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2018

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Articles 1051 - 1080 of 1193

Full-Text Articles in Earth Sciences

Evaluating Restored Tidal Freshwater Wetlands, Andrew H. Baldwin, Richard S. Hammerschlag, Donald R. Cahoon Jan 2018

Evaluating Restored Tidal Freshwater Wetlands, Andrew H. Baldwin, Richard S. Hammerschlag, Donald R. Cahoon

United States Geological Survey: Staff Publications

Tidal freshwater wetlands are recognized as highly productive coastal wetlands that support diverse assemblages of plants and animals and complex biogeochemical cycles (in this book, see Chapter 18 by Whigham et al. and Chapter 19 by Megonigal and Neubauer). Many tidal freshwater wetlands and their associated ecosystem services have been damaged or destroyed by urbanization, agriculture, and other human activities (Baldwin, 2004; Barendregt et al., 2006). Increasing recognition of the value of remaining wetlands and environmental regulations requiring wetland mitigation (i.e., enhancement, creation, or restoration of wetlands to compensate for wetland losses; Kentula, 2000) has driven the restoration of all …


Evaluating The Waterfowl Breeding Population And Habitat Survey For Scaup, Michael L. Schummer, Alan D. Afton, Shannon S. Badzinski, Scott A. Petrie, Glenn H. Olsen, Mark A. Mitchell Jan 2018

Evaluating The Waterfowl Breeding Population And Habitat Survey For Scaup, Michael L. Schummer, Alan D. Afton, Shannon S. Badzinski, Scott A. Petrie, Glenn H. Olsen, Mark A. Mitchell

United States Geological Survey: Staff Publications

Potential bias in breeding population estimates of certain duck species from the Waterfowl Breeding Population and Habitat Survey (WBPHS) has been a concern for decades. The WBPHS does not differentiate between lesser (Aythya affinis) and greater (A. marila) scaup, but lesser scaup comprise 89% of the combined scaup population and their population estimates are suspected to be biased. We marked female lesser scaup (i.e., marked scaup) in the Mississippi and Atlantic Flyways, Canada and United States, with implantable satellite transmitters to track their spring migration through the traditional and eastern survey areas of the WBPHS, 2005–2010. Our goal was to …


Risks And Hazards Of Rodenticide To Non-Raptor Birds, Nimish B. Vyas Jan 2018

Risks And Hazards Of Rodenticide To Non-Raptor Birds, Nimish B. Vyas

United States Geological Survey: Staff Publications

Incident data can support risk assessments by providing evidence of adverse effects of rodenticides to birds following operational applications. Traditionally, field monitoring for rodenticide incidents has focused primarily on raptors. However, nonraptor birds may also be poisoned (rodenticide exposure resulting in adverse effects including mortality) by rodenticides through consumption of the rodenticide bait and contaminated prey. I conducted a literature search canvassing 12 government and scholarly databases for rodenticide incidents (evidence of exposure to a rodenticide, adverse effects, or exposure to placebo baits) involving non-raptor birds. I used the search terms ‘rodenticide’ and ‘birds’ and from these results, I excluded …


The Role Of Channel Fens In Permafrost Degradation Induced Changes In Peatland Discharge At Scotty Creek, Nt, Lindsay Elena Stone Jan 2018

The Role Of Channel Fens In Permafrost Degradation Induced Changes In Peatland Discharge At Scotty Creek, Nt, Lindsay Elena Stone

Theses and Dissertations (Comprehensive)

Permafrost degradation in the peat-rich southern fringe of the discontinuous permafrost zone is producing substantial changes to land cover with concomitant expansion of permafrost-free wetlands (bogs and fens) and shrinkage of forest supported by permafrost peat plateaus. Predicting discharge from headwater basins in this region depends on understanding and numerically representing the interactions between storage and discharge within and between the major land cover types, and how these interactions are changing. To better understand the implications of land cover change on wetland discharge, the hydrological behaviour of a channel fen in the headwaters of Scotty Creek, Northwest Territories, Canada, dominated …


Can Increasing Grass-Fungal Endophyte Symbiotic Diversity Enhance Grassland Ecosystem Functioning?, Mahtaab Bagherzadeh Jan 2018

Can Increasing Grass-Fungal Endophyte Symbiotic Diversity Enhance Grassland Ecosystem Functioning?, Mahtaab Bagherzadeh

Theses and Dissertations--Plant and Soil Sciences

The relationship between biodiversity and ecosystem functioning is important in maintaining agroecosystem sustainability. Plant-microbe symbioses, such as exists between the grass tall fescue (Schedonorus arundinaceum) and the asexual fungal endophyte Epichloë coenophiala, can be utilized to enhance agroecosystem functions, such as herbivore resistance. “Novel” E. coenophiala strains that vary in the production of mammal- and insect-toxic compounds have been identified, inserted into tall fescue cultivars, and are planted in pastures globally. Novel fungal endophyte-tall fescue associations may have divergent ecosystem function effects. This study assessed effects of different fescue-endophyte symbiotic combinations on pasture ecosystem function, including aboveground …


Exploring Spatial And Temporal Variability Of Soil And Crop Processes For Irrigation Management, Javier Reyes Jan 2018

Exploring Spatial And Temporal Variability Of Soil And Crop Processes For Irrigation Management, Javier Reyes

Theses and Dissertations--Plant and Soil Sciences

Irrigation needs to be applied to soils in relatively humid regions such as western Kentucky to supply water for crop uptake to optimize and stabilize yields. Characterization of soil and crop variability at the field scale is needed to apply site specific management and to optimize water application. The objective of this work is to propose a characterization and modeling of soil and crop processes to improve irrigation management. Through an analysis of spatial and temporal behavior of soil and crop variables the variability in the field was identified. Integrative analysis of soil, crop, proximal and remote sensing data was …


A Bayesian Hierarchical Approach To Multivariate Nonstationary Hydrologic Frequency Analysis, C. Bracken, K. D. Holman, B. Rajagopalan, Hamid Moradkhani Jan 2018

A Bayesian Hierarchical Approach To Multivariate Nonstationary Hydrologic Frequency Analysis, C. Bracken, K. D. Holman, B. Rajagopalan, Hamid Moradkhani

Civil and Environmental Engineering Faculty Publications and Presentations

We present a general Bayesian hierarchical framework for conducting nonstationary frequency analysis of multiple hydrologic variables. In this, annual maxima from each variable are assumed to follow a generalized extreme value (GEV) distribution in which the location parameter is allowed to vary in time. A Gaussian elliptical copula is used to model the joint distribution of all variables. We demonstrate the utility of this framework with a joint frequency analysis model of annual peak snow water equivalent (SWE), annual peak flow, and annual peak reservoir elevation at Taylor Park dam in Colorado, USA. Indices of largescale climate drivers—El Ni~no Southern …


Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon Jan 2018

Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon

Dissertations and Theses

This study investigates the influence of tropical deep convection on distribution of trace gasses in the tropical upper troposphere (UT) using data from the Convective Transport of Active Species in the Tropics (CONTRAST) Experiment conducted over the tropical western Pacific during January and February of 2014. Fifty-five chemical species measured during the CONTRAST campaign are analyzed with lifetimes ranging from less than a day to several years. The vertical profiles of these species suggest that they fall into three main groups delineated by their lifetime: 1) very long-lived trace gases demonstrating a nearly constant vertical structure, 2) intermediate lifetime species …


Tuhualite In A Peralkaline Rhyolitic Ignimbrite From Pantelleria, Italy, Boguslaw Baginski, Ray Macdonald, John C. White, Lidia Jezak Jan 2018

Tuhualite In A Peralkaline Rhyolitic Ignimbrite From Pantelleria, Italy, Boguslaw Baginski, Ray Macdonald, John C. White, Lidia Jezak

EKU Faculty and Staff Scholarship

An occurrence of the rare mineral tuhualite (NaFe3+Fe2+Si6O15) is reported in a peralkaline rhyolitic ignimbrite from the 11 island of Pantelleria, Italy. The mineral formed during devitrification of glassy fiamme and varies in form from anhedral plates to 12 perfect euhedral in open vesicles. There is significant replacement of Fe2+ by Mn (FMQ in the presence of a 14 hydrous fluid.


Geochemical Differences In Calcic Horizons Due To Parent Material And Anthropogenic Water Input In Southeastern Arizona, Alicia Fischer Jan 2018

Geochemical Differences In Calcic Horizons Due To Parent Material And Anthropogenic Water Input In Southeastern Arizona, Alicia Fischer

Honors Theses

Calcic soil horizons are significant carbon sinks. Yet, despite their abundance in semiarid environments, calcic soils are enigmatic for two reasons: (1) some authors hypothesize that dust input does not, independently, control the geochemical properties of these soils; and (2) few studies have examined how these calcic soils change geochemically with respect to irrigation. A 2017 pilot study used portable x-ray fluorescence (pXRF) on calcic soils in Southeastern Arizona (SEAZ) to address these questions. However, this technology has not been widely employed to evaluate soils. The current study addresses whether pXRF and XRF data obtained from the same soil samples …


Assessing The Use Of Tsunami Simulations As A Tool To Predict Source Magnitudes And Locations Of Paleoearthquakes In Chile, Rebeca Isabel Becerra Jan 2018

Assessing The Use Of Tsunami Simulations As A Tool To Predict Source Magnitudes And Locations Of Paleoearthquakes In Chile, Rebeca Isabel Becerra

All Master's Theses

A long-term goal of paleotsunami studies is the ability to predict paleoearthquake parameters based on tsunami deposits found on land. Chile provides an exemplary location for testing methods of making these predictions because the historical record includes 41 major earthquakes as far back as 1562 AD, and there are many known paleotsunami deposits throughout the region. Using these records as a comparison tool, I evaluated simulated tsunami wave heights and inundation extent with the tsunami model GeoClaw for nine hypothetical tsunamigenic large earthquakes (Mw 8.6, 8.8, and 9.0) in south-central Chile with epicenters at -35.1º, -38.8º, and -42.9º. As …


Stream Water And Soil Water Chemistry After The Table Mountain Wildfire, Washington, Usa, Vincent J. Roccanova Jan 2018

Stream Water And Soil Water Chemistry After The Table Mountain Wildfire, Washington, Usa, Vincent J. Roccanova

All Master's Theses

Analyses of major and trace elements, major ions, and nutrient concentrations were made to investigate how stream water and soil water chemistry changed over 16 months following the Table Mountain wildfire. Sites with different burn severity were also compared. The fire occurred in 2012 in Kittitas County, north of Ellensburg, Washington. Samples were collected at severely burned, moderately burned, and unburned field sites from within and adjacent to the wildfire perimeter. Total nitrogen concentrations increased in the second year after the fire in both the severely and moderately burned sites. In contrast, total phosphorus was variable at all three sites …


Archean Phosphorus Liberation Induced By Iron Redox Geochemistry, Barry Herschy, Sae Jung Chang, Ruth Blake, Aivo Lepland, Heather Abbott-Lyon, Jacqueline Sampson, Zachary Atlas, Terence P. Kee, Matthew A. Pasek Jan 2018

Archean Phosphorus Liberation Induced By Iron Redox Geochemistry, Barry Herschy, Sae Jung Chang, Ruth Blake, Aivo Lepland, Heather Abbott-Lyon, Jacqueline Sampson, Zachary Atlas, Terence P. Kee, Matthew A. Pasek

School of Geosciences Faculty and Staff Publications

The element phosphorus (P) is central to ecosystem growth and is proposed to be a limiting nutrient for life. The Archean ocean may have been strongly phosphorus-limited due to the selective binding of phosphate to iron oxyhydroxide. Here we report a new route to solubilizing phosphorus in the ancient oceans: reduction of phosphate to phosphite by iron(II) at low (°C) diagenetic temperatures. Reduction of phosphate to phosphite was likely widespread in the Archean, as the reaction occurs rapidly and is demonstrated from thermochemical modeling, experimental analogs, and detection of phosphite in early Archean rocks. We further demonstrate that the higher …


Occupational Seasonality And Paleoenvironmental Reconstruction At Quebrada Jaguay 280, Stephanie Melissa Gruver Jan 2018

Occupational Seasonality And Paleoenvironmental Reconstruction At Quebrada Jaguay 280, Stephanie Melissa Gruver

Graduate Research Theses & Dissertations

Quebrada Jaguay 280 (QJ-280) is one of the oldest maritime archaeological sites in the New World. Previous excavations of the southern Peruvian coastal site have dated occupation from ~13,000-8,000 cal yr BP. These excavations also determined that the occupants of the site used preferential maritime resource procurement strategies and had an interzonal connection to the highlands. In 2017 a new excavation was conducted at QJ-280 and the remains of the marine mollusk Mesodesma donacium were recovered. Geochemical examinations on the shell remains informed on the occupational seasonality of the site and reconstructed sea surface temperatures experienced off the coast of …


Hydrogen, Carbon, And Oxygen Isotopes In Prosopis Sp. Trees: A New Climate Proxy For Holocene Paleoclimate In The Atacama Desert, Chile, Elizabeth Joy Olson Jan 2018

Hydrogen, Carbon, And Oxygen Isotopes In Prosopis Sp. Trees: A New Climate Proxy For Holocene Paleoclimate In The Atacama Desert, Chile, Elizabeth Joy Olson

Graduate Research Theses & Dissertations

The spatial ubiquity of trees in terrestrial ecosystems worldwide facilitates the use of stable isotope research in tree-rings to address a wide-range of interdisciplinary questions related to climate, ecology, archaeology, and hydrology. This dissertation focuses on the development and application of Prosopis tamarugo tree-ring stable isotope records as a paleoclimate proxy for the Atacama Desert, Chile. Current paleoclimate proxies from this region lack the spatial and temporal resolution to quantify a causal mechanism for observed Holocene hydroclimate variability. P. tamarugo tree-ring isotopes provide a high-resolution proxy that facilitates the reconstruction of hydroclimate variability at a regional scale. In order to …


Investigating The Effect Of Magma Viscosity Changes On The Eruption Style Of Masaya Caldera Complex, Nicaragua, Garima Lohani Jan 2018

Investigating The Effect Of Magma Viscosity Changes On The Eruption Style Of Masaya Caldera Complex, Nicaragua, Garima Lohani

Graduate Research Theses & Dissertations

The Masaya caldera complex is a basaltic shield volcano that has produced rare basaltic Plinian eruptions (BPE) but is characterized by effusive activity in the last 6000 years. More than two million people live within a 20 km radius of the caldera. Magma viscosity plays an important role in determining the eruption style of a volcano. In this thesis, I provide the first viscosity measurements on an erupted magma composition and examine the role of magma viscosity in determining eruptive style at Masaya and in promoting BPE’s.

Viscosity experiments were conducted for a Masaya lava sample at superliquidus, subliquidus and …


Photochemical Cycling Of Reactive Oxygen Species In Hydrothermal Systems: Impacts On Biosignature Preservation, Megan A. Mave Jan 2018

Photochemical Cycling Of Reactive Oxygen Species In Hydrothermal Systems: Impacts On Biosignature Preservation, Megan A. Mave

Graduate Student Theses, Dissertations, & Professional Papers

Life originated on early Earth, despite harsh, highly reducing conditions. Life may have also emerged on early Mars, when conditions on the two planets were similar (i.e. before atmosphere loss and desiccation). NASA’s 2020 Mars rover mission aims to identify biosignatures (i.e. evidence of life) in early Martian deposits. Potential exploration sites include extinct hydrothermal springs, due to their high habitability and preservation potential. This study aims to better understand biosignature preservation in hydrothermal systems analogous to those on early Mars (i.e. reducing and Fe-rich).

Reactive oxygen species (ROS) are highly reactive molecules formed primarily by photochemical reactions. ROS are …


Using Multiple Environmental Tracers To Investigate The Relative Role Of Soil And Deep Groundwater In Stream Water Generation For A Snow-Dominated Headwater Catchment, Isabellah V. Von Trapp Jan 2018

Using Multiple Environmental Tracers To Investigate The Relative Role Of Soil And Deep Groundwater In Stream Water Generation For A Snow-Dominated Headwater Catchment, Isabellah V. Von Trapp

Graduate Student Theses, Dissertations, & Professional Papers

In this study, seasonal fluctuation of environmental tracers in stream flow, soil water, and deep bedrock groundwater were used to constrain the role of deep bedrock groundwater in streamflow generation for a mountainous headwater catchment. Synoptic measurements of stream discharge, 222Rn, specific conductivity and major ion concentrations were measured throughout the water year over a 5 km reach of Cap Wallace Creek in the Lubrecht Experimental Forest, Montana, U.S.A. with the intention of understanding groundwater – surface water interactions across spatial and temporal scales. Stage measurements were continually recorded at seven stilling well locations along the reach. Discharge measurements …


Understanding The Food Water Nexus: Characterizing The Impact Of Climatological Anomalies On Agrosystems, Patrick M. Wurster Jr. Jan 2018

Understanding The Food Water Nexus: Characterizing The Impact Of Climatological Anomalies On Agrosystems, Patrick M. Wurster Jr.

Graduate Student Theses, Dissertations, & Professional Papers

Climate variability at global and regional scales is escalating with increased atmospheric carbon and is expected to magnify the intensity and duration of meteorological extremes, especially droughts. From the many environmental stresses that diminish crop production (e.g., soil salinity, frost, soil erosion) drought is one of the most prevalent. This study focuses on the sensitivity of three key crops produced in the northwestern United States to climatological anomalies, while controlling for attribution using anomalies in price. The study differs from similar studies in that we focus on variability in production which captures both yield (tonnes/ha) and cropping area (ha), as …


Estimating Groundwater Inflow And Age Characteristics In An Alluvial Aquifer Along The Little Wind River, Wyoming, Derek Goble Jan 2018

Estimating Groundwater Inflow And Age Characteristics In An Alluvial Aquifer Along The Little Wind River, Wyoming, Derek Goble

Graduate Student Theses, Dissertations, & Professional Papers

We synoptically sampled a 2 km gaining reach of the Little Wind River in central Wyoming for 222Rn, CFCs and SF6 to determine the distributed volumes and locations of discharge and estimate alluvial groundwater age characteristics. 222Rn was sampled in the stream, shallow in-stream piezometers and nearby alluvial groundwater wells to determine the volume and spatial distribution of groundwater discharge to the river. Age tracers, CFC and SF6, sampled in the stream, shallow in-stream piezometers and in alluvial groundwater wells were then used to determine whether in-stream samples are capable of constraining the residence time distribution …


Significance Of A Non-Thermal Plasma Treatment On Ldpe Biodegradation With Pseudomonas Aeruginosa, Laurence Scally, Miroslav Gulan, Lars Weigang, Vladimir Milosavljević, Patrick J. Cullen Jan 2018

Significance Of A Non-Thermal Plasma Treatment On Ldpe Biodegradation With Pseudomonas Aeruginosa, Laurence Scally, Miroslav Gulan, Lars Weigang, Vladimir Milosavljević, Patrick J. Cullen

Articles

The use of plastics has spanned across almost all aspects of day to day life. Although their uses are invaluable, they contribute to the generation of a lot of waste products that end up in the environment and end up polluting natural habitats such as forests and the ocean. By treating low-density polyethylene (LDPE) samples with non-thermal plasma in ambient air and with an addition of ≈4% CO2, the biodegradation of the samples can be increased due to an increase in oxidative species causing better cell adhesion and acceptance on the polymer sample surface. It was, however, found that the …


Assessment Of The Disinfection Capacity And Eco-Toxicological Impact Of Atmospheric Cold Plasma For Treatment Of Food Industry Effluents, Apurva Patange, Daniela Boehm, Michelle Giltrap, Peng Lu, Patrick J. Cullen, Paula Bourke Jan 2018

Assessment Of The Disinfection Capacity And Eco-Toxicological Impact Of Atmospheric Cold Plasma For Treatment Of Food Industry Effluents, Apurva Patange, Daniela Boehm, Michelle Giltrap, Peng Lu, Patrick J. Cullen, Paula Bourke

Articles

Generation of wastewater is one of the main environmental sustainability issues across food sector industries. The constituents of food process effluents are often complex and require high energy and processing for regulatory compliance. Wastewater streams are the subject of microbiological and chemical criteria, and can have a significant eco-toxicological impact on the aquatic life. Thus, innovative treatment approaches are required to mitigate environmental impact in an energy efficient manner. Here, dielectric barrier discharge atmospheric cold plasma (ACP) was evaluated for control of key microbial indicators encountered in food industry effluent. This study also investigated the eco-toxicological impact of cold plasma …


Importance Of Hydrothermal Vents In Scavenging Removal Of 230th In The Nansen Basin, O. Valk, M. M. Rutgers Van Der Loeff, W. Geibert, S. Gdaniec, M. J.A. Rijkenberg, S. B. Moran, K. Lepore, R. L. Edwards, Y. Lu, Viena Puigcorbe Jan 2018

Importance Of Hydrothermal Vents In Scavenging Removal Of 230th In The Nansen Basin, O. Valk, M. M. Rutgers Van Der Loeff, W. Geibert, S. Gdaniec, M. J.A. Rijkenberg, S. B. Moran, K. Lepore, R. L. Edwards, Y. Lu, Viena Puigcorbe

Research outputs 2014 to 2021

In this study we present dissolved and particulate 230Th and 232Th results, as well as particulate 234Th data, obtained as part of the GEOTRACES central Arctic Ocean sections GN04 (2015) and IPY11 (2007). Samples were analyzed following GEOTRACES methods and compared to previous results from 1991. We observe significant decreases in 230Th concentrations in the deep waters of the Nansen Basin. We ascribe this nonsteady state removal process to a variable release and scavenging of trace metals near an ultraslow spreading ridge. This finding demonstrates that hydrothermal scavenging in the deep‐sea may vary on annual time …


U.S. Geological Survey (Usgs) Topographic Map Collection, Kentucky Library Research Collections Jan 2018

U.S. Geological Survey (Usgs) Topographic Map Collection, Kentucky Library Research Collections

Research Collections

This is a listing of the Topo maps housed in the KLRC; 7.5, 15 and 30 minute Kentucky and Boundary State Maps. These maps are helpful in genealogy to show how the landscape may have changed and they may have the locations of lost towns and cemeteries and indicate houses, barns, and other structures and how place names, roads, and streams changed over time.


Back Calculation Of Intelligent Compaction Data For Mechanical Properties Of Soil System, Afshin Gholamy Jan 2018

Back Calculation Of Intelligent Compaction Data For Mechanical Properties Of Soil System, Afshin Gholamy

Open Access Theses & Dissertations

For national economy, it is very important to have a reliable infrastructure. Because of this, all over the world, new roads are constantly being built and old roads are being maintained and, if necessary, expanded and/or repaired. Building a good quality road is very expensive, it costs several million dollars per kilometer. It is therefore crucial to make sure that the newly built and newly repaired roads are sufficiently stiff - so that they can withstand the predicted volume of traffic for a sufficient number of years. Current methods of estimating the stiffness are time-consuming and labor-consuming. The most accurate …


An Integrated Machine Learning Geological Field Tool In The Age Of Big Data And Drones, Guillermo Vargas Jan 2018

An Integrated Machine Learning Geological Field Tool In The Age Of Big Data And Drones, Guillermo Vargas

Open Access Theses & Dissertations

Unmanned aerial vehicles (UAVs) and machine learning are relatively new research tools in the geosciences that can be used to collect and analyze large data sets rapidly. We combine the power of rapid data collection using unmanned aerial vehicles with machine learning algorithms to develop a field-based system to identify targeted geological features. For data collection, we have used a commercial-grade UAV which carried visible-wavelength and multispectral (visible- infrared) cameras. We analyzed the data with machine learning and machine vision algorithms that can classify rock units exposed in a field area. We have identified algorithms that in previous literature have …


Mapping Complex Fold-Thrust Systems In An Inverted Rift Basin: Indio Mountains, West Texas, Samantha Ramirez Jan 2018

Mapping Complex Fold-Thrust Systems In An Inverted Rift Basin: Indio Mountains, West Texas, Samantha Ramirez

Open Access Theses & Dissertations

This study reports on new geologic mapping in the southern Indio Mountains of west Texas, where minimal research has been done since development of modern fold-thrust belt concepts. This study integrated an analysis of structure and the stratigraphy of the region. A stratigraphic column of the middle Cretaceous upper Yucca Formation was measured to 1) compare the lithology to that of the section previously measured in the hanging wall of the Squaw Peak thrust in the footwall of the Indio normal fault, 2) create informal members in the formation to aid mapping; and 3) identify previously unmapped structures in the …


Characterization And Geochemistry Of Carbonate Caprock Associated With The Gypsum Valley Salt Wall, Paradox Basin, Colorado: Implications For Understanding Lateral Caprock Emplacement, Piper Lee Poe Jan 2018

Characterization And Geochemistry Of Carbonate Caprock Associated With The Gypsum Valley Salt Wall, Paradox Basin, Colorado: Implications For Understanding Lateral Caprock Emplacement, Piper Lee Poe

Open Access Theses & Dissertations

On the northeastern side of Gypsum Valley salt wall in the Paradox Basin of Colorado, discontinuous exposures of layered gypsum and carbonate rocks were previously mapped as the contact between diapiric Paradox Formation and marine limestone of the Pennsylvanian Honaker Trail Formation. Utilizing new and existing mapping, petrographic and isotopic geochemical analyses, this study reinterprets this zone to represent lateral gypsum and carbonate caprock that formed in the Triassic during passive rise of the Gypsum Valley salt wall. Gypsum Valley lateral carbonate caprock can be distinguished from Pennsylvanian and Permian depositional carbonate strata exposed elsewhere on the salt wall by …


Geophysical Investigations Of Southcentral Alaska, Felix Dziedzorm Ziwu Jan 2018

Geophysical Investigations Of Southcentral Alaska, Felix Dziedzorm Ziwu

Open Access Theses & Dissertations

The Castle Mountain Fault (CMF) is the closest (<50 km) active fault to Anchorage, Alaska and is known to be capable of producing earthquakes of magnitude 7.0 â?? 7.1. While several mapping and trenching studies have been conducted along the CMF, geophysical investigations along the fault zone have been limited. We use over 700 recently collected, closely spaced gravity observations, in addition to existing regional gravity, aeromagnetic, seismic reflection, well log data, and geologic information, to develop new 2D models of the deeper structure of the CMF system. We developed four 2D integrated forward models across the Castle Mountain Fault. These models indicate differences between the western and eastern segments of the Castle Mountain Fault. The models show a thick sequence of Tertiary to Mesozoic sediments overlying the Peninsular terrane basement at varying depths within the area. We identified two main intrusive granitic rocks based on the varying susceptibilities. These granitic rocks share a possible fault contact with the Mesozoic sedimentary rocks. The model also shows that the CMF cuts through the Mesozoic sediments at depth. These rocks can create strong coupling along the fault and with the decreasing eastward angle of subduction, it is highly for fluid migration to the eastern edge of the subducting Yakutat microplate. Seismic events plotted along the profiles supports the Holocene motion along the western CMF (WCMF) and indicates a deeper extent of the CMF into the crust. The eastern CMF shows high rate of deformation based on the structures associated with the Mesozoic rocks.


A Combined Field, Experimental And Modeling Approach To Understand The Impacts Of Flood Irrigation On Pedogenic Caco3 And Co2 Dynamics In Drylands, Anna Cristina Ortiz Jan 2018

A Combined Field, Experimental And Modeling Approach To Understand The Impacts Of Flood Irrigation On Pedogenic Caco3 And Co2 Dynamics In Drylands, Anna Cristina Ortiz

Open Access Theses & Dissertations

Soil salinization is a global problem affecting 10% of agricultural soils, particularly in irrigated arid-lands. This study investigated salt loading through flood-irrigation, particularly of calcite (CaCO3) salt in the southwest of the United States. To evaluate the impact that flood-irrigation has on CaCO3 buildup and its effect on C-cycling, a natural soil and two agricultural soils were sampled: a pecan orchard and an alfalfa field in the El Paso, TX region. Agricultural soils in this study are flood irrigated by the Rio Grande river and by ground waters in its absence, both of which are oversaturated with calcite.

To trace …