Geomorphology Commons^™

Convergence Of Dune Topography Among Multiple Barrier Island Morphologies, Jackie Ann Monge

Theses and Dissertations--Geography

Wave-dominated and mixed tidal and wave energy barrier islands are assumed to have characteristic dune topographies that link to their macroscale form. However, there has been no systematic attempt to describe the linkage between barrier island macroscale form and dune topography. The goal of this thesis was to investigate how dune topographies correspond to a number of barrier island morphologies found along the southeastern U.S. Atlantic coast. Macroscale process-form variables were used to classify 77 islands into seven morphologic clusters. Islands from each cluster were selected and sites characteristic of the range of dune topographies within islands were characterized using …

A Remote Sensing Investigation Of Elevated Sub-Horizontal Topographic Surfaces In The Wichita Mountains, Oklahoma, Liang Xue

Masters Theses

"Multiple elevated horizontal to sub-horizontal topographic surfaces are present in the Wichita Mountains, Oklahoma. Elevated topographic surfaces, developed primarily on granite bedrock with gentle slopes of 0.5 to 7⁰,were investigated using 1) Digital Elevation Models (DEMs) extracted from NAD 27 UTM coordinates, 2) Google Earth imagery, and 3) USGS topographic maps. In the western Wichita Mountains prominent topographic surfaces at elevations of 720 ± 5 m, 685 ± 5 m, and 660 ± 5 m are well preserved on at least four different mountains (e.g., Solder's Peak, King Mt.) and can be correlated with similar surfaces on at least seven …

Determining Hillslope Diffusion Rates In A Boreal Forest: Quaternary Fluvial Terraces In The Nenana River Valley, Central Alaska Range, Laurel Anne Walker

Theses and Dissertations--Earth and Environmental Sciences

The subarctic boreal forest biome is predicted to experience higher magnitudes of warming than other biomes due to climate change. The effects of this warming will be pronounced in areas underlain by discontinuous permafrost where melting permafrost and distinct changes in vegetation patterns are expected. To better understand rates of hillslope diffusion in the boreal forest I have used a geomorphic process modeling approach, using data from a sequence of Quaternary fluvial terraces located in the Nenana River valley of central Alaska. I hypothesized that diffusion rates here would be slower when compared to the mid-latitudes, and faster on north …

Paleoseismic And Structural Characterization Of The Hines Creek Fault: Denali National Park And Preserve, Alaska, Sara E. Federschmidt

Theses and Dissertations--Earth and Environmental Sciences

The Hines Creek fault (HCF) is a Holocene-active fault in central Alaska. Its trace has been mapped several times, but data on the history of fault displacement is scarce. As a major crustal-scale geologic boundary with uncertain Quaternary tectonic activity, it is a priority for more to be known about the activity of this fault to better understand the hazards it presents to the Denali National Park and Preserve and Alaskan infrastructure. This study characterizes the late Quaternary activity of the HCF through surficial geologic mapping and paleoseismic investigations. Mapping revealed a very steep (~84°-88° apparent dip), north dipping fault …

Biomechanical Effects Of Trees And Soil Thickness In The Cumberland Plateau, Michael Shouse

Theses and Dissertations--Geography

Previous research in the Ouachita Mountains, Arkansas suggests that, on relatively thin soils overlying bedrock, individual trees locally thicken the regolith by root penetration into bedrock. However, that work was conducted mainly in areas of strongly dipping and contorted rock, where joints and bedding planes susceptible to root penetration are more common and accessible. This project extended this concept to the Cumberland Plateau, Kentucky, with flat, level-bedded sedimentary rocks. Spatial variability of soil thickness was quantified at three nested spatial scales, and statistical relationships with other potential influences of thickness were examined. In addition, soil depth beneath trees was compared …

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Department of Earth, Environment and Sustainability Faculty Publications

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect analysis …

Architecture, Heterogeneity, And Origin Of Late Miocene Fluvial Deposits Hosting The Most Important Aquifer In The Great Plains, Usa, R. Matthew Joeckel, Steve R. Wooden Jr., Jesse T. Korus, Jon Garbisch

Department of Earth and Atmospheric Sciences: Faculty Publications

The Ash Hollow Formation (AHF) of the Ogallala Group is an important sedimentary archive of the emergence of the Great Plains and it contains major groundwater resources. Stratal patterns of constituent alluvial lithofacies demonstrate that the AHF is much more heterogeneous than is commonly assumed. Very fine- to fine-grained sandstone dominate overall, chiefly lithofacies Sm (massive to locally stratified sandstone). Stacked, thin sheets of Sm with accretionary macroform surfaces are common, indicating that many sandstone architectural elements originated as compound-bar deposits in dominantly sand-bed streams. Channel forms are difficult to identify and steep cutbanks are absent. Multiple units of lithofacies …

Tidal Pacing, Skipped Slips And The Slowdown Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Douglas A. Wiens, Martin J. Pratt

All Faculty Scholarship for the College of the Sciences

We summarize new observations of the deceleration and stick–slip motion of Whillans Ice Stream (WIS), Antarctica. We refine the location of the large sticky spots that resist motion between slip events, the locations of which are controlled by the patterns of subglacial water flow. Our examination of the long-term velocity time series for the ice stream reveals that the decadal-scale deceleration is not occurring at a steady rate, but varies at the sub-decadal timescale. This unsteady deceleration modulates the temporal evolution of a broad (~50 km across) surface-elevation bulge forming at the junction between the relatively narrow upstream portion of …

Thermobarometry And Geochronology In The Dulan Region, North Qaidam Ultrahigh-Pressure Terrane: Resolving Spatial Variation Of Ages, Temperatures, And Pressures, Megan Eileen Regel

All Master's Theses

The Dulan ultrahigh-pressure (UHP) terrane exposes 449-422 Ma eclogites in the east and 449-418 Ma high-pressure granulites to the west, but the relationship between the units is poorly understood. Zirconium-in-rutile temperatures show an east-west 3- 5°C/km gradient in four UHP eclogites: 662-716±10°C; garnet-omphacite-phengite thermobarometry of peak conditions yields 659-730±82°C, 25.3-27.1±3.2 kbars. Zircon U-Pb ages of four eclogites are the same within uncertainty, averaging 434±2.9 Ma. Tiin- zircon thermometry and rare earth element patterns indicate these ages represent eclogite facies metamorphism. One high-pressure/high-temperature (HP/HT) granulite yields a minimum rutile temperature of 773±4°C. Previous thermobarometry of highpressure granulites yields ≥800°C and 14-17 …

Ashfall Tephra In The Ogallala Group Of The Great Plains: Characteristics And Significance, Michael E. Perkins, Robert F. Diffendal Jr., Michael R. Voorhies, Barbara P. Nash, Bruce E. Bailey

Robert F. Diffendal, Jr., Publications

The Miocene Ogallala Group blankets the Great Plains east of the Rocky Mountains. This sheet of largely fluvial deposits, lying downwind of major silicic volcanic fields to the west, was ideally located to receive and preserve tephra from these fields. This investigation brings modern methods of tephrochronlogy to bear on the age and identity of Ogallala tephra. Results indicate that ~40 separate tephra layers, ranging in age from ~16.5–5.0 Ma, in the Ogallala. Most tephra came from Yellowstone hotspot sources. The relative frequency of hotspot tephra in the Ogallala matches that in more proximal regions to the west with peak …

Coupled Sediment Yield And Sediment Transport Model To Support Navigation Planning In Northeast Brazil, Calvin Trebor Creech

Wayne State University Dissertations

Deposition of sediment (shoaling) in commercial waterways is a major obstacle to maintaining sustainable riverine transportation of bulk goods (primarily agricultural and mining commodities). The rate of aggradation of sediment in a waterway is directly related to both the rate of sediment erosion from upland and river bank sources (sediment yield) and the energy in the river to effectively transport the sediment through the waterway system (sediment transport). Historically, methods used for waterway development have included trial and error or rules of thumb associated with river training structures and chute cut-off canals or engineering of navigation locks and dams. More …

Analysis Of Vesicular Porosity In Soils Using High-Resolution X-Ray Computed Tomograpy, Judith K. Turk, Robert C. Graham

Conservation and Survey Division: Faculty and Staff Publications

Vesicular horizons are common at the surface of arid and semiarid soils and play a critical role in regulating infiltration. Most methods for examining pore morphology in the vesicular horizon involve physical sectioning of the sample and individual measurement of pores, which is time-consuming and provides an incomplete view of the pores. The objectives of this study were to (i) develop methods for the classification and characterization of pores in the vesicular horizon using high resolution X-ray computed tomography (HRXCT) and (ii) use these methods to examine the distribution of pores within vesic-ular peds. Three intact peds were scanned by …

The Groundwater Atlas Of Lancaster County, Dana Divine

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Upper Pleistocene And Holocene Palaeoenvironmental Records In Cueva Mayor Karst (Atapuerca, Spain) From Different Proxies: Speleothem Crystal Fabrics, Palynology And Archaeology., Virginia Martínez-Pillado, Arantza Aranburu, Juan Luis Arsuaga, Blanca Ruiz-Zapata, Maria José Gil-García, Heather Stoll, Iñaki Yusta, Eneko Iriarte, José Miguel Carretero, R. Lawrence Edwards, Hai Cheng

International Journal of Speleology

The Cueva Mayor karst system of Atapuerca, in Northern Spain, hosts a highly significant record of human occupation from the Pleistocene. The climatic context of the human activities during the Pleistocene-Holocene for this inland site has not been well constrained, since existing records of the palaeoclimatic evolution of the Northern Iberian Peninsula are from more distal coastal and high-elevation sites. In this study, we interpret the palaeoenvironmental information recorded on the petrography of a stalagmite and the pollen spectra of the Sierra de Atapuerca karst system during the last 20 kyr. The integration of both types of records has allowed …

Long-Term Deformation In The Southern Rí­O Grande Rift As Inferred From Topographic And Uplifted Terraces, Linda K. Armour

Open Access Theses & Dissertations

This study examines Basin and Range topography relating tectonic processes to topographic features. The observation that the terraces along either side of the Franklin Mountains were deformed and uplifted is a reflection of tectonic uplift. The uplift represents long-term deformation of the range. This led to the question of what shapes the deformation and does it represent differential subsidence into the Río Grande Rift or true uplift. A more regional study of the Sacramento, San Andres, and Guadalupe Mountains follows. Two papers form this Dissertation.

The Rí­o Grande Rift and the Franklin Mountains, in particular, are the subject of the …

Wave Transformation At A Saltmarsh Edge And Resulting Marsh Edge Erosion: Observations And Modeling, Kevin J. Trosclair

LSU New Orleans Theses and Dissertations

This study examines wind generated waves during winter storms, their transformation/attenuation near the marsh edge, and the resulting saltmarsh edge erosion. A simple numerical model for wave generation, transmission and marsh edge erosion was developed and validated against observations from Lake Borgne, Louisiana. Results suggest that meteorological conditions modify the local water depth via wind or wave setup and atmospheric pressure, thus exerting a first order control on the location of wave attack, which in turn determines the type of wave forces (shear vs. impact) that dominate the erosion process. Scarp failure follows, at a location determined by water level, …

Surficial Geologic Map Of Kings Canyon: Implications For Relatively Slow Stream Incision Rates, Andrew Farris

Natural Resources Management and Environmental Sciences

Most of the Kings River in the Sierra Nevada Mountains of California has responded to regional uplift with rapid incision, creating the deepest canyon in the United States. However, Kings Canyon near Cedar Grove is still a mountainous relict landscape with little evidence of fluvial incision. Mapping took place in the Cedar Grove area of Kings Canyon to assess factors and/or processes causing relatively low stream incision rates in the region during Holocene time. A surficial geologic map was created in the field, along with visual observations of the South Fork of the Kings River and characterization of geologic map …

Sources Of Co2 Controlling The Carbonate Chemistry Of The Logsdon River, Mammoth Cave, Kentucky, Bruce Elliott Hatcher

Masters Theses & Specialist Projects

Logsdon River is a major, base-level stream within the Turnhole Bend Drainage basin of the Mammoth Cave System. The Logsdon River system has provided a unique opportunity to examine the geochemical evolution of a stream flowing through a major karst conduit that can be traversed for 10 km. This study examines CO₂ inputs at the upstream portion of the river, which provide major control for the river’s hydrochemistry. Samples were collected from the upstream portion of Logsdon River at what is referred to as the S-188 sump and also nearby at Crowbar Dome over the course of 44 weeks …

Glacier Slip And Seismicity Induced By Surface Melt, Peter L. Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Miriam Jackson, Mark E. Mathison, Denis Cohen

All Faculty Scholarship for the College of the Sciences

Many of the key processes governing fast glacier flow involve interaction between a glacier and its basal hydrological system, which is hidden from direct observation. Passive seismic monitoring has shown promise as a tool for remotely monitoring basal processes, but lack of glacier-bed access prevents clear understanding of the relationships between subglacial processes and corresponding seismic emissions. Here we describe direct measurements of basal hydrology, sliding, and broadband seismicity made in a unique subglacial facility in Norway during the onset of two summer melt seasons. In the most pronounced of these episodes, rapid delivery of surface meltwater to the bed …

Paleohydrology And The Origin Of Jewel Cave, Mike Wiles

National Cave and Karst Management Symposium 2013

With more than 267 m (166 miles) of mapped cave passages, Jewel Cave is the third longest cave in the world. The passages are beneath an area of 775 ha (3 mi²), located almost entirely within the Hell Canyon drainage basin. The canyon itself is situated in the bottom of a south-plunging syncline and most of the cave passages are located within the east limb. A down-dip cross section shows the cave passages assuming the shape of an elongate lens, located just below the Pahasapa/Minnelusa contact. The lower boundary is a maximum of 75 m (250 feet) below …