Physical Sciences and Mathematics Commons^™

Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas

Open Access Theses & Dissertations

The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, an important petroleum province within south-central Alaska. A primary goal in the research is to test several plausible models of structure along the Border Ranges Fault System using a novel three-dimensional inversion utilizing gravity and magnetic data, constrained with other geophysical, borehole and surface geological information. This research involves the development of inversion modeling software using a Borland C++ compiler as part of the Rapid Application Development (RAD) Studio. The novel inversion approach directly models known geology, and "a priori" uncertainties on the geologic model to allow …

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 …

A Proposed Epithermal Model For The High Grade District, California, Michael Nicholas Feinstein

Open Access Theses & Dissertations

A historic gold mining district in northeastern California has not been incorporated into the global knowledge base for precious metal vein deposits. This study collected various data types which are important characteristics in the classification and understanding of vein deposits. The High Grade District (HGD) is a gold mining site located in the northeast corner of Modoc County, California, in the Warner Mountains. The Warner Mountains are composed of Tertiary eruptive centers, cropping out between valleys formed through extensional tectonics. Mineralization of the HGD displays abundant silicification, adularia, and gold; these characteristics are sufficient to classify mineralization as low-sulfidation epithermal …

An Integrated Geological And Geophysical Study Of The Fresh And Brackish Water Boundary In The Hueco Bolson, West Texas, Sandy Stephanie Marrufo

Open Access Theses & Dissertations

The Hueco Bolson in West Texas is located in the Rio Grande rift basin and provides water to El Paso County, Texas and Juarez, Mexico. El Paso Water Utilities (EPWU) drilled many wells up to 1000 ft (305) m into this aquifer, which provide 40% of El Paso's water supply. Stratigraphy and sedimentation in active extensional basins have received little study because they are usually buried and this research helped document these processes. The study area within the West Texas region of the Hueco Bolson Aquifer (HBA) lies within a transition zone between the fresh and brackish water sections of …

Patterns And Controls Of Erosion Along The Barrow Environmental Observatory Coastline, Northern Alaska, Adrian Aguirre

Open Access Theses & Dissertations

With pronounced arctic warming that is linked to loss of sea ice, sea level rise, and land cover change, over the coming decades arctic coastal regions are likely to undergo amongst the most dramatic changes of any ecosystem on Earth. This study used foot surveys and a Differential Global Positioning System (DGPS) to document at a high spatial (horizontal and vertical) resolution, the spatiotemporal dynamics of the eroding bluff along the coastline of the Barrow Environmental Observatory between 2003 and 2009. The coastline consists of an eroding bluff bordered by a shallow muddy lagoon. The coast is protected from strong …

Implications Of Surface Runoff Recharge In Semi-Arid Regions On Groundwater Sustainability, Omar M. Al-Qudah

Open Access Theses & Dissertations

Amargosa Desert, Nevada regional groundwater studies show that the surface runoff infiltration occurring in the arroyos following runoff producing storms, and this infiltration is considered to be a major source of groundwater recharge. Groundwater infiltration through alluvium was investigated in the Amargosa Desert using borehole drill cuttings, groundwater chemistry, and applying a novel method for collecting runoff water. The sampling process included sediment, precipitation, and runoff water. In total, 176 runoff, 182 sediment, and 45 precipitation samples were collected between January, 2009 and January, 2011.Water chemistry, chloride concentrations, and stable isotopes of water collected from specially designed runoff samplers, placed …

Nummulites Biofabrics As Tool For Quality Evaluation Of The Eocene Jdeir Formation Reservoirs Nw Offshore, Libya, Abdusalam Ali Agail

Open Access Theses & Dissertations

The southern Tethys margin constitutes an important hydrocarbon reservoir. It is formed mainly of Nummulite rich facies of the Jdeir Formation deposited during the Eocene epoch (Late Ypresian age) in the giant El-Bouri oil field-Sabratah Basin-NW Libya. Deposits of the Jdeir Formation directly overlay the Jirani dolomite and Bilal Formation, and unconformably underlay the Tellil Group and Ghallil Formation.

Nummulite accumulations are good indicators for hydrocarbon studies and they have been targets for numerous studies around the world. Nummulite "Large foraminifera" tests are usually identified by two forms: A-form and B-form. Previous studies have highlighted many different aspects of foraminifers …

Gpu Based Parallel Smoothing Of Seismic Tomography Models, Ivan Gris

Open Access Theses & Dissertations

Three-dimensional models of the velocity structure of the Earth's crust are an important and relevant factor for several types of analyses across disciplines. Crustal velocity models are also commonly used to analyze and search for different materials of interest or to determine and differentiate many aspects of life on Earth during different eras.

Seismic tomography techniques, both in two and three dimensions, perform image reconstruction of the crust of the Earth. Seismic tomography algorithms can calculate crustal velocity structure through inversion of traveltimes of seismic waves produced by natural events, such as earthquakes, or controlled source experiments, such as explosions. …

The Impact Of Sulfide Mineral Weathering On The Isotopic Signatures Of Fe And Cu In Metal-Rich Streams, Ana Lourdes Gutierrez

Open Access Theses & Dissertations

The oxidative weathering of sulfide minerals, like pyrite, at the Earth's surface controls the formation of acid mine drainage sites as well as the Fe isotope composition of these areas and the main processes taken place. In this study, water and rock samples were collected from acidic drainages (most from abandoned mining sites) from the St. Juan Mountains in Colorado. The water samples were measured in-situ for dissolved oxygen, dissolved Fe(II), pH, and conductivity. Filtered acidified, unfiltered acidified, and Fe-oxide samples were analyzed for their metal concentrations. Ion-exchange chromatography was applied to both water and digested oxide fractions in order …

An Integrated Geographic Information Systems (Igis) Analysis And Definition Of The Tectonic Framework Of Northern Mexico, Carlos Manuel Martinez

Open Access Theses & Dissertations

Crustal rupture structures reactivated in the course of the tectonic history of northern Mexico are the surface expressions of planes of weakness, in the form of simple or composite rectilinear features or slightly curved, defined as lineaments. Unless otherwise defined as strike-slip faults, lineaments are part of parallel and sub-parallel oblique convergent or oblique divergent tectonic zones cross cutting the Sierra Madre Occidental and northern Mexico, in a NW trend. These shear zones are the response to the oblique subduction of the Farallon plate beneath North America.

Kinematic analysis of five selected sites in northern Mexico, three basins and two …

Fold-Thrust System Overprinting Syn-Rift Structures On The Margin Of An Inverted Rift Basin: Indio Mountains, West Texas, Seth Joel Page

Open Access Theses & Dissertations

Detailed mapping in the central Indio Mountains in west Texas, reveal a complex stacking of thrust sheets that record inversion of the Mesozoic Chihuahua Trough rift basin. Important newly recognized structural complexities include both folding of older thrust sheets and development of younger, out-of-sequence thrusts that cut across older folds; detachment fold horizons within thrust sheets; and a regional anticlinorium that exposes the Squaw thrust in a structural half-window bounded on the west by the Neogene Indio normal fault. The Chihuahua trough originated as part of the late Mesozoic border rift system and was inverted during Laramide thrusting. Remnants of …

Evaluating Suspended Dust Particulate Matter From Anthropogenically - Altered Lands, Roberto Velarde

Open Access Theses & Dissertations

Substantial dust loads are transported from drylands including the Saharan, Asian, and Chihuahuan Desert deposits by localized to planetary-scale processes to nearby and distal sites. These dusts may carry harmful constituents. To evaluate dust movement patterns and characteristics relative to carried constituents, three studies are presented comprising (A) Localized displacement of uranium and progeny radionuclides from high-grade uranium ore storage piles at Peña Blanca, Chihuahua, Mexico; (B) Long-distance transport of plutonium via Saharan and Asian aeolian pathways; and (C) Dust movement patterns in military maneuvering and non-maneuvering areas at White Sands Missile Range (WSMR), New Mexico. Study (A) evaluated surface …

Joint Geophysical Data Analysis For Geothermal Energy Exploration, Antony Munika Wamalwa

Open Access Theses & Dissertations

Geophysical data modelling often yields non-unique results and hence the interpretation of the resulting models in terms of underlying geological units and structures is not a straightforward problem. However, if multiple datasets are available for a region of study, an integrated interpretation of models for each of the geophysical data may results to a more realistic geological description. This study not only demonstrates the strength of resistivity analysis for geothermal fields but also the gains from interpreting resistivity data together with other geophysical data such as gravity and seismic data. Various geothermal fields have been examined in this study which …

An Investigation Of The Seismic Hazards Of The El Paso-Juarez Region: The Nature And Extent Of The Southern East Franklin Mountains Fault Zone, Victor Manuel Avila

Open Access Theses & Dissertations

ABSTRACT

The El Paso-Ciudad Juarez Region is situated at the southern end of the active Rio Grande Rift within the Mesilla and Hueco basins. The Hueco basin is separated from the eastern Franklin Mountains by a prominent fault, the Eastern Boundary Fault. Studies of this fault have revealed fault scarps that displace Quaternary deposits (Keaton et al., 1995; Raney and Collins, 1990; Lovejoy, 1976). This fault is cataloged as an active fault in the National Seismic Hazard Map with an estimated slip rate of 0.1 mm/yr. A fault with similar characteristics as the Eastern Boundary Fault extends further to the …

Seismological Studies In South-Central Alaska And Northern Mexico, Oscar Mario Romero De La Cruz

Open Access Theses & Dissertations

The work in this study is focused on two different areas, south-central Alaska and northern Mexico. In the first study area, I calculated dynamic stress drops for moderate sized earthquakes and performed receiver function analyses. The goal of the stress drop studies was to determine if events occurring within the more strongly coupled portion of the subducting slab have higher stress drops. My results shows that higher stress drops correspond to the locked and strongly coupled region in Prince William Sound, and lower stress drops are associated with the Cook Inlet region, a zone of relaxation of the plate interface. …

Structural And Tectonic Investigation Of A Transpressional System, Chugach Metamorphic Complex, Southern Alaska, Mitchell Ryan Scharman

Open Access Theses & Dissertations

Late Cretaceous to Eocene ridge subduction beneath the Mesozic Chugach terrane accretionary complex resulted in the formation of the Chugach metamorphic complex, and anomolus near trench plutonism of the Sanak-Baranof plutonic belt. The Chugach metamorphic complex (CMC), southern Alaska, is a high-temperature/low-pressure metamorphic belt, that offers a down plunge view of the mid- to lower-crust of a dextral transpression system. A distinct progression of deformation is recognized in the complex: 1) D1 contraction throughout the Chugach accretionary complex, 2) D2 margin parallel extension and horizontal simple shear, associated with subduction of higher ridge topography, followed by 3) D3 dextral transpression …

On Constrained Optimization Schemes For Joint Inversion Of Geophysical Datasets, Uram Anibal Sosa Aguirre

Open Access Theses & Dissertations

In the area of geological sciences, there exist several experimental techniques used to advance in the understanding of the Earth. We implement a joint inversion least-squares (LSQ) algorithm to characterize one dimensional Earth's structure by using seismic shear wave velocities as a model parameter. We use two geophysical datasets sensitive to shear velocities, namely Receiver Function and Surface Wave dispersion velocity observations, with a choice of an optimization method: Truncated Singular Value Decomposition (TSVD) or Primal-Dual Interior-Point (PDIP). The TSVD and the PDIP methods solve a regularized unconstrained and a constrained minimization problem, respectively. Both techniques include bounds into the …

Evidence Of Ancient Rifts Beneath Texas, Keisuke Irie

Open Access Theses & Dissertations

Continental rifts are defined as geological features where Earth's lithosphere is pulled away by surface expansion of the Earth. Their physiographic features include linear rift valleys associated with active volcanism. Many rifts fail to split a continent and ancient rifts that failed to split can be found by using seismic waves to image these ancient structures. Using seismic data collected by EarthScope USArray stations in Texas, teleseismic receiver functions was calculated and utilized surface wave dispersion curves to simultaneously invert for the 2D velocity structure beneath each seismic station. EarthScope is a scientific program funded by NSF that provides geophysical …

Dispersion Geochemistry At Different Scales At The Nopal I Deposit, Peña Blanca Uranium District, Chihuahua, Mexico, Katrina Pekar-Carpenter

Open Access Theses & Dissertations

The Nopal I mine in the Peña Blanca Uranium District, Chihuahua, Mexico is a natural analog for the geologic storage of nuclear waste. This dissertation presents data from two sites within Nopal I: 1) the PB-1 core, which was drilled along the extent of uranium mineralization in the Nopal I mine; and 2) a high-grade stockpile boulder from the mineralized Nopal tuff.

The PB-1 core allowed an investigation into the mineralogical and geochemical changes that are important to research on a nuclear waste repository. Five zones were determined to control these changes: 1) Zone 1, the primary uranium mineralization (quartz-uraninite-pyrite-kaolinite-ilmenite); …