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Full-Text Articles in Geology

Environments And Controls Of Erosional Bedforms In Soluble Channels, Ethan W. Oleson Aug 2024

Environments And Controls Of Erosional Bedforms In Soluble Channels, Ethan W. Oleson

Graduate Theses and Dissertations

Erosional bedforms, such as scallops, preserve valuable information on the paleohydrologic conditions forming soluble channels in karst systems. While these bedforms are commonly used to interpret past conditions, questions about their formation remain. Mathematical models of speleogenesis in turbulent flow predict that the conditions for forming scallops do not occur in natural carbonate systems. However, scallops are readily found in caves throughout the world. This conundrum has several possible resolutions, but each lacks field-based observations. We present a field-based study of the environments and controls of scallops in gypsum, limestone, and dolostone caves. Our results are based on field observation, …


Dynamics Of Climate And Tectonics On Surface Processes And Their Sedimentary Archives In The Colorado Plateau And Basin And Range, Usa And The Calabrian Forearc, Sicily, Natalie M. Tanski Aug 2024

Dynamics Of Climate And Tectonics On Surface Processes And Their Sedimentary Archives In The Colorado Plateau And Basin And Range, Usa And The Calabrian Forearc, Sicily, Natalie M. Tanski

All Graduate Theses and Dissertations, Fall 2023 to Present

Landscapes change over time in response to movements of the Earth’s crust and the effects of climate. This dissertation examines how these factors shape different landscapes, focusing on erosion of river canyons in elevated plateaus, how the transport history in quartz sand may be encoded in its properties, and how a paleo-delta has formed in response to sea-level change and fault displacement. I use dating techniques, field methods, and topographic analyses to offer insight into erosional patterns and rates in different landscapes.

Rivers can take a long time to adjust to changes in boundary conditions, even after those changes have …


Silica Fault Mirror Development Along The Cordillera Blanca Detachment Fault, Peru, Kayla Michelle Chaudoir Aug 2024

Silica Fault Mirror Development Along The Cordillera Blanca Detachment Fault, Peru, Kayla Michelle Chaudoir

All Graduate Theses and Dissertations, Fall 2023 to Present

Earthquakes occur along planes of geologic weakness called faults. Thin, light-reflective surfaces on faults are called fault mirrors and often considered signatures of previous earthquakes along these faults. The Cordillera Blanca mountain range in the Peruvian Andes provides a natural laboratory to explore meter scale exposures of fault mirrors. Three naturally formed fault mirror samples were collected from the Cordillera Blanca detachment fault which runs along the edge of the Cordillera Blanca mountain range. Prior work on this fault reveals that it is capable of destructive earthquakes every few thousand years and is a significant earthquake hazard to the surrounding …


Hydrogen Stable Isotope Constraints On Hydration Of Colorado Plateau Lower Crust From Oligocene-Miocene Navajo Volcanic Field Xenoliths, Shelby Dianne Litton Aug 2024

Hydrogen Stable Isotope Constraints On Hydration Of Colorado Plateau Lower Crust From Oligocene-Miocene Navajo Volcanic Field Xenoliths, Shelby Dianne Litton

All Graduate Theses and Dissertations, Fall 2023 to Present

Understanding flat-slab subduction is crucial as it involves the horizontal movement of an oceanic plate beneath a continental margin over a long distance. This tectonic process is widespread yet not fully understood, particularly regarding how it influences the chemical makeup of the continental plate and recycling in the hydrosphere. By analyzing isotopes, which are variations of certain elements found in minerals and water, we can gain insights into the sources of chemicals and geological processes at play. Our study area included six locations within the Navajo volcanic field (NVF), a region in the Colorado Plateau. We analyzed 23 lower crustal …


Shaking Off The Rust: Unraveling The Depositional And Diagenetic History Of Enigmatic Ferroan Dolostones In The Cambrian Bright Angel Formation, Tonto Group, Grand Canyon, Joseph J. Clevenger Aug 2024

Shaking Off The Rust: Unraveling The Depositional And Diagenetic History Of Enigmatic Ferroan Dolostones In The Cambrian Bright Angel Formation, Tonto Group, Grand Canyon, Joseph J. Clevenger

All Graduate Theses and Dissertations, Fall 2023 to Present

Within the siliciclastic-sediment-dominated Bright Angel Formation (BAF) of the iconic Cambrian sedimentary strata (Tonto Group) in Grand Canyon National Park, Arizona, workers have identified and named prominent reddish-brown cliffs breaking up the generally slope-forming unit near, but separated from, its upper contact with the limestone-dominated Muav Formation, the "Rusty Brown Dolostones" (RBDs). Previous hypotheses suggest that the RBDs are chemically and physically altered tongues of the Muav Formation intercalated with the BAF at increasingly higher stratigraphic positions from west to east within the Canyon. A genetic association between the Muav Formation and the RBDs, as well as between the RBDs …


New Insights Into The Diverse Intraplate Volcanism Present Within The Howland And Baker Island United States Exclusive Economic Zone, Nicholas Foresta Aug 2024

New Insights Into The Diverse Intraplate Volcanism Present Within The Howland And Baker Island United States Exclusive Economic Zone, Nicholas Foresta

UNLV Theses, Dissertations, Professional Papers, and Capstones

The origin of oceanic volcanism has been attributed to various mechanisms, such as upwelling mantle plumes, lithospheric extension driven decompression melting, and small-scale convective cells in the asthenosphere. Discovering the range of magmatic drivers present in the ocean basins aids in understanding mantle geodynamics and tectonic processes. A recent seafloor exploration campaign within the Howland and Baker Island (HBI) U.S. Exclusive Economic Zone (EEZ; approximately near the equator and the International Date Line) resulted in the collection of multiple lava flow samples, which offer valuable insights into the complex origins and dynamics of intraplate seamounts. According to current absolute plate …


Phylogenetic And Biogeographic Patterns Of Devonian Proetid Trilobites, Katherine Jane Jordan Aug 2024

Phylogenetic And Biogeographic Patterns Of Devonian Proetid Trilobites, Katherine Jane Jordan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Ecological disruption events such as mass extinctions can result in the permanent alteration in clades and ecosystems. A pivotal time of change during the history of life on Earth can be seen in the Devonian Period. During this time, major transitions in marine and terrestrial system resulted in a different world at the end of the period in comparison to the beginning. One such group most heavily impacted were trilobites. Trilobites were reduced to one order by the end of the Devonian: Proetida. My dissertation focuses on phylogenetic, biogeographic, and paleocommunity patterns of this group, known as the last of …


Effects Of Climate Change On (Semi)-Arid Ecosystems In The Southwestern United States, Charlotte Van Der Nagel Aug 2024

Effects Of Climate Change On (Semi)-Arid Ecosystems In The Southwestern United States, Charlotte Van Der Nagel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate change is considered amongst the most severe threats to terrestrial and aquatic ecosystems globally. Ecosystems in the southwestern United States have specifically been impacted by intense drought conditions since 2000. Higher temperatures combined with altered precipitation stresses many ecosystems; however, ecosystem specific responses to such stressors may vary. Here, the effects of climate change on semi-arid ecosystems are analyzed for some of the most vulnerable ecosystems in the southwestern United States: lacustrine, riparian, and dryland ecosystems.

Lakes and reservoirs in arid environments often serve as drinking water sources and recreational areas where high water quality is essential. Climate change …


Differential River Incision Due To Quaternary Faulting On The Río Jemez-Salado System At The Million-Year Timescale, Cameron Reed Jul 2024

Differential River Incision Due To Quaternary Faulting On The Río Jemez-Salado System At The Million-Year Timescale, Cameron Reed

Earth and Planetary Sciences ETDs

Analysis of long-term average bedrock incision rates along the Río Salado-Jemez system using fluvial terraces can be used to test and quantify the hypothesis that differential river incision reflects Quaternary fault slip during ongoing uplift of the Jemez and Nacimiento Mountains. Terrace flights were correlated from the Arroyo Peñasco to the Río Salado near the southern nose of the Nacimiento and along the Río Jemez. Using highest/oldest river terraces, resulting bedrock incision values average out glacial/interglacial cycles and are interpreted to reflect differential uplift. For previously mapped and correlated terraces, we applied lidar datasets to refine strath heights. We also …


Constraining The Evolutionary Stages Of A Hypogene Karst System By Combining Morphological, Geochemical And Geochronological Data - The Example Of Carbonate Breccia-Hosted Melnička Peštera, Marjan Temovski, Zsófia Ruszkiczay-Rüdiger, Kata Molnár, László Rinyu, Alexander Wieser, Oscar Marchhart, László Palcsu Jul 2024

Constraining The Evolutionary Stages Of A Hypogene Karst System By Combining Morphological, Geochemical And Geochronological Data - The Example Of Carbonate Breccia-Hosted Melnička Peštera, Marjan Temovski, Zsófia Ruszkiczay-Rüdiger, Kata Molnár, László Rinyu, Alexander Wieser, Oscar Marchhart, László Palcsu

International Journal of Speleology

A combination of morphological observations, geochemical data from calcite minerals and geochronology by burial age dating and U-series is used to constrain the geological and geomorphological setting and the evolutionary stages of a hypogene karst system. This methodological suit is applied to Melnička Peštera, a horizontal cave developed in carbonate breccia overlying dolomite marble in Melnica locality (N. Macedonia), where hydrothermal karst development occurred in both dolomite and calcite marble. The passage morphology of the cave, having a reverse triangle, Laughöhle cross-sections, suggests development near the water table by slowly moving waters. Calcite crusts are found throughout the cave, and …


Proterozoic Tectonic Evolution Of The Lower Granite Gorge, Grand Canyon, Arizona: A Middle Crustal Record Of Multiple Orogenic Pulses, John M. Bailey Jul 2024

Proterozoic Tectonic Evolution Of The Lower Granite Gorge, Grand Canyon, Arizona: A Middle Crustal Record Of Multiple Orogenic Pulses, John M. Bailey

Earth and Planetary Sciences ETDs

The well-exposed basement transect in the Lower Granite Gorge (LGG) of western Grand Canyon provides a middle-crustal record of suturing crustal blocks during the Proterozoic accretionary history of southwestern Laurentia. Orogenic evolution included at least three stages: (1) subduction-related ~1.75-1.72 Ga volcanic arc magmatism, turbidite deposition, and suturing of arc terranes with different crustal thicknesses; (2) intense northwest-southeast crustal shortening at ca. 1.71-1.68 Ga to form the Vishnu Mountains during the Yavapai orogeny; (3) dextral strike-slip shear zones development at ~1.4 Ga during long-term crustal residence and slow cooling above ~250 °C (~10 km) until ~1.3 Ga. Final cooling from …


Chemical And Morphological Characterization Of Airborne Particulate Matter At The Jackpile-Paguate Mine, Pueblo Of Laguna, New Mexico: Implications For Potential Metals Exposure, Andreanna C. Roros Jul 2024

Chemical And Morphological Characterization Of Airborne Particulate Matter At The Jackpile-Paguate Mine, Pueblo Of Laguna, New Mexico: Implications For Potential Metals Exposure, Andreanna C. Roros

Earth and Planetary Sciences ETDs

The inhalation of windblown particulate matter (PM) derived from abandoned uranium mines (AUMs) is a potential environmental health risk to Native American communities that live in proximity to these sites. However, the aeolian transport of metal-bearing PM from AUMs, as a potential exposure pathway, has not been investigated in any detail. In this study, we sampled airborne particulate matter within the Jackpile Mine located on the lands of the Pueblo of Laguna, New Mexico using passive sampling methods to understand the characteristics of dust within the mine site. The objective was to determine the elemental concentrations, mineralogy, and morphology of …


Sulfur Sequestration In Anhydrite Through Alteration Of Calcic Wall Rock, Lexi Kenis Jul 2024

Sulfur Sequestration In Anhydrite Through Alteration Of Calcic Wall Rock, Lexi Kenis

Earth and Planetary Sciences ETDs

Heterogeneous gas-solid reactions are suggested as a potential mecha-
nism for sequestering gaseous sulfur through the alteration of calcic wall
rocks. This study explores the concept of a “hierarchy of reactions” pro-
posed by Giggenbach (1987), outlining the interplay between gas components
and redox-related minerals in volcanic wall rocks. Mt. Pinatubo provides a
more felsic composition and more oxidizing conditions compared to previ-
ously studied volcanoes, Kudryavy and Erta Ale (Henley and Fischer, 2021),
and Lascar a more oxidizing case with a similar composition. By employing
thermodynamic models and synthetic melt experiments, evaluations of effi-
ciency of sulfur sequestration across …


Carbonate And Organic Proxies And The Impacts Of Climate On Lake Systems: Paleoclimate Interpretations From Lake Chalco, Mexico, Aria Holmes Jul 2024

Carbonate And Organic Proxies And The Impacts Of Climate On Lake Systems: Paleoclimate Interpretations From Lake Chalco, Mexico, Aria Holmes

Earth and Planetary Sciences ETDs

This project incorporates several lines of evidence to better understand the climate at Lake Chalco. Chapter 1 utilizes oxygen isotopes from carbonates and show that the Inter Tropical Convergence Zone varies on primarily glacial and millennial timescales; precession is not observed. These data indicate glacials periods were shallower and interglacials were wetter periods at Lake Chalco. Chapter 2 studies carbon, nitrogen, C/N, and TOC proxies and finds that the lake conditions during the glacials and interglacials are primarily a mixed algal-macrophyte-terrestrial organic matter. Deviations show that the lake during the interglacials had more algal organic matter- reflecting influxes of nutrients …


Sand, Ice, And X-Rays: Developing Xct Methods For Frozen Samples And Refining Siliciclastic Facies Models For Perennially Ice-Covered Lakes, Utilizing Cores From Lake Fryxell, Mcmurdo Dry Valleys, Antarctica, Holly M. Levett Jul 2024

Sand, Ice, And X-Rays: Developing Xct Methods For Frozen Samples And Refining Siliciclastic Facies Models For Perennially Ice-Covered Lakes, Utilizing Cores From Lake Fryxell, Mcmurdo Dry Valleys, Antarctica, Holly M. Levett

Earth and Planetary Sciences ETDs

Sedimentation in perennially ice-covered lakes (PICLs) is proposed to be bi-modal, with mud deposited by stream inflow and sand deposited on the ice cover by aeolian processes and then melting through by absorption of solar radiation. Here, we consider Lake Fryxell, a PICL in the McMurdo Dry Valleys, and several lake bed cores about 30 cm in length, to better understand PICL facies through time, using micro X-ray CT (XCT). Using XCT images along with sieve and laser granulometry data, we constrained the grain-size of PICL deposits to dominantly medium / fine sand with a coarse component. The presence of …


Chemical And Physical Properties Of Fine Fractions From A Village Proximate To A Uranium Mine: Insights About Soil Health, Mary P. Haley Jul 2024

Chemical And Physical Properties Of Fine Fractions From A Village Proximate To A Uranium Mine: Insights About Soil Health, Mary P. Haley

Nanoscience and Microsystems ETDs

Thousands of abandoned uranium mines (AUM) in Native American tribal lands have not been fully remediated, leaving uranium mine wastes exposed and accessible for potential erosion and transport by wind. Analyzing the metal and organic content of the fine-grained fractions in soils could uncover the impact of mine legacy on the soil health in communities that live in proximity to AUM. This study investigates the physical and chemical properties of the fine-grained fraction (μm) of soils to quantify the effect of heavy metal-bearing particulates on the soil health in the village of Paguate and within the Jackpile-Paguate AUM located on …


Historical Structural Analysis Of The Rileyville Quadrangle, Page County, Virginia, Sydney Fergen Jul 2024

Historical Structural Analysis Of The Rileyville Quadrangle, Page County, Virginia, Sydney Fergen

2024 Symposium

The Northwest corner of Virginia, within the Appalachian Mountains, formed during a collision of continents called the Alleghenian Orogeny roughly 250 million years ago(Ma). This event caused tectonic plates to collide, reforming the fractured continental crust back into a new supercontinent, Pangaea. This process took over 100 Ma and closed the Rheic Ocean. These large-scale compressional tectonics had several effects including formation of the Allegheny Plateau and Taconic Mountain range, which has gradually eroded exposing a series of plunging folds and imbricated thrust faults. This poster presents a structural analysis of the Rileyville quadrangle to help decipher regional geologic history …


U/Pb Zircon Ages Of Saltese Upland Conservation Area, Priest River Core Complex, Jessica M. Lawrence, Natalie Potter, Chad Pritchard Jul 2024

U/Pb Zircon Ages Of Saltese Upland Conservation Area, Priest River Core Complex, Jessica M. Lawrence, Natalie Potter, Chad Pritchard

2024 Symposium

The Saltese Upland Conservation Area provides a window into the Priest River Core Complex with Lake Hauser gneiss grading to migmatite, garnet-baring amphibolite juxtaposed with felsite to orthogneiss rocks. U/Pb ages from LA-ICP-MS of separated zircon grains show trends very similar to detrital 207Pb/206Pb ages of the Belt Supergroup. The amphibolite displays a much stronger peak at 1.4 to 1.5 Ga , possibly related to the emplacement of Mesoproterozoic dikes. The amphibolite and granitic rocks also contain a number of grains with 238U/206Pb around 60 Ma preserving events from the uplift of the Priest River Complex in the Spokane area. …


Paleohydraulic Analysis Of Megaripples From Outburst Floods In Omak, Washington, Jessica M. Lawrence Jul 2024

Paleohydraulic Analysis Of Megaripples From Outburst Floods In Omak, Washington, Jessica M. Lawrence

2024 Symposium

Located in Omak, Washington atop what is observed to be a gravel point bar are giant current ripples associated with outburst floods that took place during the Pleistocene (O’Connor et al. 2020 and Minard 1985). Thorough breakdown of these giant current ripples was conducted using their geomorphologies associated with stream flow mechanisms for gravel bedforms such as hydraulic radius of cross- sectional area and velocity using Manning’s equation to determine Froude’s Number (USDA 2007). Ripple index associated with ripple wavelength and height was then compared to additional megaripples located throughout Scablands of Washington that have been correlated to the Great …


Preliminary Analysis Of Per-And Polyfluoroalkyl Substances (Pfas) In Surface Waters Of The West Plains Region Of Spokane County, Jerusha Hampson Jul 2024

Preliminary Analysis Of Per-And Polyfluoroalkyl Substances (Pfas) In Surface Waters Of The West Plains Region Of Spokane County, Jerusha Hampson

2024 Symposium

Per-and Polyfluoroalkyl Substances (PFAS) have become a national issue as regulatory limits for these toxins have just recently been put into the Clean Water Act. The West Plains has been significantly impacted by PFAS contamination due to the decades-long use of aqueous film-forming foam (AFFF) for firefighting training at both Fairchild Airforce Base and the Spokane International Airport. Though research is still underway, it is known that PFAS contamination in West Plains groundwater is significant and widespread. This study focuses on West Plains surface waters, as there is currently less information about how these water bodies are impacted by PFAS. …


Numerical Simulations Suggest Asteroids (101955) Bennu And (162173) Ryugu Are Likely Second Or Later Generation Rubble Piles., K J Walsh, R-L Ballouz, W F Bottke, C Avdellidou, Harold Connolly Jr., M Delbo, D N Dellagiustina, E R Jawin, T Mccoy, P Michel, T Morota, M C Nolan, S R Schwartz, S Sugita, D S Lauretta Jul 2024

Numerical Simulations Suggest Asteroids (101955) Bennu And (162173) Ryugu Are Likely Second Or Later Generation Rubble Piles., K J Walsh, R-L Ballouz, W F Bottke, C Avdellidou, Harold Connolly Jr., M Delbo, D N Dellagiustina, E R Jawin, T Mccoy, P Michel, T Morota, M C Nolan, S R Schwartz, S Sugita, D S Lauretta

School of Earth & Environment Departmental Research

Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but …


National Parks Field Journal, Isadora Davis Jul 2024

National Parks Field Journal, Isadora Davis

Art and Design Student Scholarship and Projects

A handwritten, richly illustrated field journal by Binghamton University art major Isadora Davis, recording a trip through national parks in the American West via SUNY Broome's BIO 217: Ecology of National Parks. Davis uses colored pencil drawings and pressed botanical specimens to record landscapes, birds, mammals, and plant life in Grand Teton, Yellowstone, Wind Cave, and Badlands National Parks, as well as Custer State Park. Davis's sketches and diagrams visually explore how to decode past landscapes from current formations, while her written entries explain species diversity, animal behavior, and the mechanisms causing geological formations and geothermal events. Part memoir of …


Theoretical Semi-Quantitative Risk Assessment Methodology For Tunnel Design And Construction Processes, Ozgur Satici, Esra Satici Jul 2024

Theoretical Semi-Quantitative Risk Assessment Methodology For Tunnel Design And Construction Processes, Ozgur Satici, Esra Satici

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

All engineering projects involve risk management applications. Sometimes, risks cannot be effectively managed, leading to catastrophic consequences. Engineers must consciously or unconsciously manage these risks. Regardless of how risks are handled, project risks need to be systematically evaluated. Therefore, risk management procedures must be implemented in every project, particularly in geo-engineering projects, to mitigate undesirable consequences and achieve project objectives. However, the use of risk management procedures in underground excavation projects is not common. Numerous commonly employed underground excavation techniques lack assessment of risks, notably geotechnical risks. Most of them only evaluate rock structures and excavation stability in accordance with …


The Application Of Multi-Isotope Analysis To Assist In Geoprofiling Unidentified Decedents Within Florida, Liotta D. Noche-Dowdy Jun 2024

The Application Of Multi-Isotope Analysis To Assist In Geoprofiling Unidentified Decedents Within Florida, Liotta D. Noche-Dowdy

USF Tampa Graduate Theses and Dissertations

The biochemistry of human tissues can provide information for geoprofiling (geographic birthplace or migration patterns) of an unidentified decedent. Utilizing isotope analyses (both stable and radiogenic) from teeth, bone, nails, and/or hair reveals specific isotopic information that correlates to diverse geographic regions reflecting an individual’s birthplace and migration patterns. Isotope analysis of enamel and bone has been employed in bioarchaeology for decades to reconstruct the diet, health, and migration patterns of past populations. Isotope ratios measured from enamel can then be compared to isotope ratios measured from bone of the individual to track patterns of migration. The enamel from the …


Development Of Decision-Support Tools For Water Resources Management In Coupled Human-Natural Systems, Edgar J. Guerrón Orejuela Jun 2024

Development Of Decision-Support Tools For Water Resources Management In Coupled Human-Natural Systems, Edgar J. Guerrón Orejuela

USF Tampa Graduate Theses and Dissertations

Water is an indispensable resource for all forms of life. Water is a cornerstone for economic development, public health, and social well-being. However, increasing water demand and challenges posed by climate change, pollution, population growth, and land use change underscore the urgent need for effective water management strategies. To address these complexities and ensure the sustainable use of water resources, it is imperative to adopt science-based decision-support tools. These tools leverage data, models, and analytical techniques to provide valuable insights and recommendations that guide decision-makers in formulating evidence-based policies and practices.

Effective water management requires a comprehensive understanding of the …


Local Seismic Investigations In Arizona: Analysis Of A Low-To-Moderate-Magnitude Aftershock Sequence And A Pilot Study Of Monsoon-Driven Flash Floods, Kathryn Margo Dorn Jun 2024

Local Seismic Investigations In Arizona: Analysis Of A Low-To-Moderate-Magnitude Aftershock Sequence And A Pilot Study Of Monsoon-Driven Flash Floods, Kathryn Margo Dorn

USF Tampa Graduate Theses and Dissertations

Arizona encompasses a strikingly diverse array of geological terranes and physiographic terrain and consequently experiences a wide range of tectonic and meteorological phenomena, many of which generate distinctive seismic signals. For much of the past century, however, the state has largely lacked the style of dense seismic networks now prevalent in some regions of neighboring California, allowing myriad low-magnitude earthquakes and other subtle seismic sources to elude detection and characterization. In this dissertation, I utilize the high-resolution data of two temporary local seismic networks to investigate two such sources – the primarily low-magnitude but prolific aftershock sequence of the 29 …


Resolving Antarctic Margin Paleoceanography For Two Different Timescales And Archives, Theresa M. King Jun 2024

Resolving Antarctic Margin Paleoceanography For Two Different Timescales And Archives, Theresa M. King

USF Tampa Graduate Theses and Dissertations

Recent decades have seen increased rates of ice mass loss from Antarctic ice sheets, through thinning of many ice shelves around the periphery of the continent. The most vulnerable are the glacial systems that are marine-terminating and grounded below sea level, a characteristic that exposes these systems to sea level rise and warming oceans. Enhanced basal melting under the influence of warm ocean water masses can lead to thinning and retreat of glaciers, and ultimately to the acceleration of grounded ice loss. To contextualize current ice mass loss and contribute to accurate model projections for future retreat scenarios, it is …


Diversity And Evolution Of Nitric Oxide Reduction In Bacteria And Archaea, Ranjani Murali, Laura A. Pace, Robert A. Sanford, Luce M. Ward, Mackenzie M. Lynes, Roland Hatzenpichler, Usha F. Lingappa, Woodward W. Fischer, Robert B. Gennis, James Hemp Jun 2024

Diversity And Evolution Of Nitric Oxide Reduction In Bacteria And Archaea, Ranjani Murali, Laura A. Pace, Robert A. Sanford, Luce M. Ward, Mackenzie M. Lynes, Roland Hatzenpichler, Usha F. Lingappa, Woodward W. Fischer, Robert B. Gennis, James Hemp

Geosciences: Faculty Publications

With the advent of culture-independent techniques for studying environmental microbes, our knowledge of their diversity has exploded, uncovering unique organisms, pathways, and proteins carrying out important processes in the biosphere. Novel biochemical reactions are often proposed based on sequence data, but experimental validation is difficult and rare. In this work, we used environmental sequence data to find enzymes that produce the greenhouse gas N2O from NO and validated our hypothesis with experiments. These new enzymes likely contribute to global N2O fluxes and expand the breadth of nitrogen cycling. We also demonstrated that these enzymes evolved multiple …


Perspectives On Modifiable Spatiotemporal Unit Problems In Remote Sensing Of Agriculture: Evaluating Rice Production In Vietnam And Tools For Analysis, Brad G. Peter, Joseph P. Messina, Victoria Breeze, Cadi Y. Fung, Abhinav Kapoor, Peilei Fan Jun 2024

Perspectives On Modifiable Spatiotemporal Unit Problems In Remote Sensing Of Agriculture: Evaluating Rice Production In Vietnam And Tools For Analysis, Brad G. Peter, Joseph P. Messina, Victoria Breeze, Cadi Y. Fung, Abhinav Kapoor, Peilei Fan

Geosciences Faculty Publications and Presentations

Measuring agricultural productivity is a multiscale spatiotemporal problem that requires multiscale solutions. In Vietnam, rice comprises a substantial portion of the cultivated area and is a major export crop that supplies much of the global food system. Understanding the when and where of rice productivity is vital to addressing changes to yields and food security, yet descriptive summarizations will vary depending on the spatial or temporal scale of analysis. This paper explores rice trends across Vietnam over a 19-year period, giving specific attention to modifiable spatiotemporal unit problems by evaluating productivity across multiple time periods and administrative levels. A generalizable …


The Use Of Laja In Construction In Ancient Mesoamerica: A View From The Southern Gulf Lowlands Of Veracruz, Mexico, Lauren E. Smith Jun 2024

The Use Of Laja In Construction In Ancient Mesoamerica: A View From The Southern Gulf Lowlands Of Veracruz, Mexico, Lauren E. Smith

Steeplechase: An ORCA Student Journal

The archaeology of the southern Gulf lowlands of Veracruz, Mexico is notable for its research pertaining to the Olmec culture (Jaime-Riveron 2016; Loughlin 2012; Pool 2006). The region was home to the Colossal Olmec Heads: large, easily identifiable sculptures crafted from the volcanic rock of the Tuxtlas Volcanic Field. The use of volcanic resources in such grand presentations may instill a bias in the research of some archaeologists, but it is important to consider how these and other volcanic resources might have been used in everyday life (e.g., Jaime-Riveron 2016: 86). The consolidated volcanic ash in this region is referred …