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Articles 151 - 180 of 441
Full-Text Articles in Geology
Comparison Of Beach Changes Induced By Two Hurricanes Along The Coast Of West-Central Florida, Ruoshu Zhao
Comparison Of Beach Changes Induced By Two Hurricanes Along The Coast Of West-Central Florida, Ruoshu Zhao
USF Tampa Graduate Theses and Dissertations
The beach profiles pre-and post-the Hurricane Hermine (2016) and Irma (2017) along the Sand Key barrier island were collected to quantify longshore variations in storm induced beach changes as well as to compare the beach changes caused by hydrodynamic conditions of the two different hurricanes.
Cross-shore beach profile are examined in 4 sections including dune field, dry beach, sand bar and whole beach to calculate beach change. The volume change for each section and shoreline contour change before and post the hurricane was computed. Hydrodynamic conditions were obtained from adjacent NOAA’s tide and wave gauges.
Both hurricanes generated high offshore …
New Insights On Secondary Minerals From Italian Sulfuric Acid Caves, Ilenia M. D'Angeli, Cristina Carbone, Maria Nagostinis, Mario Parise, Marco Vattano, Giuliana Madonia, Jo De Waele
New Insights On Secondary Minerals From Italian Sulfuric Acid Caves, Ilenia M. D'Angeli, Cristina Carbone, Maria Nagostinis, Mario Parise, Marco Vattano, Giuliana Madonia, Jo De Waele
International Journal of Speleology
Sulfuric acid minerals are important clues to identify the speleogenetic phases of hypogene caves. Italy hosts ~25% of the known worldwide sulfuric acid speleogenetic (SAS) systems, including the famous well-studied Frasassi, Monte Cucco, and Acquasanta Terme caves. Nevertheless, other underground environments have been analyzed, and interesting mineralogical assemblages were found associated with peculiar geomorphological features such as cupolas, replacement pockets, feeders, sulfuric notches, and sub-horizontal levels. In this paper, we focused on 15 cave systems located along the Apennine Chain, in Apulia, in Sicily, and in Sardinia, where copious SAS minerals were observed. Some of the studied systems (e.g., …
An Evaluation Of Marsh Shoreline Erosion And Sediment Deposition In The Grand Bay National Estuarine Research Reserve, Mississippi, Usa, Joseph Terrano
An Evaluation Of Marsh Shoreline Erosion And Sediment Deposition In The Grand Bay National Estuarine Research Reserve, Mississippi, Usa, Joseph Terrano
USF Tampa Graduate Theses and Dissertations
Coastal marshes serve important ecologic and economic functions, such as providing habitat, absorbing floodwaters and storm surges, and sequestering carbon. Throughout the northern Gulf of Mexico, coastal marshes are disappearing due to wave attack, sea-level rise, sediment export, and subsidence. Marsh area increases when sediments accumulate at the marsh shoreline, accrete vertically, and when non-marsh areas are colonized by marsh vegetation. Marsh shoreline erosion results in net marsh loss when transgression rates at the marsh-water edge exceed upland-marsh migration. The balance between marsh destroying and marsh creating processes determines the long-term survivability of a marsh system. Thus, processes of shoreline …
Environmental Controls On The Geochemistry Of Globorotalia Truncatulinoides In The Gulf Of Mexico: Implications For Paleoceanographic Reconstructions, Caitlin Elizabeth Reynolds
Environmental Controls On The Geochemistry Of Globorotalia Truncatulinoides In The Gulf Of Mexico: Implications For Paleoceanographic Reconstructions, Caitlin Elizabeth Reynolds
USF Tampa Graduate Theses and Dissertations
Modern observations of planktic foraminifera from sediment trap studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008–2014) in the northern Gulf of Mexico demonstrate that 92% of Globorotalia truncatulinoides flux occurs in winter (January, February, and March), and that encrusted and non-encrusted individuals represent calcification in distinct depth habitats. We use individual foraminiferal analysis (IFA) of G. truncatulinoides tests to investigate differences in the elemental (Mg/Ca) and isotopic composition (18O and 13C) of the encrusted and non-encrusted ontogenetic forms of G. truncatulinoides, and to estimate their calcification depth in …
Investigation Of Molluscan Survivorship Across The Cenomanian-Turonian Boundary Event Using Ecological Niche Modeling, Agathe E. Carrier
Investigation Of Molluscan Survivorship Across The Cenomanian-Turonian Boundary Event Using Ecological Niche Modeling, Agathe E. Carrier
Earth and Planetary Sciences ETDs
In the beginning of the Late Cretaceous, the Western Interior Seaway experienced the effects of a global ocean anoxic event (OAE2, or the Bonarelli Event) across the Cenomanian-Turonian (C/T) boundary (~94 Ma). This event resulted in major environmental and biological disturbances creating significant biotic turnover, with recent research suggesting near mass extinction levels in some clades. In this study we utilize a paleobiological application of a modern ecological modeling technique (PaleoENM), to test whether changes in species’ survivorship and distribution patterns across this event relate to changes in their predicted suitable habitat area and abiotic niche dimensions.
Results suggest that …
Extremely High Diversity Of Sulfate Minerals In Caves Of The Irazú Volcano (Costa Rica) Related To Crater Lake And Fumarolic Activity, Andrés Ulloa, Fernando Gázquez, Aurelio Sanz-Arranz, Jesús Medina, Fernando Rull, José María Calaforra, Guillermo E. Alvarado, María Martínez, Geoffroy Avard, J. Maarten De Moor, Jo De Waele
Extremely High Diversity Of Sulfate Minerals In Caves Of The Irazú Volcano (Costa Rica) Related To Crater Lake And Fumarolic Activity, Andrés Ulloa, Fernando Gázquez, Aurelio Sanz-Arranz, Jesús Medina, Fernando Rull, José María Calaforra, Guillermo E. Alvarado, María Martínez, Geoffroy Avard, J. Maarten De Moor, Jo De Waele
International Journal of Speleology
The caves of the Irazú volcano (Costa Rica), became accessible after the partial collapse of the NW sector of the Irazú volcano in 1994, offering the opportunity to investigate active minerogenetic processes in volcanic cave environments. We performed a detailed mineralogical and geochemical study of speleothems in the caves Cueva los Minerales and Cueva Los Mucolitos, both located in the northwest foothills of the main crater. Mineralogical analyses included X-ray diffraction (XRD) and Raman spectroscopy, while geochemical characterization used Energy Dispersive X-ray spectroscopy (EDX) coupled to Scanning Electron Microscopy (SEM). In addition, measurements of environmental parameters in the caves, …
Durmid Ladder Structure And Its Implications For The Nucleation Sites Of The Next M >7.5 Earthquake On The San Andreas Fault Or Brawley Seismic Zone In Southern California, Susanne U. Jänecke, Daniel K. Markowski, James P. Evans, Patricia Persaud, Miles Kenney
Durmid Ladder Structure And Its Implications For The Nucleation Sites Of The Next M >7.5 Earthquake On The San Andreas Fault Or Brawley Seismic Zone In Southern California, Susanne U. Jänecke, Daniel K. Markowski, James P. Evans, Patricia Persaud, Miles Kenney
Geosciences Faculty Publications
We integrated new geologic data with published geophysical data to document that the southernmost San Andreas fault zone, onshore of the Salton Sea, southern California, is a transpressional, 1–4-km-wide ladder-like structure. This newly identified Durmid ladder structure is a voluminous right-reverse fault zone that broadens across Durmid Hill around rotating domains of regularly spaced, left- and right- lateral cross faults. The active East Shoreline fault zone of the San Andreas fault forms the southwest margin of this fault zone, and it is generally parallel to the main strand of the San Andreas fault zone for >30 km, deforms Pliocene to …
Contribution Of Benthic Processes To The Growth Of Ooids On A Low-Energy Shore In Cat Island, The Bahamas, Giulio Mariotti, Sara B. Pruss, Roger E. Summons, Sharon A. Newman, Tanja Bosak
Contribution Of Benthic Processes To The Growth Of Ooids On A Low-Energy Shore In Cat Island, The Bahamas, Giulio Mariotti, Sara B. Pruss, Roger E. Summons, Sharon A. Newman, Tanja Bosak
Geosciences: Faculty Publications
Ooids are typically found in frequently reworked coastal sediments, and are thought to accrete by inorganic chemical precipitation around moving grains. The high organic content and the presence of biosignatures, however, suggest that ooids interact with benthic microbial communities. Here, we investigate the role of benthic processes on ooid growth on a leeward shore of Cat Island, The Bahamas. Polished ooids are present in the surf zone, whereas dull ooids and grapestones are present in microbially colonized sediments seaward of the surf zone. Wave hydrodynamics and sediment transport modeling suggest that microbially colonized sediments are mobilized at monthly time scales. …
Editorial For Special Issue “Geochemistry And Mineralogy Of Hydrothermal Metallic Mineral Deposits”, Theodore J. Bornhorst
Editorial For Special Issue “Geochemistry And Mineralogy Of Hydrothermal Metallic Mineral Deposits”, Theodore J. Bornhorst
Michigan Tech Publications, Part 1
The Special Issue of Minerals on Geochemistry and Mineralogy of Hydrothermal Metallic Mineral Deposits presents the results of diverse geochemical and mineralogical research from across the globe. It is aimed to demonstrate that geochemical and mineralogical variation, both within and among hydrothermal ore deposits can be applied to genetic models, to exploration and drilling programs, and more. The eight contributions reflect a wide range of deposits, as well as different types of geochemical and mineralogical research applied to them. While most of these studies are focused on gaining a better understanding of deposit genesis, the results have a far greater …
Spatial Trends And Variability Of Marsh Accretion Rates In Barataria Basin, Louisiana, Usa Using 210pb And 137cs Radiochemistry, Samuel Bryant Shrull
Spatial Trends And Variability Of Marsh Accretion Rates In Barataria Basin, Louisiana, Usa Using 210pb And 137cs Radiochemistry, Samuel Bryant Shrull
LSU Master's Theses
Coastal Louisiana is presently experiencing large amounts of coastal land loss with estimated rates exceeding 50 km2 lost per year. In an attempt to mitigate or reverse land loss, billions of dollars are earmarked for restoration projects that promote land reclamation, habitat stabilization, and defending against saline intrusion. This study was performed in an effort to better understand spatial trends of accretion rates in Barataria Basin in coastal Louisiana. Data for this project came from twenty-five shallow cores extracted over a broad span of the entire basin, from freshwater to saline environments. Cores were processed for 137Cs and …
A Sedimentological Record Of Early Miocene Ice Advance And Retreat, And-2a Drill Hole, Mcmurdo Sound, Antarctica, B. D. Field, G. H. Browne, Christopher R. Fielding, Fabio Florindo, David M. Harwood, Shelley Judge, Lawrence Krissek, Kurt S. Panter, Sandra Passchier, Stephen Pekar, Sonia Sandroni, Franco M. Talarico
A Sedimentological Record Of Early Miocene Ice Advance And Retreat, And-2a Drill Hole, Mcmurdo Sound, Antarctica, B. D. Field, G. H. Browne, Christopher R. Fielding, Fabio Florindo, David M. Harwood, Shelley Judge, Lawrence Krissek, Kurt S. Panter, Sandra Passchier, Stephen Pekar, Sonia Sandroni, Franco M. Talarico
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
The lowest 501 m (∼1139–638 m) of the AND-2A core from southern McMurdo Sound is the most detailed and complete record of early Miocene sediments in Antarctica and indicates substantial variability in Antarctic ice sheet activity during early Miocene time. There are two main pulses of diamictite accumulation recorded in the core, and three significant intervals with almost no coarse clasts. Each diamictite package comprises several sequences consistent with ice advance-retreat episodes.
The oldest phase of diamictite deposition, Composite Sequence 1 (CS1), has evidence for grounded ice at the drill site and has been dated around 20.2–20.1 Ma. It likely …
Spar Caves As Fossil Hydrothermal Systems: Timing And Origin Of Ore Deposits In The Delaware Basin And Guadalupe Mountains, New Mexico And Texas, Usa, David D. Decker, Victor J. Polyak, Yemane Asmerom
Spar Caves As Fossil Hydrothermal Systems: Timing And Origin Of Ore Deposits In The Delaware Basin And Guadalupe Mountains, New Mexico And Texas, Usa, David D. Decker, Victor J. Polyak, Yemane Asmerom
International Journal of Speleology
Studies of sulfuric acid hypogene speleogenesis have contributed significantly to understanding the history of the Guadalupe Mountains of southeast New Mexico and west Texas for at least the past 12 Ma. A recently published hypothesis of supercritical CO2 spar cave genesis provides information that constrains the timing of the start of uplift to between 27 and 16 Ma, and helps to explain landscape evolution of this region for the last 185 Ma. This new speleogenetic model is summarized here and shows that U-Pb dating of crystals from different spar caves reveal different ages, and that a majority of the …
Large Rotations Of Crustal Blocks In The Tjörnes Fracture Zone Of Northern Iceland, Andrew J. Horst, J. A. Carson, R. J. Varga
Large Rotations Of Crustal Blocks In The Tjörnes Fracture Zone Of Northern Iceland, Andrew J. Horst, J. A. Carson, R. J. Varga
Natural Resources and Earth Sciences Faculty Research
The interpretation of uppermost crustal deformation near oceanic transform faults is based on bathymetric lineaments and earthquake focal mechanisms, and relatively little is known about the detailed kinematics within the transform tectonized zone. The Tjörnes Fracture Zone is a broad zone of deformation produced by right‐lateral transform shearing in north Iceland and is partly exposed on land providing the opportunity to study shallow‐level crustal structure of mid‐Miocene, thick, oceanic‐like crust formed by subaerial spreading. A pronounced structural curvature of lava and dike orientations near the Húsavík‐Flatey Fault within the transform zone is well documented, yet of controversial origin. In order …
Nonbreeding Duck Use At Central Flyway National Wildlife Refuges, Kent Andersson, Craig A. Davis, Grant Harris, David A. Haukos
Nonbreeding Duck Use At Central Flyway National Wildlife Refuges, Kent Andersson, Craig A. Davis, Grant Harris, David A. Haukos
United States Geological Survey: Staff Publications
Within the U.S. portion of the Central Flyway, the U.S. Fish and Wildlife Service manages waterfowl on numerous individual units (i.e., Refuges) within the National Wildlife Refuge System. Presently, the extent of waterfowl use that Refuges receive and the contribution of Refuges to waterfowl populations (i.e., the proportion of the Central Flyway population registered at each Refuge) remain unassessed. Such an evaluation would help determine to what extent Refuges support waterfowl relative to stated targets, aid in identifying species requiring management attention, inform management targets, and improve fiscal efficiencies. Using historic monitoring data (1954–2008), we performed this assessment for 23 …
Application Of Handheld Ed-Xrf For High-Resolution Chemostratigraphy In Texturally Homogeneous Carbonate Mudstones: Salina A-1 Carbonate (Silurian), Michigan Basin, Matthew A. Hemenway
Application Of Handheld Ed-Xrf For High-Resolution Chemostratigraphy In Texturally Homogeneous Carbonate Mudstones: Salina A-1 Carbonate (Silurian), Michigan Basin, Matthew A. Hemenway
Masters Theses
Handheld energy dispersive x-ray fluorescence spectrometry (ED-XRF) is routinely used to observe elemental variability in fine-grained siliciclastics but has been applied rarely in fine-grained carbonates. Here, ED-XRF chemostratigraphy is utilized in the texturally homogenous, mudstones of the Silurian A-1 Carbonate (A-1C), Michigan Basin. Previous studies on the A-1C focused on the stratigraphic relationship with the underlying Niagaran reefs, so little is known about the geological variability in the basin center. In this study, high-resolution elemental data from nine cores were integrated with petrographic and mineralogical observations to evaluate two hypotheses: (1) Texturally homogeneous, basin-center mudstones in the A-1C have spatially …
Tectonic Controls On Alluvial Fan Dissection In The El Paso Mountains, Michael Thomas Gaffney
Tectonic Controls On Alluvial Fan Dissection In The El Paso Mountains, Michael Thomas Gaffney
Natural Resources Management and Environmental Sciences
The localized dissection of alluvial fans along the western El Paso Mountains is under question. A relatively minor, south dipping normal fault, previously unmentioned in scientific literature, cuts across Quaternary terraces and alluvial fans in the piedmont of the El Paso Mountains. The linear trend of footwall uplift and the pattern of stream incision into the footwall adjacent to the linear trend of footwall uplift reveal that fan dissection is a result of base level fall caused by ongoing tectonism along the El Paso fault system. The regional importance is discussed as the timing of faulting reveals relatively recent uplift …
Geomorphology Of The Potholes Of Rock Window Mesa, Chinle Valley, Az, Monte Fleming
Geomorphology Of The Potholes Of Rock Window Mesa, Chinle Valley, Az, Monte Fleming
Loma Linda University Electronic Theses, Dissertations & Projects
Potholes are depressions that have been carved out of bedrock. For this research project, we studied the 50 potholes on the top of Rock Window Mesa in Chinle Valley, AZ. Our first goal was to understand the processes currently affecting the addition or removal of pothole sediments. Our second goal was to understand pothole formation. While studying pothole sediment removal, we discovered that the wind speed threshold for deflation in the potholes is about 50 km/h, independent of pothole size. We conclude that deflation is the reason potholes don’t fill with sediment. In our study of pothole formation, we analyzed …
The Carnivores Of Agate Fossil Beds National Monument: Miocene Dens And Waterhole In The Valley Of A Dryland Paleoriver, Robert M. Hunt Jr., Robert Skolnick, Joshua Kaufman
The Carnivores Of Agate Fossil Beds National Monument: Miocene Dens And Waterhole In The Valley Of A Dryland Paleoriver, Robert M. Hunt Jr., Robert Skolnick, Joshua Kaufman
Zea E-Books Collection
In 1981 University of Nebraska paleontologists came upon an unexpected concentration of carnivore dens at Agate Fossil Beds National Monument in northwest Nebraska. The discovery of bones of Miocene beardogs, mustelids, and canids in their burrows was unparalleled and marked an exceptional event in the fossil record. Survey and excavation (1981–1990) established that six species of carnivores had, over time, occupied the dens with traces of their prey: juvenile and adult oreodonts, camels, and a neonatal rhinoceros. At least nine individuals of the wolf-like beardog Daphoenodon superbus, the most common carnivore, were identified from remains of young, mature, and aged …
Evaluation Of Potential Translocation Sites For An Imperiled Cyprinid, The Hornyhead Chub, Brian T. Hickerson, Annika W. Walters
Evaluation Of Potential Translocation Sites For An Imperiled Cyprinid, The Hornyhead Chub, Brian T. Hickerson, Annika W. Walters
United States Geological Survey: Staff Publications
Translocation of isolated species into suitable habitats may help to secure vulnerable, geographically limited species. Due to the decline of Wyoming Hornyhead Chub Nocomis biguttatus, conservation actions, such as the translocation of populations within the plausible historical range, are being considered to improve population redundancy and resiliency to disturbance events. Translocation of Wyoming Hornyhead Chub must be rigorously evaluated because a hatchery stock does not exist, so all fish used in translocations will come from the wild population. We present an approach to identify the best available translocation sites prior to translocation efforts taking place. We evaluated fish community composition …
Formation Of Evolved Rocks At Gale Crater By Crystal Fractionation And Implications For Mars Crustal Composition, Arya Udry, Esteban Gazel, Harry Y. Mcsween Jr.
Formation Of Evolved Rocks At Gale Crater By Crystal Fractionation And Implications For Mars Crustal Composition, Arya Udry, Esteban Gazel, Harry Y. Mcsween Jr.
Geoscience Faculty Research
The recent discovery of some ancient evolved rocks in Gale crater by the Curiosity rover has prompted the hypothesis that continental crust formed in early Martian history. Here we present petrological modeling that attempts to explain this lithological diversity by magma fractionation. Using the thermodynamical software MELTS, we model fractional crystallization of different Martian starting compositions that might generate felsic igneous compositions like those analyzed at Gale crater using different variables, such as pressure, oxygen fugacities, and water content. We show that similar chemical and mineralogical compositions observed in Gale crater felsic rocks can readily be obtained through different degrees …
A Novel Multiproxy Approach To Reconstructing Sea Surface Temperature In The Southwestern Gulf Of Mexico, Marissa Anne Vara
A Novel Multiproxy Approach To Reconstructing Sea Surface Temperature In The Southwestern Gulf Of Mexico, Marissa Anne Vara
LSU Master's Theses
Coral Sr/Ca is a widely-used proxy for sea surface temperature (SST); however, discrepancies in the coral Sr/Ca-SST relationship among colonies of the same species makes uncertainty in absolute temperature reconstructions larger than the climate signal yet climate variability studies are possible. Furthermore, the riverine input of terrestrial carbonate weathering products to the coastal waters can disrupt the coral Sr/Ca-SST signal by changing local seawater chemistry. This study evaluates the fidelity and reproducibly of coral SST proxies (Sr/Ca, Li/Ca, Mg/Li, Sr-U, Mg/Ca, and U/Ca) and a riverine-upwelling proxy (Ba/Ca) in four Orbicella faveolata colonies in two reefs offshore from Veracruz, Mexico …
Macrobenthic Infaunal Communities Associated With Deep‐Sea Hydrocarbon Seeps In The Northern Gulf Of Mexico, Travis W. Washburn, Amanda W. J. Demopoulos, Paul A. Montagna
Macrobenthic Infaunal Communities Associated With Deep‐Sea Hydrocarbon Seeps In The Northern Gulf Of Mexico, Travis W. Washburn, Amanda W. J. Demopoulos, Paul A. Montagna
United States Geological Survey: Staff Publications
There are thousands of seeps in the deep ocean worldwide; however, many questions remain about their contributions to global biodiversity and the surrounding deep‐sea environment. In addition to being globally distributed, seeps provide several benefits to humans such as unique habitats, organisms with novel genes, and carbon regulation. The purpose of this study is to determine whether there are unique seep macrobenthic assemblages, by comparing seep and nonseep environments, different seep habitats, and seeps at different depths and locations. Infaunal community composition, diversity, and abundance were examined between seep and nonseep background environments and among three seep habitats (i.e., microbial …
Introduction To A Resources Special Issue On Criticality Of The Rare Earth Elements: Current And Future Sources And Recycling, Simon M. Jowitt
Introduction To A Resources Special Issue On Criticality Of The Rare Earth Elements: Current And Future Sources And Recycling, Simon M. Jowitt
Geoscience Faculty Research
The rare earth elements (REE) are vital to modern technologies and society and are amongst the most important of the critical elements. This special issue of Resources examines a number of facets of these critical elements, current and future sources of the REE, the mineralogy of the REE, and the economics of the REE sector. These papers not only provide insights into a wide variety of aspects of the REE, but also highlight the number of different areas of research that need to be undertaken to ensure sustainable and secure supplies of these critical metals into the future.
Micropaleontological Record Of A Preserved, Late Pleistocene Bald Cypress Forest On The Northern Gulf Of Mexico Inner Shelf, Jonathan Thien Truong
Micropaleontological Record Of A Preserved, Late Pleistocene Bald Cypress Forest On The Northern Gulf Of Mexico Inner Shelf, Jonathan Thien Truong
LSU Master's Theses
A cluster of previously buried Taxodium distichum stumps are exposed and preserved in growth position at the bottom of a trough on the inner Gulf of Mexico (GOM) continental shelf in 18 m water depth and 13 km offshore Orange Beach, AL. Radiocarbon ages from wood and optically stimulated luminescence (OSL) dating of sediments suggest a Marine Isotope Stage (MIS) 3 age, or older. This study builds on the previous work of Gonzalez (2018) and Obeclz (2017). Five biofacies were identified in vibracore collected in 2015 and 2016: 1) the Holocene Mississippi-Alabama-Florida (MAFLA) sand sheet, 2) a Holocene interbedded sand …
Results Of Test-Hole Drilling For Observation Well Planning In The Lower Loup Natural Resources District, Spring 2017, Douglas R. Hallum P.G., Sue Olafsen Lackey, Steven S. Sibray
Results Of Test-Hole Drilling For Observation Well Planning In The Lower Loup Natural Resources District, Spring 2017, Douglas R. Hallum P.G., Sue Olafsen Lackey, Steven S. Sibray
Conservation and Survey Division: Faculty and Staff Publications
The High Plains Aquifer underlies much of Nebraska. It is the primary source of groundwater within the Lower Loup Natural Resources District (LLNRD) of central Nebraska. Water derived from the aquifer is an important natural resource for the area and supplies water for recreation, wildlife and agriculture, as well as domestic, municipal, and industrial uses. Falling spring water levels measured in existing observation and irrigation wells have raised concerns about possible changes in water availability, groundwater-surface water relationships and water quality in the area, prompting the LLNRD to propose test holes and the collection of additional groundwater data in the …
Organochlorine Chemical Residues In Northern Cardinal (Cardinalis Cardinalis) Eggs From Greater Washington, Dc Usa, Christopher J. Schmitt, Kathy E. Echols, Paul H. Peterman, Carl E. Orazio, K. Christiana Grim, Shirlee Tan, Nora E. Diggs, Peter P. Marra
Organochlorine Chemical Residues In Northern Cardinal (Cardinalis Cardinalis) Eggs From Greater Washington, Dc Usa, Christopher J. Schmitt, Kathy E. Echols, Paul H. Peterman, Carl E. Orazio, K. Christiana Grim, Shirlee Tan, Nora E. Diggs, Peter P. Marra
United States Geological Survey: Staff Publications
Northern Cardinal eggs from six neighborhoods near Washington DC were analyzed for organochlorine pesticides and PCBs. All compounds were detected more frequently and at higher concentrations in more heavily urbanized neighborhoods. DDT (mostly as p,pʹ-DDE) was detected in all neighborhoods. p,pʹ-DDT was typically 0.5‒16 ng/g (ww) in most suburban neighborhoods but was not detected (< 0.1 ng/g) in more rural areas; however, p,pʹ-DDT was 127‒1130 ng/g in eggs from two suburban Maryland nests and comprised 65.7% of total p,pʹ-DDT isomers in the most contaminated sample, indicating recent exposure to un-weathered DDT. Total chlordane (sum of 5 compounds) was 2‒70 ng/g; concentrations were greatest in older suburban neighborhoods. Total PCB (sum of detected congeners) was < 5‒21 ng/g. Congener patterns were similar in all neighborhoods and resembled those typical of weathered mixtures. Results indicate that wildlife remains exposed to low concentrations of legacy contaminants in suburban neighborhoods and that cardinal eggs can be used to monitor local- ized contamination.
Reconstruction Of Antarctic Cenozoic Paleoenvironments Through Palynological Analysis Of Subglacial Lake And Ice Stream Sediments, Patrick Baudoin
Reconstruction Of Antarctic Cenozoic Paleoenvironments Through Palynological Analysis Of Subglacial Lake And Ice Stream Sediments, Patrick Baudoin
LSU Master's Theses
The West Antarctic Ice Sheet (WAIS), with a large portion being grounded below sea level, is historically known for its instability. Timing and evaluating the magnitude of WAIS advance and retreat is essential to improve our understanding of control mechanisms. The scarcity of accessible subglacial geology in areas such as the Siple Coast in West Antarctica limits our understanding and ability to gauge WAIS response to environmental changes. To evaluate the ice-sheet history around the Siple Coast, i.e., when it was last covered by vegetation, access to sediment immediately below the ice-sheet is essential. In the absence of large-scale drilling, …
Provenance And Paleogeography Of The 25-17 Ma Rainbow Gardens Formation: Evidence For Tectonic Activity At Ca. 19 Ma And Internal Drainage Rather Than Throughgoing Paleorivers On The Southwestern Colorado Plateau, Melissa A. Lamb, L. Sue Beard, Malia Dragos, Andrew D. Hanson, Thomas A. Hickson, Mark Sitton, Paul J. Umhoefer, Karl E. Karlstrom, Nelia Dunbar, William Mcintosh
Provenance And Paleogeography Of The 25-17 Ma Rainbow Gardens Formation: Evidence For Tectonic Activity At Ca. 19 Ma And Internal Drainage Rather Than Throughgoing Paleorivers On The Southwestern Colorado Plateau, Melissa A. Lamb, L. Sue Beard, Malia Dragos, Andrew D. Hanson, Thomas A. Hickson, Mark Sitton, Paul J. Umhoefer, Karl E. Karlstrom, Nelia Dunbar, William Mcintosh
Geoscience Faculty Research
The paleogeographic evolution of the Lake Mead region of southern Nevada and northwest Arizona is crucial to understanding the geologic history of the U.S. Southwest, including the evolution of the Colorado Plateau and formation of the Grand Canyon. The ca. 25–17 Ma Rainbow Gardens Formation in the Lake Mead region, the informally named, roughly coeval Jean Conglomerate, and the ca. 24–19 Ma Buck and Doe Conglomerate southeast of Lake Mead hold the only stratigraphic evidence for the Cenozoic pre-extensional geology and paleogeography of this area. Building on prior work, we present new sedimentologic and stratigraphic data, including sandstone provenance and …
Miocene-Quaternary Deformation Along The Central Maynard Lake Fault, Pahranagat Shear Zone, Nevada, Alexander Peck
Miocene-Quaternary Deformation Along The Central Maynard Lake Fault, Pahranagat Shear Zone, Nevada, Alexander Peck
UNLV Theses, Dissertations, Professional Papers, and Capstones
The left-lateral Pahranagat shear zone (PSZ) and Caliente-Enterprise zone (CEZ) exist at the boundary between two sub-provinces, the Northern (NBR) and Central Basin and Range (CBR). The PSZ contains three major ENE striking sinistral faults, including the Maynard Lake fault (MLF), which is the longest fault and marks the southern boundary of the zone. The PSZ has been suggested to be a transfer zone, but little is known about the structures along these major faults that are involved in strain transfer. These left-lateral systems exist within the Central Nevada seismic belt which has experienced significant earthquakes in recent history. Possible …
Holocene Climate Evolution Of Continental Western Eurasia Constrained By Stable-Isotope And Cation Geochemistry Of U-Th-Dated Speleothems And Meteogenic Travertine, Jonathan Lloyd Baker
Holocene Climate Evolution Of Continental Western Eurasia Constrained By Stable-Isotope And Cation Geochemistry Of U-Th-Dated Speleothems And Meteogenic Travertine, Jonathan Lloyd Baker
UNLV Theses, Dissertations, Professional Papers, and Capstones
Reliable reconstructions of global and regional climate during the Holocene (11,700 years ago to present) are vital to constraining the natural range of climate variability and testing state-of-the-art models, which seek to forecast the near- and long-term impact of anthropogenic greenhouse forcing. Much of continental Eurasia is still underrepresented, however, in geological proxy reconstructions of Holocene climate variability, and the vast majority of paleoclimate data only reflect conditions during peak summer months (JJA) or the growing season. The paucity of winter proxy data has therefore been cited as a possible explanation for the current mismatch between geological proxy-based and climate-model …