Geomorphology Commons^™

Size, Timing, And Landscape Impacts Of Glacial Lake Outburst Floods In The Channeled Scabland Of Eastern Washington, Usa, Karin E. Lehnigk

Doctoral Dissertations

Extreme floods have dramatically altered landscapes on Earth and Mars through bedrock erosion, sediment deposition, and canyon formation. The Channeled Scabland of the Columbia Plateau in eastern Washington, USA, is perhaps the most striking example of such a landscape, where outburst floods from an ice-dammed glacial Lake Missoula eroded immense canyons and transported large volumes of sediment during the late Pleistocene. Despite advances in numerical modeling and geochemical exposure dating methods, it has remained a challenge to untangle the complex interactions between floodwater, bedrock, and glacial ice to link the size of a flood with its impact on the landscape. …

Coastal Geomorphic Response To Sea-Level Rise, Storms, And Antecedent Geology: Examples From The Northern Gulf Of Mexico, Clayton Dike

Dissertations

Sea-level rise and tropical cyclone activity are threatening coastlines around the world. Past geologic coastal responses can be used to inform future scenarios. This three-part study examines the response of coastal systems to sea-level rise, storms, sediment supply, and antecedent geology over the past ~ 140 ka.

The first study is of the Bay St. Louis, Mississippi, coastal system along the northern Gulf of Mexico incorporating sediment supply, subsidence, and antecedent topography paired with an examination of geologic response to sea-level fall and rise. I used core and geophysical data that resolve incised valleys and other subsurface deposits from ~ …

Sedimentary Characteristics And Associated Carbon And Nutrients Of Overbank Sediments Deposited During The 2018, 2019, And 2020 Floods In Embanked Floodplains Along The Lower Mississippi River Near Natchez, Mississippi, Rachel Kelk

Master's Theses

The Lower Mississippi River (LMR) experienced major floods in 2018, 2019, and 2020. Sediment deposition in the embanked floodplains during floods represent important storage and sequestration opportunities for carbon and nutrients from ~40% of the continental USA. This research aims to compare depositional thicknesses, organic matter (OM), carbon (C), nitrogen (N), phosphorous (P) concentrations, and grain sizes in floodplain sediments deposited by the combined 2018-19 floods to the 2020 flood along the LMR near Natchez, Mississippi. Greater depositional thicknesses in 2018-19 are best explained by their combined flood durations; the 2019 flood was the longest in recorded history. Slightly higher …

Echoed Sites And The Unknowable Object, Joseph Canizales

MFA in Visual Art

This thesis will discuss the expanded field of sculpture, simulacra, digital technology, and two terms I’ve devised: the unknowable object, and echoed sites. Within these two terms, I’m concerned with the complicated relationship between humans and geology and how we extract material from the ground without reflecting on the geologic history of the site. In echoed sites I create sculptures with and without a geologic site or object, by way of digital technology. These forms display two states paradoxically in balance, where what’s presented leaves more questions than answers. Thus, as part of echoed sites, exists the unknowable object. …

Distribution Of Particulate Organic Carbon – Fluxes And Inventories – In Growth-Faulted Coastal Wetlands, Samuel Joel Whitehead

Theses and Dissertations--Earth and Environmental Sciences

Coastal wetlands along the Northern Gulf of Mexico (NGOMx) are critically important but threatened environments which provide significant and diverse economic, social, and environmental value. These environments are essential components to the global carbon cycle, serving as one of the most efficient terrestrial carbon sinks. Since onset of the Industrial Revolution increasing rates of coastal wetland loss have been documented due to a variety of anthropogenic activities, neotectonic processes, subsidence, and rising sea-levels. This research utilized an array of methods and sedimentological analyses to test the hypothesis that growth-fault induced changes at Earth’s surface affects the delivery to, and storage …

Geomorphic History And Preservation Of Archaeologically Significant Areas In The Hanford Reach Of The Columbia River, Washington State, Benjamin Deans

All Master's Theses

Archaeological sites near rivers may be preserved through burial, altered by exposure, or destroyed through erosion. Preserved because of the unusual needs of the Manhattan Project, the Hanford Reach is the only remaining free-flowing reach of the Columbia River and ideal for research into the geomorphic settings of archaeological sites along this river. The 1894 (742,000 cfs [20,900 m³/s]) and 1948 (690,000 cfs [19,000 m³/s]) floods were the largest in the historical record through the reach, but their relationship with geomorphic change and site preservation are less understood. To understand how floods have preserved and destroyed …

Evaluating The Relationship Between Floodplain Topography And Channel Avulsion: Evidence From The Devonian Catskill Formation, North-Central Pennsylvania, Usa, Molly O'Halloran

Honors Theses

Topographic complexity on floodplains can route flow, control sediment dispersal, and influence channel behavior, but studying floodplain-channel interactions in modern rivers is challenging because of human modifications and the short timescales of observable data. This project assesses the link between different types of floodplain microtopography and avulsion style in the Devonian Catskill Formation, north-central Pennsylvania, where thick stacks of fluvial strata provide a lengthy record of channel-floodplain interaction. Using a combination of field observations and computer modeling, this study identifies sedimentary features indicative of floodplain complexity and analyzes their impact on avulsion style at fourteen Catskill Formation outcrops.

Based on …