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2019

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Articles 841 - 870 of 1657

Full-Text Articles in Earth Sciences

Petrogenesis Of The Eagle East Gabbro In Marquette County, Mi, Usa, Kevin Rupp Jun 2019

Petrogenesis Of The Eagle East Gabbro In Marquette County, Mi, Usa, Kevin Rupp

Masters Theses

The Eagle East gabbroic intrusion in Michigan’s Upper Peninsula, is a subvertical pluglike intrusion found near the base of the Eagle East Ni-Cu-PGE deposit. U-Pb baddeleyite dating of the gabbro yields an age of 1103.4 ± 1.2 Ma, suggesting formation during the early stages of the Midcontinent Rift System (MRS). Drill core observations show that the intrusion cross-cuts the eastern most portion of the Eagle East ultramafic conduit. The internal portion of the intrusion is made up of two main rock types, gabbro and gabbro norite, which consist of plagioclase (50-60%), clinopyroxene (15-25%), orthopyroxene (0-15%), olivine (0-10%), and are generally …


Behavioral Causes Of Paleopathologies In Cretaceous Edmontosaurus Annectens, Lance Formation, Wyoming, Bethania C. T. Siviero Jun 2019

Behavioral Causes Of Paleopathologies In Cretaceous Edmontosaurus Annectens, Lance Formation, Wyoming, Bethania C. T. Siviero

Loma Linda University Electronic Theses, Dissertations & Projects

The study of dinosaur paleopathology has enriched our understanding of their living conditions and their intra- and interspecific behavior. In this study, I examined lesions on bones from a monospecific bone bed (Edmontosaurus annectens) and their implications for E. annectens behavior and the ecological conditions that affected this population. The bone bed contains abundant, mostly well-preserved, scattered, and disarticulated bones, mostly representing an adult population of E. annectens. From the 3013 bones examined, 96 bones displayed genuine pathologies such as: hypertrophic ossification, healed fractures, tooth traces, idiopathic or traumatic shaft angulation, bone fusion, degenerative joint diseases, osteochondrosis, infection, neoplasm, and …


Characterization Of Cross-Bed Depositional Processes In The Coconino Sandstone, Sarah A. Maithel Jun 2019

Characterization Of Cross-Bed Depositional Processes In The Coconino Sandstone, Sarah A. Maithel

Loma Linda University Electronic Theses, Dissertations & Projects

The Permian Coconino Sandstone of northern and central Arizona is widely recognized as a classic eolian dune deposit, with conspicuous large-scale cross-beds that are interpreted as preserved dune foresets. On modern bedforms, fine-scale processes – which include grainflow, grainfall, and ripple migration – transport and deposit sediment, and these may provide useful analogs for interpreting ancient deposits. Even though the Coconino Sandstone is well known, such fine-scale process models have not been adequately developed to explain its cross-bed deposition. Furthermore, observed discrepancies between the sandstone and some eolian criteria suggest that additional study is needed to explore and refine these …


Mineralogy And Chemistry Of Rare Earth Elements In Alkaline Ultramafic Rocks And Fluorite In The Western Kentucky Fluorspar District, Warren H. Anderson Jun 2019

Mineralogy And Chemistry Of Rare Earth Elements In Alkaline Ultramafic Rocks And Fluorite In The Western Kentucky Fluorspar District, Warren H. Anderson

Report of Investigations--KGS

Rare earth elements, or REE, are used in modern society in televisions, computers, cellphones, military equipment, and smart weapons systems. These metals are also used by the medical industry in magnetic resonance imaging and in medical products.

The igneous rocks in the Western Kentucky Fluorspar District of the New Madrid Rift System are considered alkaline ultramafic rocks that are slightly enriched in REE. These rocks are rare and only occur in several hundred locations in the world. They have a complex history of emplacement, fractionation, metasomatism, and alteration, and are overprinted with Mississippi Valley-type mineralization. They are classified as lamprophyres …


An Analysis Of Differential Reflectivity Arc Characteristics In 109 Supercell Storms, Matthew Wilson Jun 2019

An Analysis Of Differential Reflectivity Arc Characteristics In 109 Supercell Storms, Matthew Wilson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Differential reflectivity (ZDR)arcs are one of the most prominent dual-polarization features of supercell storms, and are manifest as an arc-shaped area of high ZDR along a supercell’s forward flank reflectivity gradient. Since previous modelling studies have hypothesized that the magnitude of the drop-size sorting by the storm-relative wind which creates the arc signature is related to the strength of the low-level shear and SRH in a storm’s environment, the presence of a strong ZDR arc is often said to indicate that a storm may have the potential to develop strong low-level rotation and potentially become tornadic. …


Basinward Trends In Fluvial Architecture, Connectivity, And Reservoir Characterization Of The Trail Member, Ericson Sandstone, Mesaverde Group In Wyoming, Utah, And Colorado, Usa, Chelsea Anne Jolley Jun 2019

Basinward Trends In Fluvial Architecture, Connectivity, And Reservoir Characterization Of The Trail Member, Ericson Sandstone, Mesaverde Group In Wyoming, Utah, And Colorado, Usa, Chelsea Anne Jolley

Theses and Dissertations

The Late Cretaceous Trail Member of the Ericson Sandstone represents a regionally extensive fluvial system that transported sediments from the Sevier fold and thrust belt and Uinta Mountain uplift to the Western Interior Seaway. The Trail Member is a petroleum reservoir target that has unpredictable production rates due to the unknown behavior and connectivity of channel sandstones. The abundant outcrop, wellbore, and core data available allows for a comprehensive analysis of how the fluvial architecture, connectivity, and reservoir quality change along 65 km of depositional dip. Observations made at Flaming Gorge and Clay Basin (most landward field locations) suggest a …


Williston Basin Water Treatment Technology Test Bed, University Of North Dakota. Energy And Environmental Research Center Jun 2019

Williston Basin Water Treatment Technology Test Bed, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about Energy & Environmental Research Center plan to pilot-test technology to treat high-TDS (total dissolved solids) water. Includes a description of proposed water treatment technology and plan for the testing process. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]


Soil Capability Assessment For Expanding Irrigated Agriculture In The Dinner Hill Focus Area, Midlands, Western Australia, Edward Arnold Griffin, Angela Stuart-Street, Leon Van Wyk, Peter Tille Jun 2019

Soil Capability Assessment For Expanding Irrigated Agriculture In The Dinner Hill Focus Area, Midlands, Western Australia, Edward Arnold Griffin, Angela Stuart-Street, Leon Van Wyk, Peter Tille

Resource management technical reports

The Midlands groundwater and land assessment is a $4.7 million Water for Food project using Royalties for Regions funding. It is seeking to confirm groundwater availability in focus areas that may form precincts of 2000–3000ha suitable for intensive irrigated horticulture. The Dinner Hill focus area is one of these.

The Dinner Hill focus area covers about 50 200ha to the north-west of Moora and north of Dandaragan, in the Midlands area of Western Australia. This report provides details of the soil-landscapes, land capability and land management units for the Dinner Hill focus area.

We reviewed existing soil-landscape mapping for the …


Ages Of Prehistoric Earthquakes On The Banning Strand Of The San Andreas Fault, Near North Palm Springs, California, Bryan Castillo Jun 2019

Ages Of Prehistoric Earthquakes On The Banning Strand Of The San Andreas Fault, Near North Palm Springs, California, Bryan Castillo

Electronic Theses, Projects, and Dissertations

We studied a paleoseismic trench that was excavated across the Banning strand of the San Andreas Fault by Petra Geosciences (33.9172°, -116.538°). The trench exposed a ~40 m wide fault zone in interbedded alluvial sand gravel, silt and clay deposits. We present the first paleoseismic record for the Banning strand of the southern San Andreas Fault. The most recent event occurred sometime between 730 and 950 cal BP, potentially coincident with rupture of the San Gorgonio Pass thrust. We interpret that five earthquakes have occurred since 3.3-2.5 ka and eight earthquakes have likely occurred since 7.1-5.7 ka. It is possible …


Chronostratigraphic Correlation Of The Burnt Bluff Group Across The Michigan Basin, Usa, Mohammed A. Al-Musawi Jun 2019

Chronostratigraphic Correlation Of The Burnt Bluff Group Across The Michigan Basin, Usa, Mohammed A. Al-Musawi

Masters Theses

In the Michigan Basin, the Burnt Bluff Group (BBG) is lower Middle Silurian in age (Llandovery), and is composed of limestones and dolostones. The BBG is bounded above by the Schoolcraft Formation and below by the Cabot Head Shale. The BBG in northern Lower Michigan is composed of three formations, including the Lime Island, Byron, and Hendricks, which reflect deposition on a broad shallow marine shelf. In contrast, the BBG in central Michigan is composed of a single lithologic unit called informally the “undifferentiated BBG (UD-BBG),” which reflects deposition in a deeper marine basin. Lithostratigraphically, the three formations in the …


Next-Generation Rainfall Idf Curves For The Virginian Drainage Area Of Chesapeake Bay, Xixi Wang, Xiaomin Yang, Zhaoyi Cai Jun 2019

Next-Generation Rainfall Idf Curves For The Virginian Drainage Area Of Chesapeake Bay, Xixi Wang, Xiaomin Yang, Zhaoyi Cai

Civil & Environmental Engineering Faculty Publications

Probability-based intensity-duration-frequency IDF curves are needed but currently lacking for Department of Defense DoD to construct and manage its infrastructure in changing climate. The objectives of this project were to 1 develop an innovative approach for considering rainfall non-stationarity in developing such IDF curves and 2 apply this approach to the state of Virginia. In this regard, the observed data on 15-min rainfall at 57 gauges and the precipitations projected by twelve pairs of Regional Climate Model RCM and Global Circulation Model GCM were used. For a given gauge or watershed, in terms of fitting the empirical exceedance probabilities, a …


Lithospheric Structure And Evolution Of Southern Africa: Constraints From Joint Inversion Of Rayleigh Wave Dispersion And Receiver Functions, Tuo Wang, Stephen S. Gao, Yuhang Dai, Qiuyue Yang, Kelly H. Liu Jun 2019

Lithospheric Structure And Evolution Of Southern Africa: Constraints From Joint Inversion Of Rayleigh Wave Dispersion And Receiver Functions, Tuo Wang, Stephen S. Gao, Yuhang Dai, Qiuyue Yang, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We conduct a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion from both ambient noise and earthquakes using data from 79 seismic stations in southern Africa, which is home to some of the world's oldest cratons and orogenic belts. The area has experienced two of the largest igneous activities in the world (the Okavango dyke swarm and Bushveld mafic intrusion) and thus is an ideal locale for investigating continental formation and evolution. The resulting 3-D shear wave velocities for the depth range of 0—100Â km and crustal thickness measurements show a clear spatial correspondence with known …


Landscape Grain Effect In Yancheng Coastal Wetland And Its Response To Landscape Changes, Peng Tian, Luodan Cao, Jialin Li, Ruiliang Pu, Xiaoli Shi, Lijia Wang, Ruiqing Liu, Hao Xu, Chen Tong, Zijing Zhou, Shuyao Shao Jun 2019

Landscape Grain Effect In Yancheng Coastal Wetland And Its Response To Landscape Changes, Peng Tian, Luodan Cao, Jialin Li, Ruiliang Pu, Xiaoli Shi, Lijia Wang, Ruiqing Liu, Hao Xu, Chen Tong, Zijing Zhou, Shuyao Shao

School of Geosciences Faculty and Staff Publications

The landscape grain effect reflects the spatial heterogeneity of a landscape and it is used as a research core of landscape ecology. The landscape grain effect can be used to not only explore spatiotemporal variation characteristics of a landscape pattern, but also to disclose variation laws of ecological structures and functions of landscapes. In this study, the sensitivity of landscape pattern indexes to grain sizes 50–1000 m was studied based on landscape data in Yancheng Coastal Wetland acquired in 1991, 2000, 2008, and 2017. Response of the grain effect to landscape changes was analyzed and an optimal grain size for …


Mercury Cycling In The North Pacific Subtropical Gyre As Revealed By Mercury Stable Isotope Ratios, Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg May 2019

Mercury Cycling In The North Pacific Subtropical Gyre As Revealed By Mercury Stable Isotope Ratios, Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg

Faculty Publications

The oceans are an important global reservoir for mercury (Hg), and marine fish consumption is the dominant human exposure pathway for its toxic methylated form. A more thorough understanding of the global biogeochemical cycle of Hg requires additional information on the mechanisms that control Hg cycling in pelagic marine waters. In this study, Hg isotope ratios and total Hg concentrations are used to explore Hg biogeochemistry in oligotrophic marine environments north of Hawaii. We present the first measurements of the vertical water column distribution of Hg concentrations and the Hg isotopic composition in precipitation, marine particles, and zooplankton near Station …


Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge May 2019

Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge

Celebration of Learning

Taxonomic biodiversity, measured by counting the number of species present in a given area, is the most common method of capturing ecosystem biodiversity in recent and ancient environments. While this method is widely accepted, it is limited by poor preservation and identification of many individuals, making it impossible to include every species within an ecosystem and resulting in the loss of some diversity information. To address this issue, we measured the genetic biodiversity (in which species are determined based on sequencing of their DNA) of shallow marine ecosystems by extracting and sequencing the 18S ribosomal gene from bulk carbonate sediment …


Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig May 2019

Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig

Celebration of Learning

The subduction of the Nazca Plate under the South American Plate has led to the uplift of the majority of the Andes Mountains, but in Ecuador, the Nazca Plate subducts underneath the North Andes Plate, which then collides with the South American Plate. This tectonic setting has formed two parallel mountain chains as well as a complex series of basins between them. However, the formations that make up these basins are poorly understood. This study focuses on the Chinchín Formation, an ~3.5 km thick, volcanic formation that serves as the bedrock of the Quingeo Basin in southern Ecuador. This study …


Seismic Observations Of Crevasse Growth Following Rain-Induced Glacier Acceleration, Haupapa/Tasman Glacier, New Zealand, Samuel Taylor-Offord, Huw Horgan, John Townend, J. Paul Winberry May 2019

Seismic Observations Of Crevasse Growth Following Rain-Induced Glacier Acceleration, Haupapa/Tasman Glacier, New Zealand, Samuel Taylor-Offord, Huw Horgan, John Townend, J. Paul Winberry

All Faculty Scholarship for the College of the Sciences

Changing rates of water input can affect both the flow of glaciers and ice sheets and their propensity to crevasse. Here we examine geodetic and seismic observations during two substantial (10–18-times background velocity) rain-induced glacier accelerations at Haupapa/Tasman Glacier, New Zealand. Changes in rain rate result in glacier acceleration and associated uplift, which propagate down-glacier. This pattern of acceleration results in a change to the strain rate field, which correlates with an order of magnitude increase in the apparent seismicity rate and an overall down-glacier migration in located seismicity. After each acceleration event the apparent seismicity rate decreases to below …


Using Satellite-Based Hydro-Climate Variables And Machine Learning For Streamflow Modeling At Various Scales In The Upper Mississippi River Basin, Dongjae Kwon May 2019

Using Satellite-Based Hydro-Climate Variables And Machine Learning For Streamflow Modeling At Various Scales In The Upper Mississippi River Basin, Dongjae Kwon

Theses and Dissertations

Streamflow data are essential to study the hydrologic cycle and to attain appropriate water resource management policies. However, the availability of gauge data is limited due to various reasons such as economic, political, instrumental malfunctioning, and poor spatial distribution. Although streamflow can be simulated by process-based and machine learning approaches, applicability is limited due to intensive modeling effort, or its black-box nature, respectively. Here, we introduce a machine learning (Boosted Regression Tree (BRT)) approach based on remote sensing data to simulate monthly streamflow for three of varying sizes watersheds in the Upper Mississippi River Basin (UMRB). By integrating spatial land …


Assessment Of Agricultural Drought Considering The Hydrological Cycle And Crop Phenology In The Korean Peninsula, Chul-Hee Lim, Seung Hee Kim, Jong Ahn Chun, Menas Kafatos, Woo-Kyun Lee May 2019

Assessment Of Agricultural Drought Considering The Hydrological Cycle And Crop Phenology In The Korean Peninsula, Chul-Hee Lim, Seung Hee Kim, Jong Ahn Chun, Menas Kafatos, Woo-Kyun Lee

Mathematics, Physics, and Computer Science Faculty Articles and Research

Hydrological changes attributable to global warming increase the severity and frequency of droughts, which in turn affect agriculture. Hence, we proposed the Standardized Agricultural Drought Index (SADI), which is a new drought index specialized for agriculture and crops, and evaluated current and expected droughts in the Korean Peninsula. The SADI applies crop phenology to the hydrological cycle, which is a basic element that assesses drought. The SADI of rice and maize was calculated using representative hydrological variables (precipitation, evapotranspiration, and runoff) of the crop growing season. In order to evaluate the effectiveness of SADI, the three-month Standardized Precipitation Index, which …


Understanding The Relationship Between Sedimentation, Vegetation And Topography In The Tijuana River Estuary, San Diego, Ca., Darbi Berry May 2019

Understanding The Relationship Between Sedimentation, Vegetation And Topography In The Tijuana River Estuary, San Diego, Ca., Darbi Berry

Theses

The aim of this study is to identify and characterize key geomorphic properties and relationships within the study site, the Tijuana River Estuary. This is a first step in contributing data to and assisting current and future restoration projects in employing a holistic management approach. The study identifies specific physical parameters, grain size and metal concentrations, within the estuary whose relationship to one another is not mutually exclusive and therefore should be addressed in tandem. This study also tests a remote sensing method for use as a tool for monitoring habitat changes in the estuary.


Managing Agroecosystems For Soil Microbial Carbon Use Efficiency: Ecological Unknowns, Potential Outcomes, And A Path Forward, Cynthia M. Kallenbach, Matthew D. Wallenstein, Meagan E. Schipanksi, A. Stuart Grandy May 2019

Managing Agroecosystems For Soil Microbial Carbon Use Efficiency: Ecological Unknowns, Potential Outcomes, And A Path Forward, Cynthia M. Kallenbach, Matthew D. Wallenstein, Meagan E. Schipanksi, A. Stuart Grandy

Faculty Publications

Agricultural systems are increasingly managed for improving soil carbon (C) accumulation. However, there are limits to C returns in agricultural systems that constrain soil C accumulation capacity. Increasing the efficiency of how soil microbes process C is gaining interest as an important management strategy for increasing soil C and is a key feature of soil C dynamics in many new microbial-explicit models. A higher microbial C use efficiency (CUE) may increase C storage while reducing C system losses and is a fundamental trait affecting community assembly dynamics and nutrient cycling. However, the numerous ecological unknowns influencing CUE limit our ability …


Understanding The Bioavailability Of Pyrethroids In The Aquatic Environment Using Chemical Approaches, Zhijiang Lu, Jay Gan, Xinyi Cui, Laura Delgado-Moreno, Kunde Lin May 2019

Understanding The Bioavailability Of Pyrethroids In The Aquatic Environment Using Chemical Approaches, Zhijiang Lu, Jay Gan, Xinyi Cui, Laura Delgado-Moreno, Kunde Lin

Environmental Science and Geology Faculty Research Publications

Pyrethroids are a class of commonly used insecticides and are ubiquitous in the aquatic environment in various regions. Aquatic toxicity of pyrethroids was often overestimated when using conventional bulk chemical concentrations because of their strong hydrophobicity. Over the last two decades, bioavailability has been recognized and applied to refine the assessment of ecotoxicological effects of pyrethroids. This review focuses on recent advances in the bioavailability of pyrethroids, specifically in the aquatic environment. We summarize the development of passive sampling and Tenax extraction methods for assessing the bioavailability of pyrethroids. Factors affecting the bioavailability of pyrethroids, including physicochemical properties of pyrethroids, …


Middle Miocene To Holocene History Of The Delacroix Island Fault System, Jarrett Leigh Levesh May 2019

Middle Miocene To Holocene History Of The Delacroix Island Fault System, Jarrett Leigh Levesh

LSU New Orleans Theses and Dissertations

An in-depth field study of the Delacroix Island producing field illustrates the evolution of the east-trending Delacroix Island Fault during the last 13 My. Well log correlations and 3-D seismic interpretation of 22 subsurface bio-stratigraphic horizons across the fault reveal variable stratigraphic thicknesses and displacement. Wells, with well log curve data as shallow as 31 m (100 ft) below the surface, were used to calculate interval thicknesses, expansion indices, sediment accumulation rates, burial history and magnitudes of displacement. Through these analyses, a correlation was found between the positioning of ancient Miocene depocenters over Delacroix Island and a period of increased …


Geomorphic And Temporal Evolution Of A Mississippi Delta Flanking Barrier Island: Grand Isle, La, Julie A. Torres May 2019

Geomorphic And Temporal Evolution Of A Mississippi Delta Flanking Barrier Island: Grand Isle, La, Julie A. Torres

LSU New Orleans Theses and Dissertations

Optically stimulated luminescence (OSL) dating beach ridge sediments is one method for resolving barrier island growth at intermediate scales (decades-centuries), information that is lacking for Louisiana. This research combines OSL, GPR, aerial imagery, and cores to document temporal and spatial evolution of a Louisiana barrier island.

Grand Isle is composed of beach ridges organized in distinct, unconformable sets that began forming 0.75 ka until 0.575 ka when deposition ceased, the ridges were partially eroded, and deposition resumed in a more eastward direction. The central ridges formed between 370±30 and 170±10 years ago at a rate of one ridge every 11.6 …


Seamless Lidar Surveys Reveal Rates And Patterns Of Subsidence In The Mississippi River Delta, Celeste E. Woock May 2019

Seamless Lidar Surveys Reveal Rates And Patterns Of Subsidence In The Mississippi River Delta, Celeste E. Woock

LSU New Orleans Theses and Dissertations

Light Detection and Ranging (Lidar) data are used to report the temporal and spatial patterns of subsidence as well as the potential contributors to subsidence within the Barataria and Terrebonne Bays. In recent decades, subsidence in southeast Louisiana has become a topic of substantial and growing concern to the scientific community, the local residents, and all those invested in the region. Lidar data were acquired from the United States Geological Survey (USGS) and the LSU Center for Geoinformatics. The data has been manipulated to map the differenced Lidar, complete an instantaneous slope analysis, and determine the thickness of the Holocene …


Substrate Quality And Concentration Control Decomposition And Microbial Strategies In A Model Soil System, Jorg Schnecker, Timothy Bowles, Erik A. Hobbie, Richard G. Smith, A. Stuart Grandy May 2019

Substrate Quality And Concentration Control Decomposition And Microbial Strategies In A Model Soil System, Jorg Schnecker, Timothy Bowles, Erik A. Hobbie, Richard G. Smith, A. Stuart Grandy

Faculty Publications

Soil carbon models typically scale decomposition linearly with soil carbon (C) concentration, but this linear relationship has not been experimentally verified. Here we investigated the underlying biogeochemical mechanisms controlling the relationships between soil C concentration and decomposition rates. We incubated a soil/sand mixture with increasing amounts of finely ground plant residue in the laboratory at constant temperature and moisture for 63 days. The plant residues were rye (Secale cereale, C/N ratio of 23) and wheat straw (Triticum spp., C/N ratio of 109) at seven soil C concentrations ranging from 0.38 to 2.99%. We measured soil respiration, dissolved organic carbon (DOC) …


Effectiveness Of Different Approaches To Arsenic Mitigation Over 18 Years In Araihazar, Bangladesh: Implications For National Policy, Nadia B. Jamil, Huan Feng, Kazi Matin Ahmed, Imtiaz Choudhury, Prabhat Barnwal, Alexander Van Geen May 2019

Effectiveness Of Different Approaches To Arsenic Mitigation Over 18 Years In Araihazar, Bangladesh: Implications For National Policy, Nadia B. Jamil, Huan Feng, Kazi Matin Ahmed, Imtiaz Choudhury, Prabhat Barnwal, Alexander Van Geen

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

About 20 million rural Bangladeshis continue to drink well water containing >50 μg/L arsenic (As). This analysis argues for reprioritizing interventions on the basis of a survey of wells serving a population of 380,000 conducted one decade after a previous round of testing overseen by the government. The available data indicate that testing alone reduced the exposed population in the area in the short term by about 130,000 by identifying the subset of low As wells that could be shared at a total cost of impact, as 60,000 exposed inhabitants lowered their exposure by installing new wells to tap intermediate …


Tidal And Spatial Variability Of Flow Speed And Seismicity Near The Grounding Zone Of Beardmore Glacier, Antarctica, Jade Cooley, J. Paul Winberry, Michelle Koutnik, Howard Conway May 2019

Tidal And Spatial Variability Of Flow Speed And Seismicity Near The Grounding Zone Of Beardmore Glacier, Antarctica, Jade Cooley, J. Paul Winberry, Michelle Koutnik, Howard Conway

All Faculty Scholarship for the College of the Sciences

GPS measurements of tidal modulation of ice flow and seismicity within the grounding zone of Beardmore Glacier show that tidally induced fluctuations of horizontal flow are largest near the grounding line and decrease downstream. Seismic activity is continuous, but peaks occur on falling and rising tides. Beamforming methods reveal that most seismic events originate from two distinct locations, one on the grid-north side of the grounding zone, and one on the grid-south side. The broad pattern of deformation generated as Beardmore Glacier merges with the Ross Ice Shelf results in net extension along the grid-north side of the grounding zone …


Geomorphic Effects Of Engineered Log Structures And Response To A Catastrophic Flood Event In A Missouri Ozarks River, Joseph S. Nash May 2019

Geomorphic Effects Of Engineered Log Structures And Response To A Catastrophic Flood Event In A Missouri Ozarks River, Joseph S. Nash

Graduate Theses/Dissertations

Engineered log structures (ELSs) composed of local tree logs have been installed in river channels throughout the Pacific Northwest as a restoration technique. However, ELSs have not been tested for use in the Ozark Highlands until recently. In October 2016 the U.S. Forest Service installed four ELSs to stabilize banks along the North Fork of the White River in Ozark County, Missouri. The purpose here is to report on monitoring studies of pre- and post-restoration channel conditions and to assess geomorphic responses to floods. Over a ten-day period in April 2017 there were two bankfull floods, and on April 30, …


Petrology And Geochemistry Of The Bearwallow Mountain Andesite, Mogollon-Datil Volcanic Field, New Mexico, Conor Lee O'Dowd May 2019

Petrology And Geochemistry Of The Bearwallow Mountain Andesite, Mogollon-Datil Volcanic Field, New Mexico, Conor Lee O'Dowd

Graduate Theses/Dissertations

The Mogollon-Datil volcanic field (MDVF), located in southern New Mexico, is the result of episodic volcanism and the transition between arc and rift magmatism. The MDVF has been the focus of several mapping, stratigraphic, petrologic, geochronological, and geochemical studies to understand the complete volcanic and tectonic history. However, the majority of previous studies lack geochemical analyses on intermediate composition volcanic rocks, giving more attention to the large-volume ignimbrites and rhyolite flows as well as the minor basalt flows that occurred between 36 and 20 Ma. I present new whole-rock major- and trace-element analyses and petrographic textures on one of the …