Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Geology (173)
- Environmental Sciences (147)
- Life Sciences (73)
- Hydrology (72)
- Oceanography and Atmospheric Sciences and Meteorology (67)
-
- Soil Science (60)
- Environmental Monitoring (45)
- Other Earth Sciences (41)
- Water Resource Management (40)
- Geochemistry (38)
- Geophysics and Seismology (38)
- Other Environmental Sciences (30)
- Social and Behavioral Sciences (29)
- Natural Resources Management and Policy (28)
- Environmental Indicators and Impact Assessment (27)
- Plant Sciences (26)
- Fresh Water Studies (23)
- Biogeochemistry (20)
- Geography (19)
- Climate (18)
- Natural Resources and Conservation (18)
- Engineering (17)
- Geomorphology (17)
- Oceanography (16)
- Agriculture (14)
- Glaciology (14)
- Ecology and Evolutionary Biology (13)
- Biology (12)
- Institution
-
- University of Nebraska - Lincoln (101)
- University of South Florida (40)
- TÜBİTAK (37)
- University of Kentucky (33)
- University of Nevada, Las Vegas (29)
-
- Louisiana State University (21)
- Boise State University (20)
- Missouri University of Science and Technology (16)
- California Polytechnic State University, San Luis Obispo (15)
- Department of Primary Industries and Regional Development, Western Australia (15)
- Old Dominion University (15)
- University of Texas at El Paso (15)
- Utah State University (13)
- Western Kentucky University (13)
- Brigham Young University (9)
- Central Washington University (9)
- Clemson University (9)
- Montclair State University (9)
- Portland State University (9)
- Smith College (9)
- Wright State University (9)
- University of South Carolina (8)
- Furman University (6)
- University of Texas at Arlington (6)
- West Chester University (6)
- Bryn Mawr College (5)
- Eastern Kentucky University (5)
- University of North Dakota (5)
- Columbus State University (4)
- Michigan Technological University (4)
- Keyword
-
- Water quality (13)
- Groundwater (12)
- Kentucky (12)
- Geochemistry (10)
- Department of Earth and Environmental Sciences (9)
-
- Karst (9)
- Research (9)
- Sediment (8)
- CGISS (7)
- Environmental studies (7)
- Geomorphology (7)
- Nebraska (7)
- Soil (7)
- Climate (6)
- Climate change (6)
- Copper (6)
- Environmental sciences (6)
- Furman University (6)
- Geology (6)
- Lake restoration (6)
- Salinity (6)
- Soil moisture (6)
- Agriculture (5)
- Antarctica (5)
- Caves (5)
- Drought (5)
- Geochronology (5)
- Geophysics (5)
- Hydrogeology (5)
- Natural resources (5)
- Publication
-
- Turkish Journal of Earth Sciences (37)
- Department of Earth and Atmospheric Sciences: Faculty Publications (33)
- United States Geological Survey: Staff Publications (28)
- LSU Master's Theses (19)
- UNLV Theses, Dissertations, Professional Papers, and Capstones (17)
-
- Open Access Theses & Dissertations (15)
- Studia UBB Geologia (14)
- Theses and Dissertations (13)
- International Journal of Speleology (12)
- Kentucky Alfalfa and Stored Forage Conference (11)
- Earth and Soil Sciences (10)
- All Theses (9)
- Browse all Theses and Dissertations (9)
- Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research (9)
- Faculty Publications (9)
- Geosciences: Faculty Publications (9)
- School of Geosciences Faculty and Staff Publications (9)
- Boise State University Theses and Dissertations (8)
- Department of Environmental Studies: Undergraduate Student Theses (8)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (8)
- Geosciences Faculty Publications and Presentations (7)
- OES Faculty Publications (7)
- Resource management technical reports (7)
- University of Kentucky Master's Theses (7)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (6)
- Furman Lake Restoration Book Gallery (6)
- Masters Theses & Specialist Projects (6)
- Theses, Dissertations and Culminating Projects (6)
- EKU Faculty and Staff Scholarship (5)
- Earth & Environmental Sciences Theses - Archive (5)
- Publication Type
Articles 481 - 510 of 581
Full-Text Articles in Earth Sciences
Abandoned Mine Drainage In The Swatara Creek Basin, Southern Anthracite Coalfield, Pennsylvania, Usa: 1. Stream Water Quality Trends Coinciding With The Return Of Fish, Charles A. Cravotta Iii, Robin A. Brightbill, Michael J. Langland
Abandoned Mine Drainage In The Swatara Creek Basin, Southern Anthracite Coalfield, Pennsylvania, Usa: 1. Stream Water Quality Trends Coinciding With The Return Of Fish, Charles A. Cravotta Iii, Robin A. Brightbill, Michael J. Langland
United States Geological Survey: Staff Publications
Acidic mine drainage (AMD) from legacy anthracite mines has contaminated Swatara Creek in eastern Pennsylvania. Intermittently collected base-flow data for 1959–1986 indicate that fish were absent immediately downstream from the mined area where pH ranged from 3.5 to 7.2 and concentrations of sulfate, dissolved iron, and dissolved aluminum were as high as 250, 2.0, and 4.7 mg/L, respectively. However, in the 1990s, fish returned to upper Swatara Creek, coinciding with the implementation of AMD treatment (limestone drains, limestone diversion wells, limestone sand, constructed wetlands) in the watershed. During 1996–2006, as many as 25 species of fish were identified in the …
In-Situ Stress And Fracture Characterization For Planning Of An Egs Stimulation In The Desert Peak Geothermal Field, Nevada, Stephen H. Hickman, Nicholas C. Davatzes
In-Situ Stress And Fracture Characterization For Planning Of An Egs Stimulation In The Desert Peak Geothermal Field, Nevada, Stephen H. Hickman, Nicholas C. Davatzes
United States Geological Survey: Staff Publications
An integrated study of natural fracture geometry, fluid flow and stress was conducted in Desert Peak well 27-15 in preparation for development of an Enhanced Geothermal System (EGS) through hydraulic stimulation. This stimulation will be carried out at depths of ~3000 to 3500 ft in units comprised of silicified rhyolite tuffs and metamorphosed mudstones at ambient temperatures of ~180 to 195° C. Our previous analyses of borehole image logs from this well showed that the current minimum horizontal principal stress, Shmin, is oriented 114 ± 17º and that numerous fractures in the planned stimulation interval are optimally oriented for normal …
Hydrogeophysical Methods For Analyzing Aquifer Storage And Recovery Systems, Burke J. Minsley, Jonathan Ajo-Franklin, Amitabha Mukhopadhyay, Frank Dale Morgan
Hydrogeophysical Methods For Analyzing Aquifer Storage And Recovery Systems, Burke J. Minsley, Jonathan Ajo-Franklin, Amitabha Mukhopadhyay, Frank Dale Morgan
United States Geological Survey: Staff Publications
Hydrogeophysical methods are presented that support the siting and monitoring of aquifer storage and recovery (ASR) systems. These methods are presented as numerical simulations in the context of a proposed ASR experiment in Kuwait, although the techniques are applicable to numerous ASR projects. Bulk geophysical properties are calculated directly from ASR flow and solute transport simulations using standard petrophysical relationships and are used to simulate the dynamic geophysical response to ASR. This strategy provides a quantitative framework for determining site-specific geophysical methods and data acquisition geometries that can provide the most useful information about the ASR implementation. An axisymmetric, coupled …
Subspecies Status And Population Genetic Structure In Piping Plover (Charadrius Melodus), Mark P. Miller, Susan M. Haig, Cheri L. Gratto-Trevor, Thomas D. Mullins
Subspecies Status And Population Genetic Structure In Piping Plover (Charadrius Melodus), Mark P. Miller, Susan M. Haig, Cheri L. Gratto-Trevor, Thomas D. Mullins
United States Geological Survey: Staff Publications
Piping Plover (Charadrius melodus) is a migratory shorebird that is listed as endangered in Canada and the U.S. Great Lakes and as threatened throughout the rest of its breeding and winter range. We undertook a comprehensive molecular-genetic investigation to (1) address subspecific taxonomy, (2) characterize population genetic structure, and (3) infer past bottlenecks and demographic processes in this species. Analyses included individuals from 23 U.S. states and Canadian provinces and were based on mitochondrial DNA sequences (580 base pairs, n = 245) and 8 nuclear microsatellite loci (n = 229). Our findings provide support for separate Atlantic and …
The Cleaning Of Burned And Contaminated Archaeological Maize Prior To 87sr/86sr Analysis, L.V. Benson, H. E. Taylor, T. I. Plowman, D. A. Roth, R. C. Antweiler
The Cleaning Of Burned And Contaminated Archaeological Maize Prior To 87sr/86sr Analysis, L.V. Benson, H. E. Taylor, T. I. Plowman, D. A. Roth, R. C. Antweiler
United States Geological Survey: Staff Publications
Accurate trace-metal and strontium-isotope analyses of archaeological corn cobs require that metal contaminants be removed prior to chemical analysis. Archaeological cobs are often coated with construction debris, dust, or soilwhich contains mineral particles. In addition, most archaeological cobs are partially or completely burned and the burned parts incorporate mineral debris in their hardened residual structures. Unburned cobs are weak ion exchangers and most metals within a cob are not firmly bound to cob organic matter; therefore, immersing cobs in acids and rinsing them in deionized water to remove mineral contaminants may result in the undesirable loss of metals, including strontium, …
Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta J. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato
Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta J. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato
United States Geological Survey: Staff Publications
The creation and use of a globally available database of DNA sequences from a standardized gene region has been proposed as a tool for species identification, assessing genetic diversity and monitoring the legal and illegal trade in wildlife species. Here, we contribute to the Barcode of Life Data System and test whether a short region of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene would reliably distinguish among a suite of commonly hunted African and South American mammal and reptile species. We used universal primers to generate reference barcode sequences of 645 bp for 23 species from five vertebrate …
The Role Of African Dust In The Formation Of Quaternary Soils On Mallorca, Spain And Implications For The Genesis Of Red Mediterranean Soils, Daniel R. Muhs, James Budahn, Anna Avila, Gary Skipp, Joshua Freeman, Deanna Patterson
The Role Of African Dust In The Formation Of Quaternary Soils On Mallorca, Spain And Implications For The Genesis Of Red Mediterranean Soils, Daniel R. Muhs, James Budahn, Anna Avila, Gary Skipp, Joshua Freeman, Deanna Patterson
United States Geological Survey: Staff Publications
African dust additions explain the origin of terra rossa soils that are common on the carbonate-platform island of Mallorca, Spain. Mineralogical and geochemical analyses indicate that Quaternary carbonate eolianites on Mallorca have a very high purity, usually composed of more than 90% carbonate minerals (calcite, dolomite, and aragonite). In contrast, terra rossa soils developed on these eolianites have lower carbonate contents and contain higher concentrations of quartz and other silicates. Analyses of immobile trace elements indicate that the non-carbonate fractions of the eolianites have distinctive Zr/Hf, La/Yb, Cr/Sc and Th/Ta values that differ from the superjacent terra rossa soils. These …
Assessing The Potential For Luminescence Dating Of Basalts, S. Tsukamoto, G. A.T. Duller, A. G. Wintle, Daniel R. Muhs
Assessing The Potential For Luminescence Dating Of Basalts, S. Tsukamoto, G. A.T. Duller, A. G. Wintle, Daniel R. Muhs
United States Geological Survey: Staff Publications
The possibility of dating basalt using luminescence was tested on four samples with independent age control from Cima volcanic !eld, California, with the ultimate aim of assessing whether the technique could be used to date sediments on the surface of Mars. Previous analysis of these samples had demonstrated that the infrared stimulated luminescence (IRSL) signal is most suitable for dating as it showed the lowest fading rate among various luminescence signals. In this study, changes in equivalent dose as a function of preheat are described. The ages for the two youngest Cima samples agree with the independent ages based on …
Carbon Dioxide Exchange In A Permafrost-Dominated Boreal Wetland In The Northwest Territories, Canada, Andrea J. Kenward
Carbon Dioxide Exchange In A Permafrost-Dominated Boreal Wetland In The Northwest Territories, Canada, Andrea J. Kenward
Theses and Dissertations (Comprehensive)
Northern boreal wetland complexes are substantial reservoirs for carbon and play a crucial role in both regional and global carbon budgets but they are showing significant signs of impact by climate change. This study examined the carbon dioxide flux of a high boreal wetland during the snowmelt and growing season of 2008 in Scotty Creek Basin, located near Fort Simpson (61°18'N, 121°18'W), Northwest Territories. This basin is not only responding to shifts in atmospheric temperatures, but it is also under additional pressure from increasing permafrost degradation. A dynamic closed-system chamber was used to monitor and quantify mid-day total respiration (R …
Ancient Dna Analyses Exclude Humans As The Driving Force Behind Late Pleistocene Musk Ox (Ovibos Moschatus) Population Dynamics, Paula F. Campos, Eske Willerslev, Andrei Sher, Ludovic Orlando, Erik Axelsson, Alexei Tikhonov, Kim Aaris-Sorensen, Alex D. Greenwood, Ralf-Dietrich Kahlke, Pavel Kosintsev
Ancient Dna Analyses Exclude Humans As The Driving Force Behind Late Pleistocene Musk Ox (Ovibos Moschatus) Population Dynamics, Paula F. Campos, Eske Willerslev, Andrei Sher, Ludovic Orlando, Erik Axelsson, Alexei Tikhonov, Kim Aaris-Sorensen, Alex D. Greenwood, Ralf-Dietrich Kahlke, Pavel Kosintsev
Biological Sciences Faculty Publications
The causes of the late Pleistocene megafaunal extinctions are poorly understood. Different lines of evidence point to climate change, the arrival of humans, or a combination of these events as the trigger. Although many species went extinct, others, such as caribou and bison, survived to the present. The musk ox has an intermediate story: relatively abundant during the Pleistocene, it is now restricted to Greenland and the Arctic Archipelago. In this study, we use ancient DNA sequences, temporally unbiased summary statistics, and Bayesian analytical techniques to infer musk ox population dynamics throughout the late Pleistocene and Holocene. Our results reveal …
Simulating Dioxane Transport In A Heterogeneous Glacial Aquifer System (Washtenaw County, Michigan) Using Publicly Available Models And Data, Rungroj Benjakul
Simulating Dioxane Transport In A Heterogeneous Glacial Aquifer System (Washtenaw County, Michigan) Using Publicly Available Models And Data, Rungroj Benjakul
Dissertations, Master's Theses and Master's Reports - Open
The primary challenge in groundwater and contaminant transport modeling is obtaining the data needed for constructing, calibrating and testing the models. Large amounts of data are necessary for describing the hydrostratigraphy in areas with complex geology. Increasingly states are making spatial data available that can be used for input to groundwater flow models. The appropriateness of this data for large-scale flow systems has not been tested. This study focuses on modeling a plume of 1,4-dioxane in a heterogeneous aquifer system in Scio Township, Washtenaw County, Michigan. The analysis consisted of: (1) characterization of hydrogeology of the area and construction of …
Differential Gps As A Monitoring Tool On Volcano Santa Ana (Illamatepec) And The Coatepeque Caldera, El Salvador, Hans N. Lechner
Differential Gps As A Monitoring Tool On Volcano Santa Ana (Illamatepec) And The Coatepeque Caldera, El Salvador, Hans N. Lechner
Dissertations, Master's Theses and Master's Reports - Open
We used differential GPS measurements from a 13 station GPS network spanning the Santa Ana Volcano and Coatepeque Caldera to characterize the inter-eruptive activity and tectonic movements near these two active and potentially hazardous features. Caldera-forming events occurred from 70-40 ka and at Santa Ana/Izalco volcanoes eruptive activity occurred as recently as 2005. Twelve differential stations were surveyed for 1 to 2 hours on a monthly basis from February through September 2009 and tied to a centrally located continuous GPS station, which serves as the reference site for this volcanic network. Repeatabilities of the averages from 20-minute sessions taken over …
La Yeguada Volcanic Complex, Western Panama : An Assessment Of The Geologic Hazards Using New 40Ar/39Ar Ages, Karinne L. Knutsen
La Yeguada Volcanic Complex, Western Panama : An Assessment Of The Geologic Hazards Using New 40Ar/39Ar Ages, Karinne L. Knutsen
Dissertations, Master's Theses and Master's Reports - Open
La Yeguada volcanic complex is one of three Quaternary volcanic centers in Panama, and is located on the southern slope of the Cordillera Central mountain range in western Panama, province of Veraguas. To assess potential geologic hazards, this study focused on the main dome complex near the village of La Laguna and also examined a cinder cone 10 km to the northwest next to the village of Media Luna. Based on newly obtained 40Ar/39Ar ages, the most recent eruption occurred approximately 32 000 years ago at the Media Luna cinder cone, while the youngest dated eruption at …
Measurements And Predictions Of Subsidence Induced By Soil Consolidation Using Persistent Scatterer Insar And A Hyperbolic Model, Sang-Wan Kim, Shimon Wdowinski, Timothy H. Dixon, Falk Amelung, Jeong W. Kim, Joong-Sun Won
Measurements And Predictions Of Subsidence Induced By Soil Consolidation Using Persistent Scatterer Insar And A Hyperbolic Model, Sang-Wan Kim, Shimon Wdowinski, Timothy H. Dixon, Falk Amelung, Jeong W. Kim, Joong-Sun Won
School of Geosciences Faculty and Staff Publications
A space-borne SAR interferometric technique is presented for measuring and predicting ground subsidence associated with soil consolidation. Instead of a conventional constant velocity model, a hyperbolic model is introduced for persistent scatterer SAR interferometry (PSI) processing. Twenty three JERS-1 SAR acquired between 1992 and 1998 were used to measure land subsidence in Mokpo city, Korea which had been primarily built on land reclaimed from the sea. Two subsidence field maps were derived and compared: a constant velocity model and a hyperbolic model. Non-linear components depending on the stage of soil consolidation are well represented by the hyperbolic model. The maximum …
Controlling Features And Processes For Radionuclide Release From Unsaturated Zone Geological Repositories, Lubna K. Hamdan
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
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
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
Mineralization In The San Juan Mountains, Colorado, William M. Sheriff
Open Access Theses & Dissertations
none
Results Of New Petrologic And Remote Sensing Studies In The Big Bend Region, Stevan Christian Benker
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
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
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
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 …
Studies Of Earthquakes Stress Drops, Seismic Scattering, And Dynamic Triggering In North America, Christian Rene Escudero Ayala
Studies Of Earthquakes Stress Drops, Seismic Scattering, And Dynamic Triggering In North America, Christian Rene Escudero Ayala
Open Access Theses & Dissertations
I use the Relative Source Time Function (RSTF) method to determine the source properties of earthquakes within southeastern Alaska-northwestern Canada in a first part of the project, and earthquakes within the Denali fault in a second part. I deconvolve a small event P-arrival signal from a larger event by the following method: select arrivals with a tapered cosine window, fast fourier transform to obtain the spectrum, apply water level deconvolution technique, and bandpass filter before inverse transforming the result to obtain the RSTF. I compare the source processes of earthquakes within the area to determine stress drop differences to determine …
Investigations Of Grade Control, Macarthur Mine, Yerington, Nevada: An Oxidized Porphyry Copper System, Joseph Daniel Louis Lori
Investigations Of Grade Control, Macarthur Mine, Yerington, Nevada: An Oxidized Porphyry Copper System, Joseph Daniel Louis Lori
Open Access Theses & Dissertations
Supergene enriched, low-grade oxidized porphyry copper deposits are of great economic value. Oxidized porphyry sections are economic targets because even low-grade prospects have the potential to produce low-cost copper in an environmentally friendly fashion due to easy leachability and high recovery rates of the oxide mineralization. The MacArthur Mine, in the historic Yerington mining district of Nevada, is the focus of this study. The MacArthur is a tilted oxidized porphyry deposit, partially mined by open pit methods, hosted in the Jurassic Bear Quartz Monzonite of the Yerington batholith. The objective of the study is to define controls of copper oxide …
Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete
Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete
Open Access Theses & Dissertations
Copper isotopes may prove to be a useful tool for investigating bacteria-metal interactions recorded in natural waters, soils, and rocks. However, experimental data that constrain Cu isotope fractionation in biologic systems are limited and unclear. In this study we utilized Cu isotopes (65Cu) as a tool to investigate Cu-bacteria interactions, including surface adsorption and intracellular incorporation. Experiments were conducted with individual Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacterial species as well as with bacterial consortia from several natural environments. Adsorption experiments were conducted with live or dead cells over the pH range 2.5 to 6. Surface adsorption of Cu …
Granulometry And Geochemistry Of Dust Emission From Owens (Dry) Lake, California, Analila Rojo
Granulometry And Geochemistry Of Dust Emission From Owens (Dry) Lake, California, Analila Rojo
Open Access Theses & Dissertations
Owens (dry) Lake, the terminus of Owens River, is located in the Basin and Range physiographic province in east–central California. The transformation of Owens Lake into a desiccated desert playa (approximately 280 km2) via diversion of the river into the Los Angeles Aqueduct (in 1913) led to extensive wind erosion, making the playa one of the most intense sources of airborne dust in the Western Hemisphere. The processes that direct the chemical and mineralogical composition of surface sediments at Owens (dry) Lake and the physical mechanisms of wind erosion, saltation and dust emission at Owens (dry) Lake are well–understood. However, …
Seismic Investigation Of The Southern Rio Grande Rift, Lennox Emmanuel Thompson
Seismic Investigation Of The Southern Rio Grande Rift, Lennox Emmanuel Thompson
Open Access Theses & Dissertations
Competing models exist to explain what caused the Earth's crust to spread apart 29 million years ago to create a region known today as the Rio Grande Rift (RGR). The RGR extends from central Colorado through New Mexico to northern Mexico, near El Paso. The RGR has different geologic features that distinguish it from most other valleys (e.g., the RGR was not cut by a river nor does a river branch upstream). A growing body of evidence shows that geologic activity still occurs in the RGR, with a continuation of faulting, seismicity and widening at a small rate of about …
Preliminary Archaeological Investigations At The Sierra Diablo Cave Site: Paleoindian And Archaic Occupations In Hudspeth County, Texas, Jose Javier Vasquez
Preliminary Archaeological Investigations At The Sierra Diablo Cave Site: Paleoindian And Archaic Occupations In Hudspeth County, Texas, Jose Javier Vasquez
Open Access Theses & Dissertations
It is generally rare to find archaeological sites in the Southwest that retain the type of contextual integrity that the Sierra Diablo Cave exhibits. Often times, cave sites such as the one currently studied offer excellent preservation of cultural materials due to the general lack of moisture and isolation from wind and water erosion. The research aimed to determine when the site was occupied as well as the types of activities that were occurring during those occupations. It exhibits an extensive stratigraphic sequence that contains a well pronounced Late Archaic Period assemblage (Strata A and B) and a Late Pleistocene/Early …
Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo
Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo
Open Access Theses & Dissertations
Silica and nanoparticles of Pt, Au, and Ag supported on silica were tested for the ability to oxidize dibenzothiophene (DBT) to sulfone. High performance liquid chromatography was used to study the removal of DBT from solution. In addition, X- ray diffraction, infrared spectroscopy and Raman Spectroscopy were used to characterize the product of the oxidation reaction. Further studies involved the use X-ray absorption spectroscopy to characterize the nanoparticle catalysts before and after the oxidation reaction.
To better understand the reaction, silica was synthesized at different pHs using three different acids. The acids used to synthesize the silica were HCl, HNO3, …
Sonolytic Degradation Of Parathion And The Formation Of Byproducts, Juan Juan Yao, Nai Yun Gao, Yang Deng, Yan Ma, Hai Jun Li, Bin Xu, Lei Li
Sonolytic Degradation Of Parathion And The Formation Of Byproducts, Juan Juan Yao, Nai Yun Gao, Yang Deng, Yan Ma, Hai Jun Li, Bin Xu, Lei Li
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
Ultrasonic degradation of parathion has been investigated in this study. At a neutral condition, 99.7% of 2.9 μM parathion could be decomposed within 30 min under 600 kHz ultrasonic irradiation at ultrasonic intensity of 0.69 W/cm2. The degradation rate increased proportionally with the increasing ultrasonic intensity from 0.10 to 0.69 W/cm2. The parathion degradation was enhanced in the presence of dissolved oxygen due to formation of more {radical dot}OH, but was inhibited in the presence of nitrogen gas owning to the free radical scavenging effect in vapor phase within the cavitational bubbles. CO32 -, HCO3-, and Cl- exhibited the inhibiting …