Earth Sciences Commons^™

Grid Independence Studies Of Eddy-Resolving Models At The Scale Of A River Reach Along A Transect In Marble Canyon Of The Colorado River, Arizona, Rosa Elena España Urresty

Open Access Theses & Dissertations

This study presented a novel approach for evaluating the impact of changes in spatial resolution on field-scale models to identify turbulent flow patterns in hydraulic features in canyon-bound rivers. The methodological framework incorporated seven different computational domain resolutions to analyze the sensitivity of field-scale models to spatial resolution changes by employing techniques such as turbulent kinetic energy spectrum, spatiotemporal analysis of eddy structures, divergent Kullback-Leibler (KL) divergence, Nash-Sutcliffe (NS) model efficiency coefficient, wavelet power spectrum, and GCI calculation. Statistical and physical-based skill metrics are employed to quantifying information loss to evaluate a set of domain resolutions. Grid independence studies have …

Onshore-Offshore Velocity Models North Of The Mendocino Triple Junction In Northern California, Alan Jacquez

Open Access Theses & Dissertations

The Mendocino Triple Junction (MTJ) marks the boundary where the Gorda plate, North American Plate, and Pacific Plate meet, separating the Cascadia subduction zone to the North from transform tectonics of the San Andreas plate boundary. This actively deforming region experiences high seismic activity and young geological features. Here we examine offshore and onshore seismic wide-angle reflection and refraction data north of the MTJ crossing the Cascadia subduction zone from offshore northern California to the Western edge of the Sierra Nevada. We image subsurface structures in this region by creating P-wave velocity models using datasets collected in 1993 to 1994 …

A Quantitative Analysis Of The Fretted Terrain Valleys, Arabia Terra, Mars, Kelsey Anne Mason

Open Access Theses & Dissertations

Fretted terrain describes regions on Mars with low-lying, flat valleys separated by steep cliffs that often form polygonal-shaped mesas. The fretted terrain valleys have a morphology distinct from other valleys found on Mars, and their unknown origin may hold insights into critical questions about Mars' tectonic, magmatic, and hydrologic history. Current hypoThesis for the formation of the fretted terrain include fracturing as well as hydrological flow processes such as fluvial or glacial erosion. The region for this study is located in eastern Arabia Terra and is the type-location for fretted terrain. By qualitatively and quantitatively documenting the planform, or map-view, …

Reconstructing Late Pleistocene And Holocene Paleoenvironments Using Playa-Lunette System Sediments Within The Harney Basin Of Southeastern Oregon, Usa, Joe Collins

Open Access Theses & Dissertations

Paleoenvironmental investigations of the Late Pleistocene and Early Holocene in the Harney Basin of eastern Oregon have been limited to date. This Dissertation investigates and links the stratigraphy of Rimrock Draw Rockshelter (35HA3855) (RDR) and two surrounding playas, Rimrock Lake and Hay Lake, located on the western margin of the Harney Basin, in order to identify paleoenvironmental shifts during the last ~20 kyr. An emphasis also is given to demonstrating the potential for playas in the Harney Basin to record changes in paleoclimate, as well as the application of multivariate statistics to interpret paleoenvironments from sedimentary grain size data. Stratigraphy …

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 …

Application Of Various Remote Sensing And Aerial Photography Data Sets To Resolve Surface Structure In Areas Of Poor Exposure: Examples From Kamchatka Peninsula, Russia And Katalla Area, Alaska Usa, Sarah Natalie Heinlein

Open Access Theses & Dissertations

For many years now remote sensing data sets and application techniques of these various data have been routinely used in geological studies. Some of these studies are as basic as using Google Earth applications for general reconnaissance to more sophisticated methods for energy exploration or development of active tectonic models for a region. This dissertation presents data from two study areas within the northern pacific region utilizing a number of remote sensing and aerial photography data: 1) Kamchatka Peninsula, Russia, and 2) Katalla area of southern Alaska, USA. The Kamchatka Peninsula, Russia study evaluates surface geomorphology which includes the morphology …

Grain Size Distribution With Geomorphology On Gypsum Dunes In The White Sands Erg, White Sands National Monument, New Mexico, Slade Jones

Open Access Theses & Dissertations

In order to examine grain size distribution over dunes at the White Sands dune field, 1214 geolocated surficial samples were collected and analyzed by laser diffraction. Local variations in dunes such as neighboring interdune types and the presence of vegetation, deflation features, and granule ripples on the dunes were noted. This study indicates that recrystallization of gypsum and the generation of fresh sediments is occurring in significant quantities within interdunes, providing both high and low anomalies in grain size distribution through much of the central portion of the dune field. Other local variations as previously mentioned such as scour surfaces …

The East Jhomolari Fault System And The Timing Of East-West Extension In Northwest Bhutan, John Matthew Cannon

Open Access Theses & Dissertations

This investigation documents a little known, regionally significant, high angle, southeast dipping, system of normal faults in northwest Bhutan, the East Jhomolari Fault System (EJFS). The EJFS trends parallel to the Yadong Gulu rift (YG) and can be traced from Mt. Jhomolari to the northern border with Tibet. This fault zone has been demonstrably active since the last glacial maximum and there is geomorphic evidence of Holocene activity on some fault segments. The structurally lowest EJFS fault, the Lingshi fault appears on some published maps, but the full geographic extent, displacement, onset of faulting, and most recent activity have not …

Tectonic Geomorphology Of The Puna Tsang Chhu, Western Bhutan, Abby May Woody

Open Access Theses & Dissertations

There are two boundaries, or physiographic transitions, between three distinct topographic regions in Bhutan. The southern and northern regions have relatively steep hillslopes and high relief, while the central region has gentle hillslopes and low relief. The geomorphology of a 70-km stretch along the Puna Tsang Chhu valley between the towns of Uma and Amrimo was studied in March and April of 2009 to provide constraints on the active tectonics of western Bhutan and the nature of these physiographic transitions.

The Puna Tsang Chhu valley contains a set of alluvial cut-and-fill and bedrock (strath) river terraces with associated sediments - …