(Non-) Recovery Of An Agricultural Stream From Straightening And Dredging, Aras Anderson Mann

Graduate Theses, Dissertations, and Problem Reports

In recent history, natural, meandering streams have been straightened and dredged to reduce flooding. While this practice can be effective in reducing flooding locally, it often results in the degradation of stream water quality and aquatic ecosystems. A straighter channel inherently increases the stream gradient, which could increase flow velocity, shear stress, and potentially downstream sediment yield. Studies have shown that straightened, channelized streams often begin to return to a meandering pattern 35-50 years post-channelization. Yet cross-sectional surveys and air photo analysis of the stream reach in this study, Deckers Creek, indicate little to no observable trend of the stream …

Quantifying Chemical Erosion In The Lithologically-Heterogenous Appalachian Valley And Ridge, Amelia Jayne Zanoni

Graduate Theses, Dissertations, and Problem Reports

Quantifying chemical erosion in the lithologically-heterogenous Appalachian Valley and Ridge

Amelia J. Zanoni

The interplay between physical and chemical erosion is well understood in landscapes underlain by a uniform rock type, but many regions are underlain by a mixture of rock types with varying erosion resistance and solubility. We used measurements of stream-water chemistry to estimate chemical erosion rates in the Appalachian Valley and Ridge, a region where the mechanisms of lithologic control over topography are poorly understood. Newly acquired stream water samples were collected from 51 locations across the research area during the Fall of 2023. The sampled waters …

Bedrock Channel Geometry: Meter To Micron Scale Controls On Fluvial Incision, Nicholas J. Colaianne

Graduate Theses, Dissertations, and Problem Reports

The relative resistance of various rock types to incisional processes vary widely and the properties governing bedrock erodibility are poorly understood. Lithologic properties influencing erodibility are the culmination of a rock’s depositional, diagenetic, and exhumation processes. Difficulty identifying a convenient physical proxy for erodibility suggests examining evidence of these processes holistically may offer insight into the role of each in setting a rock’s resistance to incisional forces. In this study we use measured channel geometries along a short stretch of the Dry Fork, WV hosting three distinct lithologic settings to infer relative erodibility against measured and observed fluvial, lithologic, and …

Inverting Passive Margin Stratigraphy For Marine Sediment Transport Dynamics Over Geologic Time, Charles Shobe, Jean Braun, Xiaoping Yuan, Benjamin Campforts, Boris Gailleton, Guillaume Baby, François Guillocheau, Cécile Robin

Faculty & Staff Scholarship

Passive margin stratigraphy contains time-integrated records of landscapes that have long since vanished. Quantitatively reading the stratigraphic record using coupled landscape evolution and stratigraphic forward models (SFMs) is a promising approach to extracting information about landscape history. However, there is no consensus about the optimal form of simple SFMs because there has been a lack of direct tests against observed stratigraphy in well-constrained test cases. Specifically, the extent to which SFM behaviour over geologic space and timescales should be governed by local (downslope sediment flux depends only on local slope) versus nonlocal (sediment flux depends on factors other than local …

The Art Of Landslides: How Stochastic Mass Wasting Shapes Topography And Influences Landscape Dynamics, Benjamin Campforts, Charles Shobe, Irina Overeem, Gregory Tucker

Faculty & Staff Scholarship

Bedrock landslides shape topography and mobilize large volumes of sediment. Yet, interactions between landslide-produced sediment and fluvial systems that together govern large-scale landscape evolution are not well understood. To explain morphological patterns observed in steep, landslide-prone terrain, we explicitly model stochastic landsliding and associated sediment dynamics. The model accounts for several common landscape features such as slope frequency distributions, which include values in excess of regional stability limits, quasi-planar hillslopes decorated with straight, closely spaced channel-like features, and accumulation of sediment in valley networks rather than on hillslopes. Stochastic landsliding strongly affects the magnitude and timing of sediment supply to …

Thickness Of Fluvial Deposits Records Climate Oscillations, Xiaoping Yuan, Laure Guerit, Jean Braun, Delphine Rouby, Charles Shobe

Faculty & Staff Scholarship

Fluvial deposits offer Earth’s best-preserved geomorphic record of past climate change over geological timescales. However, quantitatively extracting this information remains challenging in part due to the complexity of erosion, sediment transport and deposition processes and how each of them responds to climate. Furthermore, sedimentary basins have the potential to temporarily store sediments, and rivers subsequently rework those sediments. This may introduce time lags into sedimentary signals and obscure any direct correlation with climate forcing. Here, using a numerical model that combines all three processes—and a new analytical solution—we show that the thickness of fluvial deposits at the outlet of a …

Boulders As A Lithologic Control On River And Landscape Response To Tectonic Forcing At The Mendocino Triple Junction, Charles Shobe, Georgina Bennett, Gregory Tucker, Kevin Roback, Scott Miller, Joshua Roering

Faculty & Staff Scholarship

Constraining Earth’s sediment mass balance over geologic time requires a quantitative understanding of how landscapes respond to transient tectonic perturbations. However, the mechanisms by which bedrock lithology governs landscape response remain poorly understood. Rock type influences the size of sediment delivered to river channels, which controls how efficiently rivers respond to tectonic forcing. The Mendocino triple junction region of northern California, USA, is one landscape in which large boulders, delivered by hillslope failures to channels, may alter the pace of landscape response to a pulse of rock uplift. Boulders frequently delivered by earthflows in one lithology, the Franciscan mélange, have …

Mapping Surficial Geology In The New River Gorge National River And Bluestone National Scenic River, West Virginia, Using Lidar-Derived Digital Elevation Data, Marla K. Denicola

Graduate Theses, Dissertations, and Problem Reports

The purpose of this thesis was to determine if the surficial geology of Bluestone National Scenic River (BLUE) and New River Gorge National River (NERI), two areas of similar geology, can be mapped using visual interpretation methods applied to digital elevation models (DEMs) derived from light detection and ranging (LiDAR) data. Surficial geology in BLUE was field mapped using GPS, following definitions and characterizations for surficial geology units established with the guidance of Dr. J. Steven Kite. A 2m x 2m LiDAR-derived DEM was used for BLUE and most of NERI using US Army Corps of Engineers (USCOE) LiDAR data, …

First Description Of Subglacial Megalineations From The Late Paleozoic Ice Age In Southern Africa., Graham Dm Andrews, Andrew T. Mcgrady, Shannon M. Maynard

Faculty & Staff Scholarship

We identify late Paleozoic ice age (LPIA) subglacial megalineations from field and geospatial imagery of the Twyfelfontein area of northern Namibia, and present the results of a geomorphometric analysis of those data. Asymmetric 0.1–1.5 km-long megawhalebacks indicate a paleo-ice flow to the northwest. We infer that an ice stream draining the LPIA Kaokoveld ice sheet existed within the proto-Huab River valley and that was comparable to ice streams in modern Antarctica. Recognition of a paleo-ice stream in northern Namibia supports interpretations of glaciogenic sedimentary successions (Itararé Group) in southern Brazil that suggest the presence of major, terrestrial glacial outlet systems …

Petrology Of The Upper Marietta And Hundred Sandstones In Southeastern Ohio, Wayne Dudley Martin

Graduate Theses, Dissertations, and Problem Reports

A petrographic study was made of two Lower Permian (Dunkard Series) sandstones in southeastern Ohio. The sandstone members with which the investigation was concerned are the Upper Marietta sandstone and the Hundred sandstone. The study was made in order to determine the origin of the sandstones and the practicability of applying geologic methods to the grindstone industry. The results of the study indicate that although some of the constituents of these sandstones were derived from igneous and sedimentary source rocks, a relatively large amount of material was derived from metamorphic rocks. The detritus was transported from the east and deposited …