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Articles 181 - 210 of 237
Full-Text Articles in Earth Sciences
The Impact Of Sprawl On Transportation Energy Copnsumption And Transportation Carbon Footprint In Large U.S. Cities, Leila Ahmadi
The Impact Of Sprawl On Transportation Energy Copnsumption And Transportation Carbon Footprint In Large U.S. Cities, Leila Ahmadi
Earth & Environmental Sciences Dissertations - Archive
Today, climate change and energy shortage are major concerns among scientists, politicians, and economists. For decades in the U.S., emphasis has been placed on improving energy efficiency through technological advances. However, most of these technologies are in the initial phases of development, while energy consumption continues to increase at a rapid pace. In order to solve this dilemma, there is a need to develop a faster and more effective approach for controlling the rates of energy consumption and demand. Transportation consumes more energy than other energy-dependent activities, such as those in the industrial, residential, and commercial sectors of the economy. …
Biomarkers: Review And Application To The Eagle Ford Shale Formation, Ugochukwu Ononogbu
Biomarkers: Review And Application To The Eagle Ford Shale Formation, Ugochukwu Ononogbu
Earth & Environmental Sciences Theses - Archive
Biomarkers have become an integral part of oil exploration. Gas Chromatography (-Mass Spectrometry) was performed to an oil sample to acquire biomarkers from the sample.The presence, lack of, or abundance of a given compound (or biomarker) in the geochemicalresults of an oil sample depict(s) a property or properties of the source rock and the oil. Forexample, the abundance of pristane and lack of phytane in an oil sample are characteristic ofshale source rock, and the results from the Eagle Ford shale formation show a high pristane tophytane ratio.The Eagle Ford shale formation is cretaceous in age; the presence and absence …
A Late Holocene Meander-Braid Transition Of The Lower Missouri River Valley, Michele Viola Kashouh
A Late Holocene Meander-Braid Transition Of The Lower Missouri River Valley, Michele Viola Kashouh
Earth & Environmental Sciences Theses - Archive
Historically, the Lower Missouri River is known for being a temperate river that constantly and quickly reworks its floodplain with a braided network of channels; however, the river only recently became braided. Ox-bow lakes and landscape features resembling highly sinuous meandering loops mark the floodplain of the lower Missouri River Valley as scars of what was once a fully meandering Missouri River. The unanswered question then is, when did the lower Missouri River system change from meandering to braided? To answer this question we compared a series of newly created allostratigraphic maps of the lower Missouri River valley floor to …
Microfaunal Assemblages Of The Placid Shale (Missourian, Upper Pennsylvanian), Brazos River Valley, North-Central Texas, Brittany E. Meagher
Microfaunal Assemblages Of The Placid Shale (Missourian, Upper Pennsylvanian), Brazos River Valley, North-Central Texas, Brittany E. Meagher
Earth & Environmental Sciences Theses - Archive
The Pennsylvanian and lowermost part of the Permian strata in North-Central Texas is assigned to the Strawn, Canyon, and Cisco Groups. The Canyon Group is approximately equivalent to the middle-upper part of the Missourian (Upper Pennsylvanian) and crops out in the Brazos River valley in a generally northeast-southwest strip across Palo Pinto and Jack counties. The Canyon Group is subdivided into seven formations that contain several cycles of well-known clastic and carbonate units. The Placid Shale, one of the clastic units within the Canyon Group, consists of two cycles of gray, brown, olive sandstone/siltstone/mudstone with few thin limestone beds. It …
High Resolution Geochemistry Of The Cretaceous Eagle Ford Shale, Bee County, Texas, Lisa Michelle Moran
High Resolution Geochemistry Of The Cretaceous Eagle Ford Shale, Bee County, Texas, Lisa Michelle Moran
Earth & Environmental Sciences Theses - Archive
The Eagle Ford Formation of Bee County, Texas is a sporadically laminated carbonaceous dark mudrock. The depositional area of the Eagle Ford Formation stretches across the state of Texas in a northeast-southwest trend. Early studies of the Eagle Ford found the deposits to be rich in organic material but could not fully describe the formation due to the lack of outcrop exposure. Recent studies of the Eagle Ford Formation have begun to explore the sub-surface nature of the formation. Geochemical analyses of the J.A. Leppard #1 core from the southwestern portion of the formation was conducted to further constrain the …
Growth Rates Of The Harmful Alga Prymnesium Parvum: An Attempt To Identify The Salinity Threshold For Algal Blooms, James William Cody Black
Growth Rates Of The Harmful Alga Prymnesium Parvum: An Attempt To Identify The Salinity Threshold For Algal Blooms, James William Cody Black
Earth & Environmental Sciences Theses - Archive
Harmful algal blooms due to Prymnesium parvum have occurred in Texas for nearly three decades in waters of moderate salinity. More recently, blooms have occurred in locations such as West Virginia, in waters of very low salinity where pollution discharges are suspected to have increased salinity to levels that support growth of P. parvum. These observations raise the question, what is the lowest salinity at which this species of algae can cause toxic fish kills? Previous research based on field observations has suggested a salinity threshold of about 1.5 PSU for occurrence of blooms in Texas reservoirs in winter. Other …
Chemostratigraphy, Paleoceanography, And Sequence Stratigraphy Of The Pennsylvanian-Permian Section In The Midland Basin Of West Texas With Focus On The Wolfcamp Formation, Milton Cortez
Earth & Environmental Sciences Theses - Archive
The late Pennsylvanian to early Permian rocks (Wolfcampian and Leonardian) of the Midland Basin represent a single lithologic unit composed primarily of calcareous mudrocks, siliceous mudrocks, muddy carbonate-clast conglomerates, and skeletal packstones/grainstones at the approximate depositional center located in Reagan County, Texas. Pure versions of these lithologic end-members are discretely distributed among a multitude of transitional lithofacies. The Midland Basin evolved in the foreland of the Ouachita Fold-belt from Mississippian to early Permian time along-side several sub-basins of the Permian Basin. These basins were formed by disseverance and uplift associated with the continental collision of Laurasia and Gondwana to form …
Chemostratigraphy And Paleoenvironmental Significance Of The Pennsylvanian Smithwick Formation, Northern Llano Uplift Region, Texas, Rene Bernabe Ovalle-Rauch
Chemostratigraphy And Paleoenvironmental Significance Of The Pennsylvanian Smithwick Formation, Northern Llano Uplift Region, Texas, Rene Bernabe Ovalle-Rauch
Earth & Environmental Sciences Theses - Archive
The Early Pennsylvanian (Bashkirian-Moscovian) Smithwick Formation of Central Texas has been previously described as a marine transgressive, fairly homogeneous and fine-grained dark shale sequence with varying local depositional lithofacies. The deposition of the Smithwick shale through the southern margin of the Fort Worth Basin (FWB) has shown large variability in thickness and deposition style. Lithological heterogeneity of the bounding units throughout the basin is inferred to be the result of a combination of depositional, tectonic and eustatic variations. Regional structural instability from Late Mississippian to Early Pennsylvanian is linked to the reactivation of the Ouachita geosyncline and thrust front, causing …
An Atlas Of Cenozoic Climate Zones, Clinton Whitaker Crowley
An Atlas Of Cenozoic Climate Zones, Clinton Whitaker Crowley
Earth & Environmental Sciences Theses - Archive
This atlas illustrates global climatic zones in five major turning points of Cenozoic climate history: the K/T, the Paleocene/Eocene Thermal Maximum (PETM), the Eocene/Oligocene Transition (EOT), the Late Miocene (Messinian), and the Last Glacial Maximum (LGM). The mapswere produced from a combination of climate simulations (FOAM, CCSM, ECHAM, BESTGUESS, GENESIS and others) and climatic zone reconstructions based on lithologic data. Paleogeographic base maps of the time intervals from the PALEOMAP Project were then illustrated with an artist's rendition of the Earth's appearance. The color scheme was based onNASA's Blue Marble images. An overview of the conditions that shaped global climate …
Numerical Simulation Of The Base-Level Buffers And Buttresses Conceptual Model Of Fluvial Systems, Ronnie Tooyak Tingook
Numerical Simulation Of The Base-Level Buffers And Buttresses Conceptual Model Of Fluvial Systems, Ronnie Tooyak Tingook
Earth & Environmental Sciences Dissertations - Archive
A Buffer in fluvial stratigraphy is a potentiometric surface which defines either: a) the lowest possible depth to which streams will incise; or b) the maximum elevation to which aggradation will occur; together, these surfaces define a buffer zone. The buffer zone is tied down profile to a Buttress which defines base level for the system. A buttress shift, i.e., change in sea-level or shoreline-trajectory sensu (Catuneanu et al., 2009), will effect a change as to where the buffer zone exists for a fluvial system at a particular point in time. These terms were all introduced in (Holbrook et al., …
On-Road Measurement Of Nox And Co₂ Emissions From Biodiesel Produced From Different Feedstocks, Natchanok Pala-En
On-Road Measurement Of Nox And Co₂ Emissions From Biodiesel Produced From Different Feedstocks, Natchanok Pala-En
Earth & Environmental Sciences Dissertations - Archive
Biodiesel has generated increased interest in the US and elsewhere recently as an alternative to petroleum-derived diesel. Because it can be produced from domestic feedstocks such as soybeans, canola oil, and even recycled cooking oil, biodiesel can help reduce dependence on foreign petroleum. Due to its high oxygen content, biodiesel typically burns more completely than petroleum diesel, and thus has lower emissions of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM). However, biodiesel may increase or decrease nitrogen oxide (NOx) and carbon dioxide (CO₂) emissions, depending on engine type, test cycle, and biodiesel feedstock. Therefore, the purpose of this …
Predicting The Ancient Occurrence Of Coal Deposits Using Paleoclimate Modelling, Mandi Beck
Predicting The Ancient Occurrence Of Coal Deposits Using Paleoclimate Modelling, Mandi Beck
Earth & Environmental Sciences Theses - Archive
Coals are accumulated and consolidated remains of plant material, which means that in order to form coals, a certain amount of annual precipitation is required. This study uses paleo-precipitation data obtained from Fast Ocean Atmosphere Model (FOAM) and predicts where paleo-coal deposits might occur. All predicted coal localities were plotted on paleogeographic reconstructions (obtained from the PALEOMAP Project) for thirteen time intervals from the Early Carboniferous to present. Once these predicted coal deposits were plotted, observed coals from the Boucot et al., 2012 database were then plotted on the same reconstructed basemaps. The predicted coal deposits were then compared with …
Chemostratigraphy And Geochemical Constraints On The Deposition Of The Bakken Formation, Williston Basin, Eastern Montana And Western North Dakota, David Nyrup Maldonado
Chemostratigraphy And Geochemical Constraints On The Deposition Of The Bakken Formation, Williston Basin, Eastern Montana And Western North Dakota, David Nyrup Maldonado
Earth & Environmental Sciences Theses - Archive
The late Devonian-early Mississippian Bakken Formation was deposited in a structural-sedimentary intracratonic basin that extends across a large part of modern day North Dakota, eastern Montana, and the southern portion of Canada's Saskatchewan Province. The deposition of the Bakken Formation occurred during a fascinating period of geologic time that is linked to one of the five major mass extinctions. The occurrences of these mass extinctions are recorded worldwide as organic rich mud rocks similar to the ones found in the Bakken Formation. Collectively, the Bakken Formation consists of a middle dolomitic siltstone that is representative of a transgressive deposit and …
Heavy Metal Contamination Of Road Dust In Lanzhou, China, Michael Hiett
Heavy Metal Contamination Of Road Dust In Lanzhou, China, Michael Hiett
Earth & Environmental Sciences Theses - Archive
Road dusts were collected from the streets of the city of Lanzhou, the capital and largest city of Gansu Province in Northwest China. The potential health hazard posed by contaminated road dusts may be considerable for certain sensitive populations. Specifically young children who, while exploring their environment by mouthing and touching, may inadvertently ingest polluted soils and dusts through hand-to-mouth-activity, and through mouthing contaminated objects. Lanzhou, once ranked as one of the 10 most polluted cities in the world, clearly has, in all likelihood many locales with elevated levels of pollutants in various environmental media (e.g., air, water, soil and …
Surface Lineaments And Lithofacies Distribution Of The Tyler Formation In Southwestern North Dakota, Nicolas Beltran Guerrero
Surface Lineaments And Lithofacies Distribution Of The Tyler Formation In Southwestern North Dakota, Nicolas Beltran Guerrero
Earth & Environmental Sciences Theses - Archive
The purpose of this study is to investigate whether a correlation exists between surface lineaments and lithofacies distribution of the Pennsylvanian Tyler Formation in the southwest portion of North Dakota of the Williston Basin. If a cost-effective technique to locate preserved fluvial sandstone bodies can be developed, the Tyler Formation has the potential to be a productive hydrocarbon exploration target. Many intercratonic sedimentary basins, such as the Williston Basin, exhibit nearly orthogonal surface lineaments. In the case of the Cooper Basin in Australia, lineament analysis helped locate areas where Proterozoic rocks are fractured and filled with quartz veins containing precious …
Integrated Chemostratigraphy And Paleoceanography Of The Mississippian Barnett Formation, Krystin Chantel Robinson
Integrated Chemostratigraphy And Paleoceanography Of The Mississippian Barnett Formation, Krystin Chantel Robinson
Earth & Environmental Sciences Theses - Archive
The Barnett Formation was deposited on a gently sloping marine margin that ultimately became the Fort Worth Basin (FWB), a foreland basin that evolved during the late Paleozoic Era. The FWB formed as a result of the early Ouachita Orogeny, due to the collision of Laurasia and Gondwana. The Mississippian Barnett Formation is an organic-rich lithologic unit composed primarily of laminated siliceous mudrock with some calcareous mudrock intervals. The objective of the project is to develop and interpret stratigraphic changes in the geochemistry of the Barnett Formation for the purposes of understanding the paleoceanography of the northernmost Fort Worth Basin, …
An Updated Gps Velocity Field For Puerto Rico And The Virgin Islands: Constraints On Tectonic Setting And Internal-Deformation, Desmond Kelvin Ihemedu
An Updated Gps Velocity Field For Puerto Rico And The Virgin Islands: Constraints On Tectonic Setting And Internal-Deformation, Desmond Kelvin Ihemedu
Earth & Environmental Sciences Theses - Archive
Puerto Rico and the northern Virgin Islands define the eastern end of the Greater Antilles, while the Puerto Rico trench and the Muertos Trough define the northern and the southern limits of the North American - Caribbean plate boundary zone. Three microplates have been defined: (1) Gonave, to the west; (2) Hispaniola, at the center; and (3) Puerto Rico and the northern Virgin Islands (PRVI) at the eastern end. Global Positioning System (GPS) geodesy was previously conducted in this region from 1994 to 2003. It was concluded that the locus of the highest permissible on-surface deformation in Puerto Rico and …
Predicting The Ancient Occurrence Of Evaporites Using Paleoclimate Modelling, Amiratu Yamusah
Predicting The Ancient Occurrence Of Evaporites Using Paleoclimate Modelling, Amiratu Yamusah
Earth & Environmental Sciences Theses - Archive
Evaporites are climatic indicators that depend on two main variables: mean annual temperature and mean annual precipitation. This study constructs a model that predicts the localities of ancient evaporites based on paleo- temperature and paleo- precipitation data. A climate envelope, a bivariate plot of temperature and precipitation, is constructed by intersecting the modern temperature and precipitation with climate data obtained from Fast Ocean Atmosphere Model (FOAM). Modern evaporites have a limited extent hence in this research, the yermosols- solonchak soil type was used as a proxy. The predictions were made for 16 time intervals. These were plotted on paleogeographic reconstructions …
Bismuth-Based Oxide Semiconductors: Mild Synthesis And Practical Applications, Hari Krishna Timmaji
Bismuth-Based Oxide Semiconductors: Mild Synthesis And Practical Applications, Hari Krishna Timmaji
Earth & Environmental Sciences Dissertations - Archive
In this dissertation study, bismuth based oxide semiconductors were prepared using 'mild' synthesis techniques - electrodepostion and solution combustion synthesis. Potential environmental remediation and solar energy applications of the prepared oxides were evaluated. Bismuth vanadate (BiVO₄) was prepared by electrodeposition and solution combustion synthesis. A two step electrosynthesis strategy was developed and demonstrated for the first time. In the first step, a Bi film was first electrodeposited on a Pt substrate from an acidic BiCl₃ medium. Then, this film was anodically stripped in a medium containing hydrolyzed vanadium precursor, to generate Bi3+, and subsequent BiVO₄ formation by in situ precipitation. …
Air Emissions From Natural Gas Exploration And Mining In The Barnett Shale Geologic Reservoir, Alisa Larraine Rich
Air Emissions From Natural Gas Exploration And Mining In The Barnett Shale Geologic Reservoir, Alisa Larraine Rich
Earth & Environmental Sciences Dissertations - Archive
This study evaluates air emissions from natural gas mining and production in the Barnett Shale within the Dallas/Fort Worth Metroplex. Due to advances in horizontal drilling and hydraulic fracturing, natural gas production in the Barnett Shale increased from 3 wells in 2000 to almost 8,000 wells in six Metroplex counties by 2008. Currently, information regarding emissions from natural gas production, particularly regarding hazardous air pollutants, is lacking; this information is particularly important given that drilling and production is occurring in highly urbanized areas. The objectives of this study were thus:* To identify the `fingerprint' of chemicals associated with natural gas …
Predicting The Geographic Distribution Of Ancient Soils With Special Reference To The Cretaceous, Arghya Goswami
Predicting The Geographic Distribution Of Ancient Soils With Special Reference To The Cretaceous, Arghya Goswami
Earth & Environmental Sciences Dissertations - Archive
Different kinds of soils form in different climatic regimes. Soils closely match climatic conditions. Therefore, they are one of the best indicators of past climates. This study uses the "climate envelope" technique developed by Moore (2007) to build a "paleo-soil prediction program". Though factors controlling soil formation are complex (Retallack, 1990), the best fit between a given soil type (Zobler 1999) and the annual range of rainfall and temperature (Legates and Wilmott 1990) are thought to be the primary factors. Each modern soil type has a unique climatic "fingerprint" or "climate envelope" defined by the range of rainfall and temperature …
Identifying Possible Hydrologic Recharge Zones In The Sangre De Cristo Aquifer On The Milliken Ranch In Las Vegas, Nm, Ian Hamilton
Identifying Possible Hydrologic Recharge Zones In The Sangre De Cristo Aquifer On The Milliken Ranch In Las Vegas, Nm, Ian Hamilton
Earth & Environmental Sciences Theses - Archive
Groundwater at the periphery of mountain ranges in the desert southwest has its provenance in two possible sources: local or regional flow. This study sought to identify the source of deep groundwater from wells on ranches in the Hogback area west of Las Vegas, NM, an area under scrutiny as a possible source for municipal use. Surface and groundwater samples were taken in the area and analyzed for water chemistry and stable isotope ratios of deuterium and oxygen-18. Ratio values were plotted against the Global Meteoric Water Line (GMWL) and also plotted on an interpolated map of precipitation values for …
The Impact Of Buffer Zone Changes On The Architecture Of The Paleozic Lower Cutler Beds Of Utah, Siavash Rastaghi
The Impact Of Buffer Zone Changes On The Architecture Of The Paleozic Lower Cutler Beds Of Utah, Siavash Rastaghi
Earth & Environmental Sciences Theses - Archive
The Shafer basin fluvial units, as being part of the Paradox fold and fault belt basin, received sediments from alluvial fans through mixed braided-meandering river systems that eroded the clastic rocks of the Uncompahgre highlands to the northeast and flowed southwestward through aeolian dune fields to an open sea during Pennsylvanian to early Permian time. The best exposed rocks of the Lower Cutler beds were photographed and investigated along the Colorado River in the Shafer and Canyonland basins. The Architectural Element Analysis technique was used to categorize bounding surface orders, and to identify lithofacies and fluvial elements such as lateral …
Climate Reconstruction Using Trace Element And Stable Isotope Signatures Preserved In An Early Late Pleistocene Stalagmite From Buckeye Creek Cave, Appalachian Mountains, Southern West Virginia, Usa, Ashley Rachelle Wright
Climate Reconstruction Using Trace Element And Stable Isotope Signatures Preserved In An Early Late Pleistocene Stalagmite From Buckeye Creek Cave, Appalachian Mountains, Southern West Virginia, Usa, Ashley Rachelle Wright
Earth & Environmental Sciences Theses - Archive
An early-Late Pleistocene stalagmite was recovered from Buckeye Creek Cave (37°58.57'N, 80°23.98'W), southeastern West Virginia, USA. The growth axis of stalagmite BCC-025 was sampled for δ18O, δ13C, and Sr/Ca of the calcite. A crude age model was developed using two Th-230 ages, from the top (~490 kyrBP) and bottom (~630 kyrBP) of the stalagmite. A more elaborate age model for stalagmite growth was developed using established marine isotope stage (MIS 13/14, 14/15, 15/16) boundaries. Overall, the MIS boundaries approximate the locations of major hiatuses along the axis of stalagmite growth. The proxy records developed from BCC-025 reveal less covariation and …
Chemostratigraphy And Paleoenvironment Of The Smithwick Formation, Fort Worth Basin, San Saba County, Texas, Elisha Nichole Hughes
Chemostratigraphy And Paleoenvironment Of The Smithwick Formation, Fort Worth Basin, San Saba County, Texas, Elisha Nichole Hughes
Earth & Environmental Sciences Theses - Archive
The Early Pennsylvanian-Age Smithwick Formation was deposited in the tectonically active Fort Worth Basin in North Central Texas during a time of well-documented global climatic instability during the Late Paleozoic ice age. Geochemical and stable isotopic results from two cores recovered from the southwestern portion of the FWB provide paleoenvironmental insight into the conditions under which the Smithwick was deposited. Specifically, major element geochemistry and mineralogical results suggest a depositional setting grading from a carbonate-rich facies (Marble Falls and Big Saline) into a transgressive siliciclastic-dominated mudrock (Smithwick) that coarsens upward into a progradational mudrock and silt/sand sequence (Atoka and Strawn). …
Chemostratigraphy And The Paleoceanography Of The Bossier-Haynesville Formation, East Texas Basin, Texas And La, Usa, Pukar Mainali
Chemostratigraphy And The Paleoceanography Of The Bossier-Haynesville Formation, East Texas Basin, Texas And La, Usa, Pukar Mainali
Earth & Environmental Sciences Theses - Archive
The fine-grained, dark, organic, calcareous Haynesville shale (Kimmeridgian), and the overlying carbonate-poor Bossier shale (Tithonian) was deposited during the warmer Jurassic period in the tectonically formed East Texas Basin. Thirteen drill cores recovered from six counties (Texas) and four parishes (Louisiana) have been studied for their geochemistry. Each core was analyzed at a 1-foot interval using a handheld x-ray fluorescence instrument, providing rapid, quantitative analysis of the following elemental concentrations: Mg, Al, S, Si, P, K, Ti, Ca, Mn, Fe, Mo, Cr, Ni, Cu, Zn, Th, Rb, U, Sr, Zr, and V. In addition, XRD analyses (10 samples from T.W. …
Morphology Of The Lower Missouri River: The Processes Involving Development Of Highly Sinuous Gooseneck Loop Cutoffs Exposed In The Surficial Deposits Of The River Floodplain, Daniel Earl Carlin
Morphology Of The Lower Missouri River: The Processes Involving Development Of Highly Sinuous Gooseneck Loop Cutoffs Exposed In The Surficial Deposits Of The River Floodplain, Daniel Earl Carlin
Earth & Environmental Sciences Theses - Archive
Mapping the surficial deposits of the Missouri River from Sioux City, Iowa to Mondamin, Iowa brought to light a prominent set of landforms exposed in the floodplain and which are also easily visible via aerial photography. The landforms are segments of highly sinuous channel fills that exhibit the characteristic of turning up-dip against the natural southern gradient of the river valley. These prominent channel scars, of which there are only five exposed in the study area, take on a recognizable “gooseneck” shape. The allostratigraphy for the reach of the Missouri River floodplain from Sioux City to Mondamin was mapped during …
Reducing Lead Bioavalability In Soil By Adding Apatite Ii, Dhary Saad Alkandary
Reducing Lead Bioavalability In Soil By Adding Apatite Ii, Dhary Saad Alkandary
Earth & Environmental Sciences Theses - Archive
This study was an examination of phosphate-induced immobilization of lead (Pb) in soils through addition of apatite II (fish bone material). The sources of Pb minerals in the soils examined in this in situ remediation study included anglesite (PbSO4), litharge (PbO), and cerrusite (PbCO3). Phosphate-induced Pb immobilization occurs when Pb ions are exchanged with calcium ions to form insoluble lead-phosphate (pyromorphite (Pb5(PO4)3Cl). Commercially available A- horizon soil was spiked with ten different Pb paints that contained different forms of Pb (e.g. PbO, PbCO3, PbSO4) and then sieved through a <250 micron mesh. Two and three replicates were prepared for each Pb paint sample type for apatite and no apatite additions, respectively. A series of large syringe tubes were filled separately with each of the spiked test soils to create a series of soil columns. In all, a set to sixty seven soil columns amended nominally with 5% w/w of apatite, and 2% Pb paint were tested. The change in potential bioavailability of lead in each soil column was evaluated after each column was eluted with Milli-Q water for one year. Soil samples were taken from each column at times zero, six, and twelve months. An in vitro bioaccessibility assessment of each soil column sample was accomplished using a simulated gastric fluid (SGF) digestion to determine the amount of Pb that could potentially be released into solution in the acid conditions in the human stomach. The assay involved using a SGF solution of 100 mL of Milli-Q water, 3 grams of glycine, and hydrochloric acid (HCl) in sufficient quantity to adjust the pH to a value 2.5. To this solution was added 0.5 gram or 1 gram of soil collected at each of the selected time points. Each SGF and soil suspension was tumbled for one hour at 37 °C in a modified Toxicity Characteristic Leaching Procedure (TCLP) system. A Scanning Electron Microscopy (SEM) spectrometer with a Back-Scattered Electron (BSE) detector and an Energy Dispersive X-ray Spectrometer (EDS) was used to obtain photomicrographs of soil samples and to determine the chemical nature of constituent Pb-bearing particles at time zero and at twelve months. A hand-held X-ray florescence (XRF) detector was used to determine the total Pb concentrations in soil samples at time zero. The study found that there was a general reduction in the amount of bioaccessible Pb in the soils at twelve months compared to time zero. This was supported by the identification of Pb-phosphate particle phases in the soils samples at twelve months. The effectiveness of using apatite II to remediate Pb-paint contaminated soil, through the immobilization of Pb through the formation of the sparingly soluble Pb-phosphate mineral pyromorphite (Pb5(PO4)3Cl) appears to be justified.
Chemostratigraphy Of The Eagle Ford Formation, Timothy J. Kearns
Chemostratigraphy Of The Eagle Ford Formation, Timothy J. Kearns
Earth & Environmental Sciences Theses - Archive
The Late Cretaceous Eagle Ford Formation contains the Cenomanian-Turonian Boundary (CTB). It crops out along the Red River and extends southward through the Dallas-Fort Worth Area of Texas, Waco, Austin and west towards Del Rio and Big Bend. The outcrops were not sampled. Sampling was conducted on cores located at the Bureau of Economic Geology (BEG). The cores were collected from Zavala, La Salle, Frio, Gonzalez, De Witt, and Bee Counties. The Austin Chalk Formation is located above the Eagle Ford Formation and the Buda Formation is located below it. Deposition of the Eagle Ford Formation occurred in the southern …
An Updated Gps Velocity Field For Puerto Rico And Virgin Islands: Constraints On Tectonic Setting And Internal Deformation, Desmond Kelvin Ihemedu
An Updated Gps Velocity Field For Puerto Rico And Virgin Islands: Constraints On Tectonic Setting And Internal Deformation, Desmond Kelvin Ihemedu
Earth & Environmental Sciences Theses - Archive
Puerto Rico and the northern Virgin Islands define the eastern end of the Greater Antilles, while the Puerto Rico trench and the Muertos Trough define the northern and the southern limits of the North American - Caribbean plate boundary zone. Three microplates have been defined: (1) Gonave, to the west; (2) Hispaniola, at the center; and (3) Puerto Rico and the northern Virgin Islands (PRVI) at the eastern end. Global Positioning System (GPS) geodesy was previously conducted in this region from 1994 to 2003. It was concluded that the locus of the highest permissible on-surface deformation in Puerto Rico and …