …

Geophysical Delineation Of Megaporosity And Fluid Migration Pathways For Geohazard Characterization Within The Delaware Basin, Culberson County, Texas, Jonathan David Woodard

Electronic Theses and Dissertations

ABSTRACT

Differential dissolution of gypsum karst within the Delaware Basin poses a significant threat to infrastructure that society depends on. The study area is located in Culberson County, Texas and traverses a distance of approximately 54 kilometers along RM 652 within the Gypsum Plain which is situated on the northern margin of the Chihuahua Desert and includes outcrops of Castile and Rustler strata that host karst geohazards. Regions of karst geohazard potential have been physically surveyed proximal to the study area in evaporites throughout the Castile Formation outcrop; minimal hazards, in comparison to the Castile Formation, have been documented in …

Gravitational Study Of The Hastings Salt Dome And Associated Faults In Brazoria And Galveston Counties,Texas, Francis C. Okocha

Electronic Theses and Dissertations

Salt domes are important geological structures because they are potential major hydrocarbon traps and have a profound effect on overlying strata in the subsurface. Over five hundred salt domes have been located on the United States Gulf Coast region, including the Hastings Salt Dome. Hastings Oil Field is located about 40.2 km (25 miles) southeast of Houston, Texas. The Hasting oil field was discovered in 1934 and it was considered the largest oil reserve on the Gulf Coast. Its peak production of 75,000 BOPD (barrels of oil per day) was recorded in 1977 and it had a cumulative production of …

The Tuscaloosa Marine Shale: Geologic History, Depositional Analysis, And Exploration Potential, Jessica D. Pair

Electronic Theses and Dissertations

The Tuscaloosa Marine Shale (TMS) was deposited across southern Louisiana and Mississippi during the Upper Cretaceous. The study focuses on a core region containing vast deposits of Cretaceous-aged sediments that have economic importance for oil and gas exploration. This region has been conventionally drilled for decades, focusing on the recovery of the Cretaceous hydrocarbons. Explorers within this region had traditionally targeted the massive sand units of the Lower and Upper Tuscaloosa Group while neglecting the middle Tuscaloosa Marine Shale unit. With the onset of unconventional drilling technology, new explorers to the region have begun to delineate the Tuscaloosa Marine Shale’s …

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …

Shortnose Sturgeon (Acipenser Brevirostrum) Spawning Potential In The Penobscot River, Maine: Considering Dam Removals And Emerging Threats, Catherine Johnston

Electronic Theses and Dissertations

Dam removals from the Penobscot River in Maine restored access to freshwater habitat critical for the life cycle of endangered shortnose sturgeon. Prior to the dam removals, shortnose sturgeon spawning activity had not been documented. Instead, evidence suggested that individuals emigrated from the Penobscot River to spawn in the Kennebec complex, 140 km away. A central question of this thesis was whether spawning activity would commence in the first two years following dam removal. Consistent with pre-dam removal movement patterns determined using acoustic telemetry, the majority (78%) of tagged individuals emigrated from the Penobscot River at some point over the …

Sediment Accumulations Patterns In The Damariscotta River Estuary, Emily A. Chandler

Electronic Theses and Dissertations

The tidally dominated Damariscotta River estuary is located on the south-central Maine coast. The elongate, north-south orientation of the estuary is characteristic of the indented shoreline in this region and a consequence of the bedrock structural framework, comprised of Paleozoic high-grade metasedimentary rocks. Pegmatite sills form bedrock constriction points that divide the estuary into seven distinct basins. The narrow, bending geometry and sill and basin morphology impact the distribution of sediment within the estuary and the hydrodynamics of the system. This study employs multibeam bathymetry surveys, sediment grab samples and radionuclide analysis (²¹⁰Pb and ¹³⁷Cs) of sediment …

The Stratigraphic Position Of Fossil Vertebrates From The Pojoaque Member Of The Tesuque Formation (Middle Miocene, Late Barstovian) Near Española, New Mexico, Garrett R. Williamson

Electronic Theses and Dissertations

The stratigraphy of the Pojoaque Member of the Tesuque Formation near Española, NM is not well understood. This region, during the Middle Miocene, represented a dynamic alluvial fan-fluvial-lacustrine environment within the Española Basin while the Rio Grande Rift was active. Cavazza (1986) identified two paleodrainage systems (lithosome A, basin-margin facies and B, basin-floor facies) by means of sandstone and conglomerate petrology, paleocurrent, and sedimentary facies analyses. After x-ray diffraction analyses of claystones within lithosome B, mordenite was discovered, which is a zeolite mineral commonly found within volcanic rocks. This is significant because the presence of mordenite confirms Cavazza’s (1986) conclusion …

Investigating Coastal Erosion Variability And Framework Geology Influence Along The Grand Strand, South Carolina, Aundrea Marie Dolan

Electronic Theses and Dissertations

Increasing erosional pressures along coastal systems require a better understanding of the mechanisms of natural and human-induced alterations. This is especially important in sediment-starved coastal systems where the effects from geologic framework may exert a disproportionate influence on shoreline behavior. Existing studies into geologic framework and shoreline variability are comprehensive and well documented; yet analysis into the spatial relationships between shoreline variability, lower shoreface morphodynamics, and framework in South Carolina is limited. The Grand Strand region of South Carolina has an extensive set of geophysical data, such as CHIRP seismic, sidescan sonar, borehole logs, and inner shelf cores. In addition, …

Assessing Shoreline Change And Vegetation Cover Adjacent To Back-Barrier Shoreline Stabilization Structures In Georgia Estuaries, Katherine R. Wakefield

Electronic Theses and Dissertations

Anthropogenic stabilization of erosional shorelines by hard-armoring structures is used for protection of property, especially if buildings, historical monuments, cultural resources, or other infrastructure are present. The post-installation effects of shoreline stabilization structures on adjacent shorelines in the back-barrier marshes of coastal Georgia are a concern, and interest in living shorelines as erosion control devices has increased because of their use of natural materials and vegetation. AMBUR shoreline analysis software was used to calculate pre-and post-installation shoreline change rates of shorelines adjacent to riprap and bulkhead structures. There was no significant difference between the post-installation shoreline change rates of the …

Topographic Signatures Of Geodynamics, Samuel G. Roy

Electronic Theses and Dissertations

The surface of the Earth retains an imperfect memory of the diverse geodynamic, climatic, and surface transport processes that cooperatively drive the evolution of Earth. In this thesis I explore the potential of using topographic analysis and landscape evolution models to unlock past and/or present evidence for geodynamic activity. I explore the potential isolated effects of geodynamics on landscape evolution, particularly focusing on two byproducts of tectonic strain: rock displacement and damage. Field evidence supports a strong correlation between rock damage and erodibility, and a numerical sensitivity analysis supports the hypothesis that an order of magnitude weakening in rock, well …

Linking Water Quality And Beach Morphodynamics In A Heavily Impacted Tidal Creek In Myrtle Beach, South Carolina, Brittany Lynne Hoffnagle

Electronic Theses and Dissertations

The morphological changes of small tidal creeks, driven by coastal processes, can pose risks to infrastructure and engineered coastlines and often rely on dredging to maintain them. These changes along the beachface can negatively affect the health of associated estuaries where open exchange between the ocean and creek basins is vital. This study used Real Time Kinematic-Differential Global Positioning System equipment to survey a small tidal creek in Myrtle Beach, South Carolina that often experiences migration to the south and requires dredging to maintain an open exchange between the ocean and the estuary. In order to understand the relationships between …

Thermal And Mechanical Effects Of A Shallow Asthenosphere In The Acadian Orogen: An Investigation Through Numerical Modeling, Lucy E. Brown

Electronic Theses and Dissertations

A high-temperature region associated with Acadian deformation extends 200 km through north-central New England. The scale of this heat source is investigated in order to better understand the rheology and mechanics of deforming orogens. In central Maine, on the boundary of the high-temperature region, isograds in pelitic rocks are normal to the accretionary structures and record a steep northeast-southwest thermal gradient. The isogradic sequence, geobarometry, and the mineral assemblages indicate low-pressure, high-temperature metamorphism, moderately low pressures of 3 kbar, and temperatures ranging from 600º to 450ºC over a 10 km region. The spacing between these isograds and the temperature at …

Relationships Between Stream Geomorphology And Fish Community Structure And Diversity In Maine, Emily Gaenzle

Electronic Theses and Dissertations

Predicting patterns in species distribution and abundance for resource management and conservation is a major focus of applied ecology. The primary objective of this study was to determine if there is a predictable relationship between stream geomorphology and fish community structure, native species richness, and native salmonid abundance in Maine. Specifically, I examined relationships between fish assemblages and geomorphic stream types, as delineated by the Rosgen classification system (Rosgen 1996). Fifty-three stream reaches in Maine were classified, and fish communities within the reaches were characterized using backpack electrofishing. Species richness was lowest in A-type streams (i.e., steep, entrenched, confined), which …