Earth Sciences Commons^™

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 Impact Of Decadal Land Cover Change On The Global Warming Potential Of Beringian Arctic Tundra, David Hwei-Len Lin

Open Access Theses & Dissertations

Arctic terrestrial ecosystems play an important role in the global carbon cycle. If arctic warming continues to rise as projected, large amounts of soil carbon stored in these ecosystems could be released to the atmosphere as carbon dioxide or methane and positively enhance greenhouse warming. Thus, improving understanding of the likely future state and fate of arctic soil carbon, and the carbon uptake potential of arctic terrestrial ecosystems are well recognized research priorities.

At the pan-arctic scale, decadal increases in NDVI (Normalized Difference Vegetation Index), an index of vegetation productivity, have been observed from satellite imagery, indicating a general greening …

Characterization Of Thrust Faults On The Moon Using Fault Dynamics And 3d Visualizations, Jaclyn Danielle Clark

Open Access Theses & Dissertations

Many small, lobate scarps, interpreted to be the surface traces of thrust faults, have been found all over Earth's moon by previous researchers. Fault dynamical calculations, assuming an initially completely molten Moon, have shown that these scarps can form due to compressional stresses that accumulate over time as the result of large-scale contraction of the Moon as it cooled. With high-resolution images from the Lunar Reconnaissance Orbiter Camera (LROC), previously undetected lobate scarps can be found globally and viewed at high resolution. By investigating these fault scarps, we can determine better constraints on the amount of crustal shortening and improve …

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 …

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 …

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. …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 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 …

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 …

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); …

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 …

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 …

Controlling Features And Processes For Radionuclide Release From Unsaturated Zone Geological Repositories, Lubna K. Hamdan

Open Access Theses & Dissertations

In the long run, nuclear waste packages will fail gradually due to localized and general corrosion and radionuclides will be transported to the accessible environment by ground water.

Two main failure scenarios are expected for the waste packages: Flow-through model and bathtub model; in the flow-through model water flows through the waste container, while in the bathtub model water pools inside the waste package. The Department of Energy, in their performance assessment of the proposed repository at Yucca Mountain, excluded the bathtub model from their analysis and assumed the diffusion and advection to be in the same direction in the …

Urban Development Under Extreme Hydrologic And Weather Conditions For El Paso-Juárez: Recommendations Resulting From Hydrologic Modeling, Gis, And Remote Sensing Analyses, Alberto Barud-Zubillaga

Open Access Theses & Dissertations

During the 2006 El Paso-Juárez flood there were many concerns regarding the capability of the existing stormwater system to handle 50- and 100-year flood events in El Paso, Texas and Juárez, Mexico area. Moreover in 2008, a considerable wet year from the normal 223 mm of annual precipitation for El Paso demonstrated that the area could very well received large amounts of precipitation at localized areas in short periods of time, representing a great flood threat to residents living in areas prone to flood. Some climate change projections for the area are exactly what had occurred over the last two …

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 - …

Mineralization In The San Juan Mountains, Colorado, William M. Sheriff

Open Access Theses & Dissertations

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Results Of New Petrologic And Remote Sensing Studies In The Big Bend Region, Stevan Christian Benker

Open Access Theses & Dissertations

The initial section of this manuscript involves the South Rim Formation, a series of 32.2-32 Ma comenditic quartz trachytic-rhyolitic volcanics and associated intrusives, erupted and was emplaced in Big Bend National Park, Texas. Magmatic parameters have only been interpreted for one of the two diverse petrogenetic suites comprising this formation. Here, new mineralogic data for the South Rim Formation rocks are presented. Magmatic parameters interpreted from these data assist in deciphering lithospheric characteristics during the mid-Tertiary.

Results indicate low temperatures (< 750 °C), reduced conditions (generally below the FMQ buffer), and low pressures (≤ 100 MPa) associated with South Rim Formation magmatism with slight conditional differences between the two suites. Newly discovered fayalite microphenocrysts allowed determination of oxygen fugacity values (between -0.14 and -0.25 ΔFMQ over temperature ranges of 680-700 °C), via mineral equilibria based QUILF95 calculations, for Emory Peak Suite.

Petrologic information is correlated with structural evidence from Trans-Pecos Texas and adjacent regions to evaluate debated timing of tectonic …

Application Of Copper And Zinc Isotopes To Fingerprint Metal Sources And Identify Attenuation Mechanisms In The Abandoned Waldorf Mine Area, Clear Creek County, Colorado, Suzan Aranda Luna

Open Access Theses & Dissertations

Acid rock drainage (ARD) is caused by the oxidative weathering of sulfide minerals. Sulfur is oxidized by dissolved oxygen or Fe(III) and sulfate ions, metals, and protons are released into the environment. Hence, the pH of nearby water and soils often decreases in response to ARD while metal concentrations increase. Because a large part of the Rocky Mountains of Colorado are highly mineralized (i.e., the Colorado Mineral Belt), ARD is a serious problem in this region. Moreover, the many abandoned mining areas in the Rocky Mountains that include waste rock piles, tailings impoundments, and surface disturbances add to the problem …

Characterization Of Mantle/Crust Interactions Using Pb Isotope Analyses Of Lavas In The Southern Rio Grande Rift, New Mexico, Lynnette Crocker

Open Access Theses & Dissertations

The Pb isotope composition of volcanic rocks in the Rio Grande Rift (RGR) can be used to investigate the interaction of mantle melts with continental lithosphere, and has important implications for the composition of the lithosphere. We suggest some compositional signatures may pre-date current tectonic processes. Existing data from several volcanic fields in New Mexico show a converging pattern on a very limited Pb isotope range, corresponding to lower crustal xenolith compositions from Kilbourne Hole. The different volcanic fields show Pb isotope trends diverging from this lower crustal composition, likely depicting mixing with different upper crustal reservoirs. These very common, …

Bagc.M: Three Dimensional Gravity Modeling Software With An Application In Death Valley, Ca, Brian Eugene Eslick

Open Access Theses & Dissertations

Basin Anomaly Gravity Calculator (BAGC.m) is a 3D interactive gravity modeling package designed to create, edit, and calculate the gravitational attraction of basin models entirely within the MATLABTM environment. Gravity anomalies are calculated using the Rectangular Prism Method (Bott, 1960; Kane, 1962; and Plouff, 1966) which subdivides earth models into regularly spaced rectangular prisms. This approach requires large 3D matrices to store most realistic earth models. The process of model editing is simplified by storing basins as 2D gridded files which define the depth to the boundary between basement rock and sedimentary fill for each model cell. In order to …