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2020

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Articles 241 - 270 of 405

Full-Text Articles in Geology

Vegetation Prior To And During Onset Of East Antarctic Glaciation: High Resolution Palynological Insights From Sabrina Coast, East Antarctica, Meghan L. Duffy Mar 2020

Vegetation Prior To And During Onset Of East Antarctic Glaciation: High Resolution Palynological Insights From Sabrina Coast, East Antarctica, Meghan L. Duffy

LSU Master's Theses

The Aurora Subglacial Basin (ASB) contains an estimated 3.5 m of global sea-level equivalent ice volume and is primarily drained by the Totten Glacier system, which terminates at the Sabrina Coast, East Antarctica. Thinning and retreating of the Totten Glacier indicate that this region is highly susceptible to oceanographic and atmospheric warming. The paleoclimate reconstruction of these changes, conducted in the context of this MS thesis, will improve understanding of East Antarctic Ice Sheet (EAIS) dynamics in this sensitive system. A recent study used seismic and sediment core data to document a dynamic early evolution of the EAIS in the …


The Role Of Floating Gardens To Alter The Water Quality Of The Chicago River: Chicago, Il, Emmett Andrew Spooner Mar 2020

The Role Of Floating Gardens To Alter The Water Quality Of The Chicago River: Chicago, Il, Emmett Andrew Spooner

Theses and Dissertations

The pollution of heavy metals within surface water is a rising global concern. As heavy metals are transported through rivers, they can bioaccumulate through the food web, leading to harmful concentrations within waterways. In urban areas such as the city of Chicago, Illinois, the use of road salts is a concern as elevated concentrations of chloride (Cl–) can reduce surface water quality. Since surface waters can carry heavy metals and Cl– salts over a large distance, methods of in-situ phytoremediation are of growing importance. Through a pilot project, a floating garden system has been installed along a portion of the …


High‐Pressure Carbonaceous Phases As Minerals, Oliver Tschauner Mar 2020

High‐Pressure Carbonaceous Phases As Minerals, Oliver Tschauner

Geoscience Faculty Research

High‐pressure carbonaceous minerals establish a link between one of the most abundant chemical elements and processes that occur at high pressures, either in the interior of the Earth or during shock‐metamorphosis in space or on Earth. Diamonds from the Earth's mantle carry inclusions of carbides, carbonates, methane, and carbon‐dioxide. These inclusions elucidate diamond formation and the carbon recycling in the mantle. This chapter focuses on these inclusion minerals themselves, the means of detection, and the reconstruction of pressure‐temperature conditions of their formation in the mantle.


Spatiotemporal Changes Of Microbial Community Assemblages And Functions In The Subsurface, Madison C. Davis Mar 2020

Spatiotemporal Changes Of Microbial Community Assemblages And Functions In The Subsurface, Madison C. Davis

USF Tampa Graduate Theses and Dissertations

The subsurface hosts diverse microbial community assemblages and functions. These communities play an important role in biogeochemical cycling and groundwater purification. Many physicochemical factors affect microbial communities and can cause short-term or long-term perturbations. Subsurface microbes are susceptible to anthropogenic changes in the environment, which can be caused by nutrient inputs or municipal groundwater extraction. Despite the importance of the subsurface microbiome, these microbial communities are poorly characterized. This dissertation describes the characterization of spatiotemporal drivers of subsurface microbial communities through a variety of techniques that include eDNA analyses, bioinformatics, hydrochemical analyses, stable isotope geochemistry, and multivariate statistics. Three coastal …


Constraining Prograde Metamorphic Paths In Archean High-Grade Garnet-Bearing Lithologies From The Eastern Beartooth Mountains, Montana, Usa, Larry Fisher Cliff-Tuttle Jr Mar 2020

Constraining Prograde Metamorphic Paths In Archean High-Grade Garnet-Bearing Lithologies From The Eastern Beartooth Mountains, Montana, Usa, Larry Fisher Cliff-Tuttle Jr

LSU Master's Theses

Prograde metamorphic pressures and temperatures of Archean high-grade garnet-bearing lithologies from the eastern Beartooth Mountains of Montana provide an important constraint on the tectonometamorphic history of this terrane and the early Earth in general. A particularly useful means to approximate prograde metamorphic conditions is examining entrapment conditions of garnet mineral inclusions during garnet growth. Lithologies of the eastern Beartooth Mountains are well-suited to this approach because of the presence of abundant mineral inclusions within garnet porphyroblasts. Consequently, prograde metamorphic pressures and temperatures in the Beartooth Mountains, conditions that have only been broadly constrained previously, can be more accurately determined and …


Critical Knowledge Gaps In The Martian Geological Record: A Rationale For Regional-Scale In Situ Exploration By Rotorcraft Mid-Air Deployment, William Rapin Sorbonne Université, A. Fraeman California Institute Of Technology, B. L. Ehlmann California Institute Of Technology, A. Mittelholz University Of British Columbia, B. Langlais, R. Lillis, V. Sautter, D. Baratoux, V. Payré, Arya Udry, B. Horgan, J. Flahaut, G. Dromart, C. Quantin-Nataf, N. Mangold, S. Maurice, J. T. Keane, J. Bapst Mar 2020

Critical Knowledge Gaps In The Martian Geological Record: A Rationale For Regional-Scale In Situ Exploration By Rotorcraft Mid-Air Deployment, William Rapin Sorbonne Université, A. Fraeman California Institute Of Technology, B. L. Ehlmann California Institute Of Technology, A. Mittelholz University Of British Columbia, B. Langlais, R. Lillis, V. Sautter, D. Baratoux, V. Payré, Arya Udry, B. Horgan, J. Flahaut, G. Dromart, C. Quantin-Nataf, N. Mangold, S. Maurice, J. T. Keane, J. Bapst

Geoscience Faculty Research

Mars oldest terrains hold the answers to key science questions, yet remain largely unexplored. In situ exploration by mid-air deployed rotorcrafts can uniquely answer these questions in the near future due to their unique ability to access the ancient southern highlands and perform in situ analyses at regional-scale, at breakthrough costs.


Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes, Melissa S. Chapot, Alexis K. Ault, Greg Hirth, Robert G. Mcdermott Mar 2020

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes, Melissa S. Chapot, Alexis K. Ault, Greg Hirth, Robert G. Mcdermott

Geosciences Faculty Publications

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick …


Evaluation Of The Potential Geological And Socioeconomic Impacts Of The Imminent Cascadia Megathrust Earthquake, Matthew Pritchard Mar 2020

Evaluation Of The Potential Geological And Socioeconomic Impacts Of The Imminent Cascadia Megathrust Earthquake, Matthew Pritchard

Honors Program: Senior Projects (Public)

The Cascadia Subduction Zone on the northwest coast of the United States poses the threat of a devastating megathrust earthquake and subsequent tsunami damaging coastal populations. This paper synthesizes literature to analyze the geologic and socioeconomic effects of this natural disaster, as well as examines the existing warning system infrastructure, and makes recommendations to mitigate the damage. In order to assess the geologic effects of a megathrust earthquake, I investigate the tectonic history, the role of episodic tremor and slip (ETS) in stress buildup, crustal architecture of the subduction zone, and analogous subduction zones such as Chile and Japan. This …


Characterizing Multiscale Geometry, Anisotropic Behaviors, Bulk Properties, And Wettability Of The Woodford Shale, Pratap Bohara Mar 2020

Characterizing Multiscale Geometry, Anisotropic Behaviors, Bulk Properties, And Wettability Of The Woodford Shale, Pratap Bohara

Graduate Student Council Research Grants

Overview: I am Pratap Bohara--a fourth year PhD student in the Department of Geology and Geological Engineering at the University of Mississippi. I define myself as a dedicated research fellow with more than seven years of experience in the field of Geology and Geological Engineering. The proposed study will integrate geology, geochemistry, and surface chemistry to advance understanding of oil and gas behavior within the Woodford Shale of Oklahoma.

Intellectual Merit: Although this unit has abundant kerogen, total organic carbon (TOC), a high hydrogen index (HI), a low oxygen index (OI), and is thermally mature seemingly making reservoir economic but …


Collaborative Research: Quantifying Crustal Hydration Effects In The Colorado Plateau From Xenoliths, Dennis Newell Mar 2020

Collaborative Research: Quantifying Crustal Hydration Effects In The Colorado Plateau From Xenoliths, Dennis Newell

Funded Research Records

No abstract provided.


Petrology, Physicochemical And Thermal Analyses Of Selected Cretaceous Coals From The Benue Trough Basin In Nigeria, S. A. Akinyemi, O. F. Adebayo, B. B. Nyakuma, A. K. Adegoke, O. A. Aturamu, O. A. Olaolorun, A. Adetunji, James C. Hower, Madison M. Hood, A. Jauro Mar 2020

Petrology, Physicochemical And Thermal Analyses Of Selected Cretaceous Coals From The Benue Trough Basin In Nigeria, S. A. Akinyemi, O. F. Adebayo, B. B. Nyakuma, A. K. Adegoke, O. A. Aturamu, O. A. Olaolorun, A. Adetunji, James C. Hower, Madison M. Hood, A. Jauro

Center for Applied Energy Research Faculty and Staff Publications

Abundant coal resources that were previously neglected due to a crude oil boom need revitalisation and integration into the national electricity mix to address the energy demands of the Nigerian population. Selected coal samples from the Benue Trough sedimentary basin in Nigeria were examined by various techniques, including proximate and ultimate analyses, organic petrography, Fourier transform infrared ray spectroscopy, and thermogravimetric analysis. Based on vitrinite reflectance, the Lafia-Obi (OLB), Garin Maiganga (GMG), Imiegba (IMG), and Okaba (OKB) coals are classified as subbituminous, while the Lamja1 (LMJ1), Lamja2 (LMJ2) and Chikila (CHK) coals are high volatile B bituminous. The Enugu (ENG) …


Groundwater Quality In The High Plains Aquifer Mar 2020

Groundwater Quality In The High Plains Aquifer

United States Geological Survey: Publications

Groundwater provides nearly 50 percent of the Nation’s drinking water. To help protect this vital resource, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project assesses groundwater quality in aquifers that are important sources of drinking water. The High Plains aquifer constitutes one of the important aquifers being evaluated.

The High Plains aquifer underlies an area of about 169,000 square miles, which is populated by about 2 million people in parts of eight western states (Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, South Dakota, and Wyoming). The aquifer ranks 13th in the Nation as a source of groundwater for …


Rockhounding, Seafaring, And Other Material Tales For The End Of The World, Noemie Fortin Mar 2020

Rockhounding, Seafaring, And Other Material Tales For The End Of The World, Noemie Fortin

The Goose

In the face of accelerated environmental degradation and climate instability, the future of the Earth and of all life on earth is difficult to visualize. Therefore, the different mediums through which we consider environmental issues are just as important as the actions we take to address them. Focusing on three projects combining art, science, and activism, this article suggests a compilation of material tales. They tell stories of plastic rocks and aluminum nuggets where the protagonists are partly finely crafted objects, partly waste materials, and sometimes both at once. Artists Kelly Jazvac, Yesenia Thibeault-Picazo, and the collective Studio Swine collaborate …


Receiver Function Imaging Of The 410 And 660 Km Discontinuities Beneath The Australian Continent, Kailun Ba, Stephen S. Gao, Kelly H. Liu, Fansheng Kong, Jianguo Song Mar 2020

Receiver Function Imaging Of The 410 And 660 Km Discontinuities Beneath The Australian Continent, Kailun Ba, Stephen S. Gao, Kelly H. Liu, Fansheng Kong, Jianguo Song

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To provide constraints on a number of significant controversial issues related to the structure and dynamics of the Australian continent, we utilize P-to-S receiver functions (RFs) recorded by 182 stations to map the 410 and 660 km discontinuities (d410 and d660, respectively) bordering the mantle transition zone (MTZ). The RFs are stacked in successive circular bins with a radius of 1° under a non-plane wave front assumption. The d410 and d660 depths obtained using the 1-D IASP91 earth model show a systematic apparent uplifting of about 15 km for both discontinuities in central and western Australia relative to eastern Australia, …


Pleistocene/Holocene Cave Fossils From Grand Canyon National Park: Ice Age (Pleistocene) Flora, Fauna, Environments, And Climate Of The Grand Canyon, Arizona, Jim I. Mead, Justin S. Tweet, Vincent L. Santucci, Benjamin Tobin, Carol L. Chambers, Shawn C. Thomas, Mary C. Carpenter Mar 2020

Pleistocene/Holocene Cave Fossils From Grand Canyon National Park: Ice Age (Pleistocene) Flora, Fauna, Environments, And Climate Of The Grand Canyon, Arizona, Jim I. Mead, Justin S. Tweet, Vincent L. Santucci, Benjamin Tobin, Carol L. Chambers, Shawn C. Thomas, Mary C. Carpenter

Faculty, Staff, and Affiliated Publications--KGS

The Colorado Plateau is a distinct physiographic province in western North America covering an area of roughly 337,000 km2 (130,115 mi2) across parts of Arizona, Colorado, New Mexico, and Utah. Elevations range from about 360 m (1,180 ft) in the overall Grand Canyon (GC; which includes the Grand Canyon National Park, GRCA) river corridor to an average at the eastern South Rim of 2,072 m (6,800 ft) to 3,850 m (12,630 ft) on the nearby San Francisco Peaks at Flagstaff, Arizona, with an average elevation of 1,525 m (5,000 ft). The Colorado River of Grand Canyon is …


A New Early Occurrence Of Cervidae In North America From The Miocene-Pliocene Ellensburg Formation In Washington, Usa, Meaghan M. Emery-Wetherell, Joseph F. Schilter Mar 2020

A New Early Occurrence Of Cervidae In North America From The Miocene-Pliocene Ellensburg Formation In Washington, Usa, Meaghan M. Emery-Wetherell, Joseph F. Schilter

All Faculty Scholarship for the College of the Sciences

A new fossil cervid from the Craig’s Hill locality of the Miocene-Pliocene Ellensburg Formation in the State of Washington, USA, may be one of the oldest fossil deer yet found in North America, underlying a date of 4.9 Ma ± 0.1 Ma. This mandible fragment with m2, m3, and associated p2 has a size that does not distinguish it from Bretzia pseudalces, Odocoileus hemionus, or Capreolus constantini, and distinguishes it from Eocoileus gentryorum and Odocoileus lucasi only in having a thinner p2. A strong paraconid on the p2, and ectostylids and cingulids on the m2 and m3 link it most …


Petrology, Geochronology, And Geophysical Characterization Of Mesoproterozoic Rocks In Central Illinois, Usa, Jared T. Freiburg, John H. Mcbride, David H. Malone, Hannes E. Leetaru Mar 2020

Petrology, Geochronology, And Geophysical Characterization Of Mesoproterozoic Rocks In Central Illinois, Usa, Jared T. Freiburg, John H. Mcbride, David H. Malone, Hannes E. Leetaru

Faculty Publications - Geography, Geology, and the Environment

The Precambrian basement rocks of the Eastern Granite-Rhyolite Province (EGRP) in central Illinois (midcontinent region of North America) exhibit a complex history of early volcanism, granite emplacement, and intrusion of mafic rocks. A comprehensive suite of dedicated petrographic analyses, geophysical logs, and drill core from four basement-penetrating wells, two-dimensional and three-dimensional seismic reflection data, and U-Pb age data from the Illinois Basin–Decatur Project (IBDP) and Illinois Carbon Capture Storage (ICCS) Project site provide new constraints for interpreting the Precambrian basement of the Illinois Basin. These new data reveal the basement to be compositionally and structurally complex, having typical EGRP felsic …


Crustal Composition And Moho Variations Of The Central And Eastern United States: Improving Resolutionand Geologic Interpretation Of Earthscope Usarray Seismic Images Using Gravity, H. L. Zhang, D. Ravat, Anthony R. Lowry Feb 2020

Crustal Composition And Moho Variations Of The Central And Eastern United States: Improving Resolutionand Geologic Interpretation Of Earthscope Usarray Seismic Images Using Gravity, H. L. Zhang, D. Ravat, Anthony R. Lowry

Geosciences Faculty Publications

EarthScope's USArray Transportable Array has shortcomings for the purpose of interpreting geologic features of wavelengths less than the Transportable Array station spacing, but these can be overcome by using higher spatial resolution gravity data. In this study, we exploit USArray receiver functions to reduce nonuniqueness 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 …


Mechanisms Of Carbon Movement And Stabilization In Mangrove Wetlands, Carey Schafer Feb 2020

Mechanisms Of Carbon Movement And Stabilization In Mangrove Wetlands, Carey Schafer

USF Tampa Graduate Theses and Dissertations

Mangrove forests have higher rates of carbon storage per unit area than any other coastal or terrestrial habitat, largely due to their significant soil stocks. More effort has been placed on quantifying mangrove soil carbon stock, the amount of carbon stored in the upper meter of mangrove soils, than identifying the processes governing in situ soil organic carbon (SOC) cycling and stabilization. An understanding of the mechanisms related to carbon transport and stability is necessary to constrain current wetland carbon stocks and to determine how sea level rise will impact future carbon stores. This study uses a variety of radiometric …


Detrital Zircon Provenance And Lithofacies Associations Of Montmorillonitic Sands In The Maastrichtian Ripley Formation: Implications For Mississippi Embayment Paleodrainage Patterns And Paleogeography, Jennifer N. Gifford, Elizabeth J. Vitale, Brian F. Platt, David H. Malone, Inoka H. Widanagamage Feb 2020

Detrital Zircon Provenance And Lithofacies Associations Of Montmorillonitic Sands In The Maastrichtian Ripley Formation: Implications For Mississippi Embayment Paleodrainage Patterns And Paleogeography, Jennifer N. Gifford, Elizabeth J. Vitale, Brian F. Platt, David H. Malone, Inoka H. Widanagamage

Faculty Publications - Geography, Geology, and the Environment

We provide new detrital zircon evidence to support a Maastrichtian age for the establishment of the present-day Mississippi River drainage system. Fieldwork conducted in Pontotoc County, Mississippi, targeted two sites containing montmorillonitic sand in the Maastrichtian Ripley Formation. U-Pb detrital zircon (DZ) ages from these sands (n = 649) ranged from Mesoarchean (~2870 Ma) to Pennsylvanian (~305 Ma) and contained ~91% Appalachian-derived grains, including Appalachian–Ouachita, Gondwanan Terranes, and Grenville source terranes. Other minor source regions include the Mid-Continent Granite–Rhyolite Province, Yavapai–Mazatzal, Trans-Hudson/Penokean, and Superior. This indicates that sediment sourced from the Appalachian Foreland Basin (with very minor input from a …


Hydrogeologic Framework And Water Balance Investigation Of Land Near The Gothenburg Canal System, Douglas R. Hallum Feb 2020

Hydrogeologic Framework And Water Balance Investigation Of Land Near The Gothenburg Canal System, Douglas R. Hallum

Conservation and Survey Division: Faculty and Staff Publications

The Nebraska Public Power District (NPPD) requested that Conservation and Survey Division (CSD) develop a local hydrogeologic framework and conceptual water budget for a parcel of land near a segment of canal in the Gothenburg Canal System to determine likely sources of ponded surface water that are ephemerally present on the parcel. The study seeks to assess the parcel scale water budget and to better understand the parcel-scale hydrology and hydrogeology. The object of this project is to provide reliable information to NPPD and its customers along a small portion of the canal. Information from this report may influence, or …


Geology Of Nacogdoches, Texas: Texas Academy Of Science March 1, 2020, R. Larell Nielson, Mike Read, Mindy Faulkner, Hannah C. Chambers, Jessica O'Neal Feb 2020

Geology Of Nacogdoches, Texas: Texas Academy Of Science March 1, 2020, R. Larell Nielson, Mike Read, Mindy Faulkner, Hannah C. Chambers, Jessica O'Neal

Faculty Publications

No abstract provided.


Shallow Water Seafloor Geodesy: Gps On An Anchored Spar Buoy, Surui Xie Feb 2020

Shallow Water Seafloor Geodesy: Gps On An Anchored Spar Buoy, Surui Xie

USF Tampa Graduate Theses and Dissertations

Measuring seafloor motion in shallow coastal water is challenging due to strong and highly variable oceanographic effects. Such measurements are potentially useful for monitoring near-shore coastal subsidence, subsidence due to petroleum withdrawal, strain accumulation/release processes in marine shelves and submerged volcanoes, and certain fresh water applications, such as volcano deformation in caldera-hosted lakes. I participated in a project to develop a seafloor geodetic system for this environment based on an anchored spar buoy topped by high precision GPS. Orientation of the buoy is measured using a digital compass that provides heading, pitch, and roll information. The combined orientation and GPS …


Mauvais Coulee Basin Hydrologic Data (Observation And Simulation), Diane F. Van Hoy, Taufique H. Mahmood, Paul E. Todhunter, Tyson L. Jeannotte Feb 2020

Mauvais Coulee Basin Hydrologic Data (Observation And Simulation), Diane F. Van Hoy, Taufique H. Mahmood, Paul E. Todhunter, Tyson L. Jeannotte

Datasets

The authors collected snow water equivalent (SWE) data and compiled a hydrologic model for the Mauvais Coulee Basin using Cold Region Hydrologic Platform. The datasets include observed SWE, observed streamflow, simulated SWE, simulated streamflow, simulated SWE maps (Feb 26, Jan 29, Jan 8 and Mar 26 of 2017), land use maps and hydrological representative unit maps (HRU) maps. This study detected a mechanism of hydrologic change to recent wetting using a cold region hydrologic model.


Mammoth Onyx Cave - Relating To (Sc 3504), Manuscripts & Folklife Archives Feb 2020

Mammoth Onyx Cave - Relating To (Sc 3504), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "Additional Files" below) for Manuscripts Small Collection 3504. Letter, 15 August 1922, of Charles A. Richardson, Assistant Geologist, Kentucky Geological Survey, to Dr. Harry B. Thomas, Horse Cave, Kentucky, regarding his recent study of the formations in Mammoth Onyx Cave, then owned by Thomas. He remarks on the “abundance of Mexican Onyx, or Onyx Marble” and the beauty of the stalactites and stalagmites. Includes a pamphlet by Leon Foster with his impressions of the cave, which was opened to the public in 1922.


New Magnetic Field Models Of The Moon, Dhananjay Ravat, Michael E. Purucker, Nils Olsen Feb 2020

New Magnetic Field Models Of The Moon, Dhananjay Ravat, Michael E. Purucker, Nils Olsen

Earth and Environmental Sciences Research Data

We use L1-norm model regularization of |Br| component at the surface on magnetic monopoles bases and along-track magnetic field differences alone (without vector observations) to derive high quality global magnetic field models at the surface of the Moon. The practical advantages to this strategy are: monopoles are more stable at closer spacing in comparison to dipoles, improving spatial resolution; L1-norm model regularization leads to sparse models which may be appropriate for the Moon which has regions of localized magnetic field features; and along-track differences reduce the need for ad-hoc external field noise reduction strategies. We examine also the …


Geochronology Of The Middle Eocene Purple Bench Locality (Devil’S Graveyard Formation), Trans-Pecos Texas, Usa, Amy L. Atwater, Kelly D. Thomson, E. Christopher Kirk, Meaghan Emery-Wetherell, Logan Wetherell, Daniel F. Stockli Feb 2020

Geochronology Of The Middle Eocene Purple Bench Locality (Devil’S Graveyard Formation), Trans-Pecos Texas, Usa, Amy L. Atwater, Kelly D. Thomson, E. Christopher Kirk, Meaghan Emery-Wetherell, Logan Wetherell, Daniel F. Stockli

All Faculty Scholarship for the College of the Sciences

Purple Bench is a middle Eocene fossil locality in the Devil’s Graveyard Formation of the Trans-Pecos region of West Texas. In addition to yielding a range of taxa characteristic of the Uintan North American Land Mammal Age, the Purple Bench locality is noteworthy in documenting a number of endemic species that are known only from the site. Despite the Uintan character of the mammalian fauna, the absolute age of Purple Bench is a matter of debate. This uncertainty stems from the wide interval of time encompassed by current radiometric dates bracketing the Purple Bench locality and from conflicting magnetostratigraphic correlations …


Mantle Structure And Flow Beneath An Early-Stage Continental Rift: Constraints From P Wave Anisotropic Tomography, Youqiang Yu, Stephen S. Gao, Dapeng Zhao, Kelly H. Liu Feb 2020

Mantle Structure And Flow Beneath An Early-Stage Continental Rift: Constraints From P Wave Anisotropic Tomography, Youqiang Yu, Stephen S. Gao, Dapeng Zhao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To explore 3-D seismic velocity and radial anisotropy structures of the upper mantle and mantle transition zone beneath the Malawi and Luangwa rift zones of the East African Rift System, we conduct the first study of P wave anisotropic tomography using data recorded at 75 seismic stations including 34 stations that we installed along two profiles as part of the Seismic Arrays for African Rift Initiation experiment. Both rift zones are revealed to have normal or slightly low velocity anomalies in the lithosphere and upper asthenosphere. The surrounding cratonic lithosphere is characterized by high-velocity anomalies with amplitudes ranging from +1.0% …


Mapping The Base Of The High Plains Aquifer Using Borehole Geophysical Logs And Airborne Electromagnetic Surveys In Western Nebraska, Steven S. Sibray, Douglas R. Hallum, Joseph Reedy, Jason Yuill, Thadeus Kuntz Feb 2020

Mapping The Base Of The High Plains Aquifer Using Borehole Geophysical Logs And Airborne Electromagnetic Surveys In Western Nebraska, Steven S. Sibray, Douglas R. Hallum, Joseph Reedy, Jason Yuill, Thadeus Kuntz

Conservation and Survey Division: Faculty and Staff Publications

The project scanned and reviewed data from 15,421 oil and gas well geophysical logs in 13 counties to delineate the base of aquifer and thickness of the High Plains Aquifer (HPA). The data and interpretations from this study can be used in a regional groundwater modeling effort that includes the Western Water Use Management Modeling (WWUMM) and the and the Cooperative Hydrology Study (COHYST) model. The area studied is in the Upper Platte River Basin. The Nebraska Department of Natural Resources (NeDNR) has designated most of the area as either overappropriated or fully appropriated, where groundwater is managed jointly

by …


Reshuffling The Columbia River Basalt Chronology — Picture Gorge Basalt, The Earliest- And Longest-Erupting Formation, Emily B. Cahoon, Martin J. Streck, Anthony A.P. Koppers, Daniel P. Miggins Jan 2020

Reshuffling The Columbia River Basalt Chronology — Picture Gorge Basalt, The Earliest- And Longest-Erupting Formation, Emily B. Cahoon, Martin J. Streck, Anthony A.P. Koppers, Daniel P. Miggins

Geology Faculty Publications and Presentations

The Columbia River Basalt Group (CRBG) is the world’s youngest continental flood basalt province, presumably sourced from the deep-seated plume that currently resides underneath Yellowstone National Park in the northwestern United States. The earliest-erupted basalts from this province aid in understanding and modeling plume impingement and the subsequent evolution of basaltic volcanism. We explore the Picture Gorge Basalt (PGB) formation of the CRBG, and discuss the location and geochemical significance in a temporal context of early CRBG magmatism. We report new ARGUS-VI multicollector 40Ar/39Ar incremental heating ages from known PGB localities and additional outcrops that we can geochemically classify as …