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Articles 21331 - 21360 of 29947
Full-Text Articles in Geology
Late Jurassic Dinosaurs On The Move, Gastroliths And Long-Distance Migration, Josh Malone
Late Jurassic Dinosaurs On The Move, Gastroliths And Long-Distance Migration, Josh Malone
Geography: Student Scholarship & Creative Works
The Jurassic Morrison Formation of the Rocky Mountain and Colorado Plateau regions is famous for its dinosaur fossils. The Morrison Formation (150-157 Ma) is comprised mostly of sandstone and mudstone that was deposited in a terrestrial deposition system that included fluvial, paludal, and lacustrine environments. Paleocurrent data indicates that Morrison sediment was transported to the north and east. Within the Morrison Formation, we find exotic pebble and cobble-size durable clasts of quartzite, chert and vein quartz weathering out of the mudstone paleosols. We interpret these exotic clasts as gastroliths, carried within the gastric mills of dinosaurs. For this study, we …
Improving Aquifer Characterization Through Integration Of Airborne Electromagnetics (Aem) And Well Hydrographs, Jacqueline Polashek
Improving Aquifer Characterization Through Integration Of Airborne Electromagnetics (Aem) And Well Hydrographs, Jacqueline Polashek
School of Natural Resources: Dissertations, Theses, and Student Research
The objective of this study is to evaluate methods of hydrostratigraphic modeling using geophysics and well hydrographs at the eastern edge of the High Plains aquifer (HPA) in Platte and Colfax counties within Nebraska, USA. The HPA is very heterogeneous in the study area, being hosted by architecturally complex glacial sediments and having many irregular hydraulic boundaries. Further, the HPA exhibits local variations between unconfined and confined conditions. Pumping in such bounded aquifers can be unsustainable because of cost increases and lost agricultural productivity. Moreover, the large drawdowns typical of confined aquifers can contribute to well interference during heavy pumping. …
Crustal Structure Beneath The East Coast Magnetic Anomaly From Seismic Refraction Tomography, Collin C. Brandl
Crustal Structure Beneath The East Coast Magnetic Anomaly From Seismic Refraction Tomography, Collin C. Brandl
Earth and Planetary Sciences ETDs
Syn-rift igneous addition is necessary for successful continental breakup. Past investigations of passive margins have focused on strike perpendicular structure, but potential field anomalies indicate that significant crustal variations may be present. Data from 21 ocean bottom seismometers was acquired as part of the Eastern North American Margin Community Seismic Experiment and was used for tomographic inversion to create 2D velocity models of the margin that are representative of crustal structure. Crustal thickness varies along-strike from ~20 km to ~24 km and a high velocity (Vp > 7 km/s) layer is present at the base of the crust above the Moho. …
Why Gamma Distribution Of Seismic Inter-Event Times: A Theoretical Explanation, Laxman Bokati, Aaron A. Velasco, Vladik Kreinovich
Why Gamma Distribution Of Seismic Inter-Event Times: A Theoretical Explanation, Laxman Bokati, Aaron A. Velasco, Vladik Kreinovich
Departmental Technical Reports (CS)
It is known that the distribution of seismic inter-event times is well described by the Gamma distribution. Recently, this fact has been used to successfully predict major seismic events. In this paper, we explain that the Gamma distribution of seismic inter-event times can be naturally derived from the first principles.
Increased Fluvial Runoff Terminated Inorganic Aragonite Precipitation On The Northwest Shelf Of Australia During The Early Holocene, Maximilian Hallenberger, Lars Reuning, Stephen J. Gallagher, Stefan Back, Takeshige Ishiwa, Beth A. Christensen, Kara Bogus
Increased Fluvial Runoff Terminated Inorganic Aragonite Precipitation On The Northwest Shelf Of Australia During The Early Holocene, Maximilian Hallenberger, Lars Reuning, Stephen J. Gallagher, Stefan Back, Takeshige Ishiwa, Beth A. Christensen, Kara Bogus
School of Earth & Environment Departmental Research
Inorganic precipitation of aragonite is a common process within tropical carbonate environments. Across the Northwest Shelf of Australia (NWS) such precipitates were abundant in the late Pleistocene, whereas present-day sedimentation is dominated by calcitic bioclasts. This study presents sedimentological and geochemical analyses of core data retrieved from the upper 13 meters of IODP Site U1461 that provide a high-resolution sedimentary record of the last ~15 thousand years. Sediments that formed from 15 to 10.1 ka BP are aragonitic and characterised by small needles (<5 >µm) and ooids. XRF elemental proxy data indicate that these sediments developed under arid conditions in …5>
Groundwater Investigations To Support Irrigated Agriculture At La Grange, Western Australia: 2013–18 Results, Robert J. Paul, Gregory Paul Raper, Richard J. George Dr, Nicholas J. Wright, Adam M. Lillicrap, Peter S. Gardiner
Groundwater Investigations To Support Irrigated Agriculture At La Grange, Western Australia: 2013–18 Results, Robert J. Paul, Gregory Paul Raper, Richard J. George Dr, Nicholas J. Wright, Adam M. Lillicrap, Peter S. Gardiner
Resource management technical reports
The Broome Sandstone aquifer is the main aquifer and groundwater resource in the La Grange area, near Broome in the West Kimberley, Western Australia. Land use is dominated by cattle grazing on pastoral stations, dispersed mining and tourism. Irrigated agriculture has developed at a small scale, with about 470 hectares under cultivation in 2014. Groundwater abstraction is licensed under the La Grange groundwater allocation plan (Department of Water 2010) and managed by the Department of Water and Environmental Regulation. The La Grange groundwater allocation area is split into the La Grange North subarea and La Grange South subarea, with groundwater …
2d Electrical Resistivity And Hydrological Study Of A Solute Plume’S Migration Pathway Through Sandy Loam Within Nacogdoches County, Texas, Usa, Tyler Tandy, Wesley Brown, Kevin Stafford
2d Electrical Resistivity And Hydrological Study Of A Solute Plume’S Migration Pathway Through Sandy Loam Within Nacogdoches County, Texas, Usa, Tyler Tandy, Wesley Brown, Kevin Stafford
Electronic Theses and Dissertations
combined geophysical and hydrological study was conducted in a sandy loam near the campus of Stephen F. Austin State University in Nacogdoches, Texas. The study area contained three preinstalled piezometers which are located in the Sparta Sand of the Eocene Claiborne Group, a regressive tract of the Eocene sea. Electrical DC resistivity surveys were conducted across one fifty-six-meter-long traverse using AGI’s multi-electrode SuperSting R8 WIFI RES/IP/SP system, which allowed for rapid and reliable data collection. The resistivity line was surveyed using the dipole-dipole array configuration, which has been proven to produce high-quality horizontal resolution. Over the duration of fourteen days, …
Assessing The Impact Of 3d Printed Terrain On Teaching Topography In Introductory Earth Science Labs, Jay Alan Cockrell
Assessing The Impact Of 3d Printed Terrain On Teaching Topography In Introductory Earth Science Labs, Jay Alan Cockrell
Masters Theses
Learning to effectively read topographic maps is challenging for students, as these maps contain 3D representations of terrain displayed on a 2D surface map. This project assessed student learning when 3D terrain printed from a portion of the laboratory quadrangle map currently in use was introduced into an earth science course for non-science majors. Using a quasi-experimental design with nonequivalent groups across two semesters, performance on the Modified Topographic Map Assessment (MTMA) administered as a pre- and posttest was used to compare learning outcomes between the traditional lab and the 3D print lab intervention. Students in the traditional (n = …
Evaluating The Effects Of Sodium, Potassium, Magnesium, And Calcium Concentrations On Dolomite Stoichiometry, Cation Ordering, And Reaction Rate, Hanna F. Cohen
Evaluating The Effects Of Sodium, Potassium, Magnesium, And Calcium Concentrations On Dolomite Stoichiometry, Cation Ordering, And Reaction Rate, Hanna F. Cohen
Masters Theses
Numerous environmental factors affect dolomitization. Shallow peritidal and restricted marine environments, for example, are often associated with more abundant and more stoichiometric dolomite than deeper marine environments. Higher fluid Mg/Ca ratios resulting from gypsum precipitation are often invoked to explain this observation, even when evidence of evaporites is absent. In this study, high-temperature dolomitization experiments show that the concentrations of major cation concentrations (Na, K, Mg, and Ca) impact dolomite stoichiometry and reaction rate. Nearly 200 batch dolomitization experiments were run whereby 100 mg of natural aragonite ooids were dolomitized at 215°C in ionic solutions. Fluid [NaCl] and [KCl] correlate …
Suitability Assessment For Integrated Urban Development In Makkah City Of Saudi Arabia, Mislat Alotaibi
Suitability Assessment For Integrated Urban Development In Makkah City Of Saudi Arabia, Mislat Alotaibi
Graduate Theses and Dissertations
Makkah – the third most populated city in Saudi Arabia with a population of 1,684,408 according to the 2010 demographic survey conducted by the Saudi General Authority for Statistics – is experiencing urban sprawl, which can be defined as an unplanned urban expansion that might degrade the environment and diminish the aesthetic view. This is a persisting problem in Makkah driven by multitude of processes involving the random expansion in its undeveloped land and the removal of its historic mountains surrounding Al-Masjid Al-Haram (the Holy Mosque) in an attempt to push the city limit of urban capacity within its administrative …
Evidence Of Limited Recruitment Of Pallid Sturgeon In The Lower Missouri River, Kirk D. Steffensen, Kimberly Chojnacki, Jeffrey A. Kalie, Meredith L. Bartron, Edward J. Heist, Kyle R. Winders, Nathan C. Loecker, Wyatt J. Doyle, Timothy L. Welker
Evidence Of Limited Recruitment Of Pallid Sturgeon In The Lower Missouri River, Kirk D. Steffensen, Kimberly Chojnacki, Jeffrey A. Kalie, Meredith L. Bartron, Edward J. Heist, Kyle R. Winders, Nathan C. Loecker, Wyatt J. Doyle, Timothy L. Welker
United States Geological Survey: Staff Publications
Pallid Sturgeon Scaphirhynchus albus are endemic to the Missouri and Mississippi river basins and are rare throughout their range. The species was listed as federally endangered with little to no evidence of natural recruitment. Since population augmentation was initiated as a recovery objective in the early 1990s, thousands of hatchery-origin Pallid Sturgeon have been stocked in the lower Missouri River (Gavins Point Dam [river kilometer 1,305.1] to the confluence of the Mississippi River [river kilometer 0.0]). Efforts to discriminate natural reproduction and recruitment of wild-origin Pallid Sturgeon from hatchery-origin fish has been hampered by tag loss in hatchery-origin sturgeon, inconsistent …
Paleoseismology Of The Central Garlock Fault In Searles Valley, California, Kyle Pena
Paleoseismology Of The Central Garlock Fault In Searles Valley, California, Kyle Pena
Electronic Theses, Projects, and Dissertations
In this study, a paleoseismic trench with limited age constraints that was previously excavated in 1990 across the central Garlock Fault near Christmas Canyon, in Searles Valley, California, was reopened to take advantage of new advances in luminescence dating techniques to investigate potential temporal variability in earthquake recurrence on the Garlock fault and to analyze previously unexposed older earthquake evidence. The trench exposed interbedded alluvial sand and pebble-gravels, with well-sorted, rounded, lacustrine sand from the most recent highstand of pluvial Lake Searles present at the base of the trench. Preliminary findings suggest at least 10 surface rupturing earthquake events occurred …
A Granger Causality Analysis Of Groundwater Patterns Over A Half-Century, Nitin K. Singh, David M. Borrok
A Granger Causality Analysis Of Groundwater Patterns Over A Half-Century, Nitin K. Singh, David M. Borrok
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Groundwater depletion in many areas of the world has been broadly attributed to irrigation. However, more formal, data-driven, causal mechanisms of long-term groundwater patterns have not been assessed. Here, we conducted the first Granger causality analysis to identify the "causes" of groundwater patterns using the rice-producing parishes of Louisiana, USA, as an example. Trend analysis showed a decline of up to 6 m in groundwater level over 51 years. We found that no single cause explained groundwater patterns for all parishes. Causal linkages were noted between groundwater and area harvested, number of irrigation wells, summer precipitation totals, and drought. Bi-directional …
Manus Descriptions Of An Undescribed Mastodon From The Latest Miocene-Earliest Pliocene Gray Fossil Site, With Comparisons To Other North American Proboscidean Taxa, Brenna Hart-Farrar
Manus Descriptions Of An Undescribed Mastodon From The Latest Miocene-Earliest Pliocene Gray Fossil Site, With Comparisons To Other North American Proboscidean Taxa, Brenna Hart-Farrar
Electronic Theses and Dissertations
A detailed morphological description of a proboscidean manus from the Gray Fossil Site (GFS), Gray, Tennessee is provided. Manus elements from an American mastodon (Mammut americanum), a Britt’s shovel-tusker (Amebelodon britti), an undescribed small gomphothere species, and a Columbian mammoth (Mammuthus columbi) are used for comparisons. Linear measurements indicate proportional differences between the GFS mastodon and other proboscidean taxa ranging from the Hemphillian to Rancholabrean land mammal ages. Possible pathologies are also described. The purpose of this study is to determine how the GFS mastodon differs in manus morphology and locomotion from different proboscidean …
Fracture Analysis Of The Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge, Trent Jackson
Fracture Analysis Of The Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge, Trent Jackson
Master's Theses
Atlantis Bank (AB) is an oceanic core complex (OCC), formed at the slow-spreading (spreading rate/yr) Southwest Indian Ridge (SWIR)-Atlantis II transform junction. AB is a domal massif composed of lower crustal and upper mantle rocks exhumed along a normal-sense detachment shear zone/fault. OCCs are of high interest since oceanic crust comprises the majority of Earth’s crust and OCCs form up to 15% of the crust that is formed at slow-spreading ridges. Brittle deformation, such as faults and fractures provide pathways for fluids to interact with the crust, which increases heat and mass exchange between the crust and hydrosphere, and is …
Evolution Of The Book Cliffs Dryland Escarpment In Central Utah - Establishing Rates And Testing Models Of Escarpment Retreat, Nicholas R. Mccarroll
Evolution Of The Book Cliffs Dryland Escarpment In Central Utah - Establishing Rates And Testing Models Of Escarpment Retreat, Nicholas R. Mccarroll
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Since the earliest explorations of the Colorado Plateau, geologists have suspected that cliffs are retreating back laterally. Clarence Dutton envisioned “the beds thus dissolving edge wise until after the lapse of millions of centuries their terminal cliffs stand a hundred miles or more back from their original position” when he wrote about the landscape in 1882. While many geologic studies have determined how fast rivers cut down through the Plateau, only a few studies have calculated how quickly cliffs retreat laterally, and geologists have been arguing since the 1940’s what exactly drives cliffs to retreat in the first place. We …
Characterizing Hydrothermal System Groundwater Dynamics Using Conservative And Non-Conservative Tracers: Insights And Implications Drawn From Study At The Taupo Volcanic Zone (New Zealand) And Valles Caldera (Usa), Joshua Michael Blackstock
Characterizing Hydrothermal System Groundwater Dynamics Using Conservative And Non-Conservative Tracers: Insights And Implications Drawn From Study At The Taupo Volcanic Zone (New Zealand) And Valles Caldera (Usa), Joshua Michael Blackstock
Graduate Theses and Dissertations
Hydrothermal systems constitute an important component of heat and mass transport within Earth’s crust having direct and indirect impacts to society. Investigating contemporary hydrochemical differences and change are critical to evaluating and deconvolving factors that influence geothermal systems through time. In this dissertation, groundwater mixing approaches were used to study hydrochemical differences in two globally significant hydrothermal areas, which included fabrication of a low-cost dissolved CO2 monitoring for dissolved inorganic carbon (DIC). In the Taupo Volcanic Zone (New Zealand), empirical spatial relations were used to derive low-temperature groundwater end-members of Cl and Cl/Br for end-member mixing analysis (EMMA). Using EMMA, …
An Investigation Of Metal Sulfides As The Source Of The Low Emissivity Anomaly On The Highlands Of Venus, Sara Taeko Port
An Investigation Of Metal Sulfides As The Source Of The Low Emissivity Anomaly On The Highlands Of Venus, Sara Taeko Port
Graduate Theses and Dissertations
Since its detection in the 1960s the source of the unusual radar emissivity signal seen on several highlands on Venus has long eluded researchers. Researchers have determined that a mineral with a high dielectric constant could explain the signal. Using a Venus simulation chamber, we experimentally investigated this enigma to build upon the candidate mineral list that has been compiled over the last several decades. We tested the stability of 8 different minerals and elements at two to three different temperature/pressure regimes in three different gas mixtures meant to simulate the conditions found on Venus for a period of no …
The Shelf To Basin Transition And Tectonostratigraphy Of The Atoka Formation (Lower Pennsylvanian) In The Arkoma Basin, Northwest Arkansas, Travis Gibson White
The Shelf To Basin Transition And Tectonostratigraphy Of The Atoka Formation (Lower Pennsylvanian) In The Arkoma Basin, Northwest Arkansas, Travis Gibson White
Graduate Theses and Dissertations
The east-to-west oriented Arkoma Basin is a peripheral foreland basin or depositional trough that developed during the Carboniferous Period. This formation covers an aerial extent of approximately 33,800 square miles and spans from west-central Arkansas into southeastern Oklahoma (McGilvery, Manger, and Zachry, 2016; Perry, 1995). The Atoka Formation, deposited during the early Pennsylvanian, is the largest Paleozoic formation by aerial extent in the state of Arkansas and is located within and comprises the bulk of Arkoma Basin sediments (McFarland, 2004; Nance, 2018). This formation has been informally divided into three divisions, the lower, middle, and upper, based on their stratigraphic …
Evidence Of Variable Climate And Resources During The Late Pleistocene And Holocene At Gona, Ethiopia, Marie White
Evidence Of Variable Climate And Resources During The Late Pleistocene And Holocene At Gona, Ethiopia, Marie White
Steeplechase: An ORCA Student Journal
The African Humid Period (AHP) spanned a period of approximately 15 to 5 thousand years ago (ka) and resulted in Northern and Eastern Africa being wetter than today. This climate change event impacted flora, fauna, and humans to an unknown extent. Much of the work on the AHP across Eastern Africa utilizes lacustrine and marine proxies rather than river-based (fluvial). Gona, located in the Afar region of Ethiopia, is known for its extensive archaeological and fossil records in fluvial deposits. However, the paleoenvironment of the AHP at Gona has not been investigated. This study uses stratigraphy, geochronology, and paleopedology to …
Crustal Density Variation Of The Eastern U.S., Henglei Zhang, Dhananjay Ravat, Anthony R. Lowry
Crustal Density Variation Of The Eastern U.S., Henglei Zhang, Dhananjay Ravat, Anthony R. Lowry
Earth and Environmental Sciences Research Data
EarthScope’s USArray Transportable Array (TA) has shortcomings for the purpose of interpreting geologic features of wavelengths less than the 70 km TA station spacing, but these can be overcome by using higher spatial resolution gravity data. In this study, we exploit USArray receiver functions to reduce non-uniqueness in the interpretation of gravity anomalies. We model gravity anomalies from previously-derived density variations of sedimentary basins, crustal Vp/Vs variation, Moho variation, and upper mantle density variation derived from body-wave imaging informed by surface wave tomography to estimate Vp/Vs. Although average densities and density contrasts for these seismic variations can be derived, …
Sampling Methods For Luminescence Dating Of Subsurface Deposits From Cores, Michelle Nelson, Tammy M. Rittenour, Harriet Cornachione
Sampling Methods For Luminescence Dating Of Subsurface Deposits From Cores, Michelle Nelson, Tammy M. Rittenour, Harriet Cornachione
Geosciences Faculty Publications
Study of subsurface deposits often requires coring or drilling to obtain samples for sedimentologic and geochemical analysis. Geochronology is a critical piece of information for stratigraphic correlation and rate calculations. Increasingly, luminescence dating is applied to sediment cores to obtain depositional ages. This paper provides examples and discussion of guidelines for sampling sediment core for luminescence dating. Preferred protocols are dependent on the extraction method, sedimentology, core integrity, and storage conditions. The methods discussed include subsampling of sediment in opaque core-liners, cores without liners, previously open (split) cores, bucket auger samples, and cuttings, under red lighting conditions. Two important factors …
Postmagmatic Tectonic Evolution Of The Outer Izu‐Bonin Forearc Revealed By Sediment Basin Structure And Vein Microstructure Analysis: Implications For A 15 Ma Hiatus Between Pacific Plate Subduction Initiation And Forearc Extension, Walter Kurz, Peter Micheuz, Gail L. Christeson, M. Reagan, John W. Shervais, Steffen Kutterolf, A. Robertson, Kurt Krenn, K. Michibayashi, D. Quandt
Postmagmatic Tectonic Evolution Of The Outer Izu‐Bonin Forearc Revealed By Sediment Basin Structure And Vein Microstructure Analysis: Implications For A 15 Ma Hiatus Between Pacific Plate Subduction Initiation And Forearc Extension, Walter Kurz, Peter Micheuz, Gail L. Christeson, M. Reagan, John W. Shervais, Steffen Kutterolf, A. Robertson, Kurt Krenn, K. Michibayashi, D. Quandt
Geosciences Faculty Publications
International Ocean Discovery Program Expedition 352 recovered sedimentary‐volcaniclastic successions and extensional structures (faults and extensional veins) that allow the reconstruction of the Izu‐Bonin forearc tectonic evolution using a combination of shipboard core data, seismic reflection images, and calcite vein microstructure analysis. The oldest recorded biostratigraphic ages within fault‐bounded sedimentary basins (Late Eocene to Early Oligocene) imply a ~15 Ma hiatus between the formation of the igneous basement (52 to 50 Ma) and the onset of sedimentation. At the upslope sites (U1439 and U1442) extension led to the formation of asymmetric basins reflecting regional stretch of ~16–19% at strain rates of …
The Peculiar Nature Of Florida’S Sandhill Wetlands, Ponds & Lakes— Their Ecohydrology, Relationship With The Regional Aquifer & Importance Within The Landscape., Renae Starr Nowicki
The Peculiar Nature Of Florida’S Sandhill Wetlands, Ponds & Lakes— Their Ecohydrology, Relationship With The Regional Aquifer & Importance Within The Landscape., Renae Starr Nowicki
USF Tampa Graduate Theses and Dissertations
This dissertation explores the ecohydrology of Florida’s peculiar and poorly studied sandhill wetland and water features, particularly those located in west-central Florida. The primary research goals include: compilation and summarization of the available ecohydrologic information for features across Florida; comparison of water level and water geochemistry data between sandhill wetlands and waters and the regional aquifer to provide evidence of regional hydrologic control; and use of geophysical applications to examine the hydraulic connections between sandhill wetlands and waters and the regional aquifer.
From this research, a natural history of sandhill wetland and water ecohydrology is presented, highlighting: the differences between …
Mapping Crustal Shear Wave Velocity Structure And Radial Anisotropy Beneath West Antarctica Using Seismic Ambient Noise, J. P. O'Donnell, Audrey D. Huerta, J. Paul Winberry
Mapping Crustal Shear Wave Velocity Structure And Radial Anisotropy Beneath West Antarctica Using Seismic Ambient Noise, J. P. O'Donnell, Audrey D. Huerta, J. Paul Winberry
All Faculty Scholarship for the College of the Sciences
Using 8- to 25-s-period Rayleigh and Love wave phase velocity dispersion data extracted from seismic ambient noise, we (i) model the 3-D shear wave velocity structure of the West Antarctic crust and (ii) map variations in crustal radial anisotropy. Enhanced regional resolution is offered by the UK Antarctic Seismic Network. In the West Antarctic Rift System (WARS), a ridge of crust ∼26–30km thick extending south from Marie Byrd Land separates domains of more extended crust (∼22km thick) in the Ross and Amundsen Sea Embayments, suggesting along-strike variability in the Cenozoic evolution of the WARS. The southern margin of the WARS …
Seismic Evidence For Significant Melt Beneath The Long Valley Caldera, California, Usa, Ashton F. Flinders, David R. Shelly, Philip B. Dawson, David P. Hill, Barbara Tripoli, Yang Shen
Seismic Evidence For Significant Melt Beneath The Long Valley Caldera, California, Usa, Ashton F. Flinders, David R. Shelly, Philip B. Dawson, David P. Hill, Barbara Tripoli, Yang Shen
United States Geological Survey: Staff Publications
A little more than 760 ka ago, a supervolcano on the eastern edge of California (United States) underwent one of North America’s largest Quaternary explosive eruptions. Over this ~6-day-long eruption, pyroclastic flows blanketed the surrounding ~50 km with more than 1400 km3 of the now-iconic Bishop Tuff, with ashfall reaching as far east as Nebraska. Collapse of the volcano’s magma reservoir created the restless Long Valley Caldera. Although no rhyolitic eruptions have occurred in 100 k.y., beginning in 1978, ongoing uplift suggests new magma may have intruded into the reservoir. Alternatively, the reservoir could be approaching final crystallization, with present-day …
Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero
Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero
LSU Master's Theses
A provenance study of quartz arenites that stratigraphically are closely associated with major Ordovician K-bentonites has been conducted in order to further our understanding of the tectonic setting of eastern Laurentia during the Late Ordovician. Using laser ablation ICP-MS, detrital zircons separated from Ordovician sandstone samples in the southeastern Appalachian Mountains (Virginia to Alabama) were dated using U-Pb geochronology. Analytical results show three dominate age ranges for the zircons from these sandstones: ~440-490 Ma, ~900-1300 Ma, and ~1300-1500 Ma. In addition, some zircon ages grouped into older ranges of ~1600-1800 Ma, ~1800-1900 Ma, and ~2600-2800 Ma. Zircon ages from ~900-2800 …
Sandy Dredge Pit Sedimentation – Characteristics And Processes In Caminada Borrow Area, Ship Shoal, Louisiana Shelf, Usa, Zehao Xue
LSU Master's Theses
Mississippi River Deltaic Plain’s barrier islands are undergoing rapid disintegration due to high rates of subsidence and a deficit in coastal sediment supply. To mitigate for barrier island land loss, Louisiana has implemented a restoration program that supplements coastal sediment deficits by introducing sand from outside of the active coastal system. Ship Shoal is an inner-shelf submarine shoal with large amounts of restoration quality sand that was dredged in 2013-2016 for the Caminada Headland Restoration Project in central Louisiana, USA.
Vibracore samples (1.5 - 3.5 m deep) collected in 2017 and 2018 in Caminada Borrow Area revealed new silts and …
Streambed Flux Measurement Informed By Distributed Temperature Sensing Leads To A Significantly Different Characterization Of Groundwater Discharge, Troy E. Gilmore, Mason Johnson, Jesse T. Korus, Aaron R. Mittelstet, Marty A. Briggs, Vitaly A. Zlotnik, Sydney Corcoran
Streambed Flux Measurement Informed By Distributed Temperature Sensing Leads To A Significantly Different Characterization Of Groundwater Discharge, Troy E. Gilmore, Mason Johnson, Jesse T. Korus, Aaron R. Mittelstet, Marty A. Briggs, Vitaly A. Zlotnik, Sydney Corcoran
Conservation and Survey Division: Faculty and Staff Publications
Groundwater discharge though streambeds is often focused toward discrete zones, indicating that preliminary reconnaissance may be useful for capturing the full spectrum of groundwater discharge rates using point-scale quantitative methods. However, many direct-contact reconnaissance techniques can be time-consuming, and remote sensing (e.g., thermal infrared) typically does not penetrate the water column to locate submerged seepages. In this study, we tested whether dozens of groundwater discharge measurements made at “uninformed” (i.e., selected without knowledge on high-resolution temperature variations at the streambed) point locations along a reach would yield significantly dierent Darcy-based groundwater discharge rates when compared with “informed” measurements, focused at …
Effects Of Reservoir Conditions And Trace Co-Contaminant Gases On Geological Carbon Sequestration, Ram Kumar
Effects Of Reservoir Conditions And Trace Co-Contaminant Gases On Geological Carbon Sequestration, Ram Kumar
USF Tampa Graduate Theses and Dissertations
Geological carbon sequestration in a saline formation is a promising technology for large-scale carbon dioxide (CO2) mitigation. Several factors such as temperature, pressure, salinity, hydraulic conductivity, and mineralogy of a formation affect the CO2 sequestration in saline formations. These factors can vary widely depending upon the type of formation or the degree of heterogeneity within a formation. In addition to these properties of the repositories, the CO2-rich flue gas streams captured from point sources often contains small amounts of impurities such as sulfur oxides (SOx) and nitrogen oxides (NOx), which may have serious implications on the chemistry of the repositories …