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Articles 211 - 240 of 2467

Full-Text Articles in Earth Sciences

A Multidisciplinary Approach To Resolving The End-Guadalupian Extinction, Christopher R. Fielding, Scott E. Bryan, James L. Crowley, Tracy D. Frank, Michael T. Hren, Chris Mays, Stephen Mcloughlin, Jun Shen, Peter J. Wagner, Arne Winguth, Cornelia Winguth Dec 2023

A Multidisciplinary Approach To Resolving The End-Guadalupian Extinction, Christopher R. Fielding, Scott E. Bryan, James L. Crowley, Tracy D. Frank, Michael T. Hren, Chris Mays, Stephen Mcloughlin, Jun Shen, Peter J. Wagner, Arne Winguth, Cornelia Winguth

Geosciences Faculty Publications and Presentations

The transition from the middle to late Permian (Guadalupian–Lopingian) is claimed to record one or more extinction events that rival the ‘Big Five’ in terms of depletion of biological diversity and reorganization of ecosystem structure. Yet many questions remain as to whether the events recorded in separate regions were synchronous, causally related, or were of a magnitude rivaling other major crises in Earth's history. In this paper, we survey some major unresolved issues related to the Guadalupian–Lopingian transition and offer a multidisciplinary approach to advance understanding of this under-appreciated biotic crisis by utilizing records in Southern Hemisphere high-palaeolatitude settings. We …


A Survey Of Non-Usgs Continuous Streamflow Gaging Networks In The Pacific Northwest, Kendra E. Kaiser, Kyle Blasch, Mcallister Hall Dec 2023

A Survey Of Non-Usgs Continuous Streamflow Gaging Networks In The Pacific Northwest, Kendra E. Kaiser, Kyle Blasch, Mcallister Hall

Geosciences Faculty Publications and Presentations

Extensive streamflow data sources exist beyond the largest streamflow data provider in the United States, the U.S. Geological Survey. We developed and distributed a survey to about 300 individuals and organizations that collect streamflow data across the Pacific Northwest (Idaho, Oregon, Washington). We received 100 responses with 56% of those sufficiently complete to include in the analysis. From these responses, there are about 2000 streamflow monitoring locations in the region beyond the USGS monitoring network. The duration of record for gages is related to the size of the streamflow gaging network, with small and large networks generally operating monitoring locations …


The Surface Atmosphere Integrated Field Laboratory (Sail) Campaign, D. R. Feldman, A. C. Aiken, W. R. Boos, R. W. H. Carroll, V. Chandrasekar, S. Collis, J. M. Creamean, G. De Boer, J. Deems, P. J. Demott, J. Fan, A. N. Flores, D. Gochis, M. Grover, T. C. J. Hill, A. Hodshire, E. Hulm, C. C. Hume, R. Jackson, F. Junyent, A. Kennedy, M. Kumjian, E. J. T. Levin, J. D. Lundquist, J. O'Brien, M. S. Raleigh, J. Reithel, A. Rhoades, K. Rittger, W. Rudisill, Z. Sherman, E. Siirila-Woodburn, S. M. Skiles, J. N. Smith, R. C. Sullivan, A. Theisen, M. Tuftedal, A. C. Varble, A. Wiedlea, S. Wielandt, K. Williams, Z. Xu Dec 2023

The Surface Atmosphere Integrated Field Laboratory (Sail) Campaign, D. R. Feldman, A. C. Aiken, W. R. Boos, R. W. H. Carroll, V. Chandrasekar, S. Collis, J. M. Creamean, G. De Boer, J. Deems, P. J. Demott, J. Fan, A. N. Flores, D. Gochis, M. Grover, T. C. J. Hill, A. Hodshire, E. Hulm, C. C. Hume, R. Jackson, F. Junyent, A. Kennedy, M. Kumjian, E. J. T. Levin, J. D. Lundquist, J. O'Brien, M. S. Raleigh, J. Reithel, A. Rhoades, K. Rittger, W. Rudisill, Z. Sherman, E. Siirila-Woodburn, S. M. Skiles, J. N. Smith, R. C. Sullivan, A. Theisen, M. Tuftedal, A. C. Varble, A. Wiedlea, S. Wielandt, K. Williams, Z. Xu

Geosciences Faculty Publications and Presentations

The science of mountainous hydrology spans the atmosphere through the bedrock and inherently crosses physical and disciplinary boundaries: land–atmosphere interactions in complex terrain enhance clouds and precipitation, while watersheds retain and release water over a large range of spatial and temporal scales. Limited observations in complex terrain challenge efforts to improve predictive models of the hydrology in the face of rapid changes. The Upper Colorado River exemplifies these challenges, especially with ongoing mismatches between precipitation, snowpack, and discharge. Consequently, the U.S. Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) user facility has deployed an observatory to the East River Watershed …


Uas-Based Quantification Of Dynamic Lahar Channel Morphology At Volcán De Fuego, Guatemala, Jerry Clay Mock Dec 2023

Uas-Based Quantification Of Dynamic Lahar Channel Morphology At Volcán De Fuego, Guatemala, Jerry Clay Mock

Boise State University Theses and Dissertations

Lahars are responsible for 26% of the deaths associated with volcanic activity reported since 1500 AD, and are extremely destructive to infrastructure (Thouret et al., 2020). Secondary lahars are volcanic mudflows commonly triggered by rainfall. Valuable land and buildings may be covered or destroyed by thick deposits including heavy boulders, mud, and debris. Bridges and roads can be washed out, cutting people off from vital services and potentially placing them in danger from other hazards. Volcán de Fuego in Guatemala actively produces pyroclastic material in small Strombolian eruptions every 15-20 minutes. Fuego occasionally has larger eruptions and has produced over …


Examining The Spatial Periodicity Of Force Chains And Strain Localization In Polycrystal Models, Richard D. Panduro-Allanson Dec 2023

Examining The Spatial Periodicity Of Force Chains And Strain Localization In Polycrystal Models, Richard D. Panduro-Allanson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shear strain localization is typical in deforming rocks and is vital for developing faults and tectonic boundaries. There are various proposed drivers of shear localization (temperature, fluid, phase transformation, and microstructure); we will explore the effects of elastic heterogeneity (a microstructural influence) on shear localization in polycrystal models. Elastic heterogeneity can lead to varied stress states in material and drive shear localization. Previous simulations of elastically heterogeneous polycrystal models have shown that the stress distribution can be described as forming an anastomosing pattern of high-stress streams parallel to the compression direction. This anastomosing patterning resembles force chains; linear, high-stress features …


Modeling The Peak Ground Acceleration And Assessing The Economic Loss And Casualty Due To Potential Earthquakes Of Various Magnitudes In The New Madrid Seismic Zone, Mahmud Afroz Dec 2023

Modeling The Peak Ground Acceleration And Assessing The Economic Loss And Casualty Due To Potential Earthquakes Of Various Magnitudes In The New Madrid Seismic Zone, Mahmud Afroz

Graduate Theses and Dissertations

The New Madrid Seismic Zone (NMSZ) is one of the active tectonic zones capable of producing big earthquakes in the southcentral USA. The objective of this study was to assess the economic losses and casualties that might be caused by various magnitudes of seismic events in the NMSZ. The manifestation is the estimation for each magnitude which is using the Peak Ground Acceleration (PGA) that might occur during an earthquake. It is calculated using an attenuation function that correlates the intensity of local ground movement, the earthquake magnitude, and the distance from its epicenter. The assessment of casualties was conducted …


Electrofacies Analysis Using A Geostatistical Approach, Northern Iraq Case Study, Hussein S. Hussein Nov 2023

Electrofacies Analysis Using A Geostatistical Approach, Northern Iraq Case Study, Hussein S. Hussein

Polytechnic Journal

The distribution of petrophysical parameters is governed by lithology, hence understanding the spatial variation in lithology is essential for reservoir characterisation. This study points out the use of well logs to estimate the lithology of carbonate rocks (limestone, marly limestone, dolomite, and dolomitic limestone) found in Upper Cretaceous to Miocene formations at the Khabbaz Oil Field in Northern Iraq. Applying the multivariate regression technique to neutron, and density data enabled accurate lithology prediction. By using independent values (well log data) to predict a dependent value (lithology), this technique is a progression of regression analysis. The formations under study comprised a …


Evaluating 3 Decades Of Precipitation In The Upper Colorado River Basin From A High-Resolution Regional Climate Model, William Rudisill, Alejandro Flores, Rosemary Carroll Nov 2023

Evaluating 3 Decades Of Precipitation In The Upper Colorado River Basin From A High-Resolution Regional Climate Model, William Rudisill, Alejandro Flores, Rosemary Carroll

Geosciences Faculty Publications and Presentations

Convection-permitting regional climate models (RCMs) have recently become tractable for applications at multi-decadal timescales. These types of models have tremendous utility for water resource studies, but better characterization of precipitation biases is needed, particularly for water-resource-critical mountain regions, where precipitation is highly variable in space, observations are sparse, and the societal water need is great. This study examines 34 years (1987–2020) of RCM precipitation from the Weather Research and Forecasting model (WRF; v3.8.1), using the Climate Forecast System Reanalysis (CFS; CFSv2) initial and lateral boundary conditions and a 1 km × 1 km innermost grid spacing. The RCM is centered …


U–Pb Zircon Ages, Mapping, And Biostratigraphy Of The Payette Formation And Idaho Group North Of The Western Snake River Plain, Idaho: Implications For Hydrocarbon System Correlation, Renee L. Love, Reed S. Lewis, Spencer H. Wood, Dennis M. Feeney, Mark D. Schmitz Nov 2023

U–Pb Zircon Ages, Mapping, And Biostratigraphy Of The Payette Formation And Idaho Group North Of The Western Snake River Plain, Idaho: Implications For Hydrocarbon System Correlation, Renee L. Love, Reed S. Lewis, Spencer H. Wood, Dennis M. Feeney, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

Sedimentary deposits north of the western Snake River Plain host Idaho’s first and only producing oil and gas field. They consist of the lower to middle Miocene Payette Formation, the middle to upper Miocene Poison Creek and Chalk Hills Formations, and the Pliocene to lower Pleistocene Glenns Ferry Formation. Using new geochronology, palynomorph biostratigraphy, and geologic mapping, we connect updip surface features to subsurface petroleum play elements. The Payette Formation is a likely main source of the hydrocarbons, and acts as one of the reservoirs in the unnamed basin. Here, we redefine the Payette Formation as 0 to ~3,500 ft …


Astronomical And Tectonic Influences On Climate And Deposition Revealed Through Radioisotopic Geochronology And Bayesian Age-Depth Modeling Of The Early Eocene Green River Formation, Wyoming, Usa, Benjamin T. Bruck, Brad S. Singer, Mark D. Schmitz, Alan R. Carroll, Stephen Meyers, Andrew P. Walters, Brian R. Jicha Nov 2023

Astronomical And Tectonic Influences On Climate And Deposition Revealed Through Radioisotopic Geochronology And Bayesian Age-Depth Modeling Of The Early Eocene Green River Formation, Wyoming, Usa, Benjamin T. Bruck, Brad S. Singer, Mark D. Schmitz, Alan R. Carroll, Stephen Meyers, Andrew P. Walters, Brian R. Jicha

Geosciences Faculty Publications and Presentations

The Wilkins Peak Member (WPM) of the Green River Formation in Wyoming, USA, comprises alternating lacustrine and alluvial strata that preserve a record of terrestrial climate during the early Eocene climatic optimum. We use a Bayesian framework to develop age-depth models for three sites, based on new 40Ar/39Ar sanidine and 206Pb/238U zircon ages from seven tuffs. The new models provide two- to ten-fold increases in temporal resolution compared to previous radioisotopic age models, confirming eccentricity-scale pacing of WPM facies, and permitting their direct comparison to astronomical solutions. Starting at ca. 51 Ma, the median …


Groundwater System Characterisation: Fortescue Alluvial Fan, Michael J. Donn, Olga V. Barron, Axel Suckow, Chris Turnadge, John A. Simons, Robert J. Paul, Christopher Schelfhout Dr Nov 2023

Groundwater System Characterisation: Fortescue Alluvial Fan, Michael J. Donn, Olga V. Barron, Axel Suckow, Chris Turnadge, John A. Simons, Robert J. Paul, Christopher Schelfhout Dr

Natural resources commissioned reports

This report focuses on groundwater system characterisation in the region north of Newman, based on analysis of pre-existing data and data newly acquired during project activities. Groundwater system characterisation was an important research component supporting the assessment of managed aquifer recharge opportunities, using mine dewatering surplus generated (due to mining below the watertable) at large BHP Billiton Iron Ore operations in the eastern Pilbara mining zone, and aiming to support irrigated agriculture. The assessment area is located north of Ethel Gorge and covers the Upper Fortescue River floodplain and surroundings. The project added much knowledge to this largely ‘data-poor’ region, …


Reducing Uncertainty In Sea-Level Rise Prediction: A Spatial-Variability-Aware Approach, Subhankar Ghosh, Shuai An, Arun Sharma, Jayant Gupta, Shashi Shekhar, Aneesh Subramanian Oct 2023

Reducing Uncertainty In Sea-Level Rise Prediction: A Spatial-Variability-Aware Approach, Subhankar Ghosh, Shuai An, Arun Sharma, Jayant Gupta, Shashi Shekhar, Aneesh Subramanian

I-GUIDE Forum

Given multi-model ensemble climate projections, the goal is to accurately and reliably predict future sea-level rise while lowering the uncertainty. This problem is important because sea-level rise affects millions of people in coastal communities and beyond due to climate change's impacts on polar ice sheets and the ocean. This problem is challenging due to spatial variability and unknowns such as possible tipping points (e.g., collapse of Greenland or West Antarctic ice-shelf), climate feedback loops (e.g., clouds, permafrost thawing), future policy decisions, and human actions. Most existing climate modeling approaches use the same set of weights globally, during either regression or …


Snowpack Relative Permittivity And Density Derived From Near-Coincident Lidar And Ground-Penetrating Radar, Randall Bonnell, Daniel Mcgrath, Andrew R. Hedrick, Ernesto Trujillo, Tate G. Meehan, Keith Williams, Hans-Peter Marshall, Graham Sexstone, John Fulton, Michael J. Ronayne, Steven R. Fassnacht, Ryan Webb, Katherine E. Hale Oct 2023

Snowpack Relative Permittivity And Density Derived From Near-Coincident Lidar And Ground-Penetrating Radar, Randall Bonnell, Daniel Mcgrath, Andrew R. Hedrick, Ernesto Trujillo, Tate G. Meehan, Keith Williams, Hans-Peter Marshall, Graham Sexstone, John Fulton, Michael J. Ronayne, Steven R. Fassnacht, Ryan Webb, Katherine E. Hale

Geosciences Faculty Publications and Presentations

Depth-based and radar-based remote sensing methods (e.g., lidar, synthetic aperture radar) are promising approaches for remotely measuring snow water equivalent (SWE) at high spatial resolution. These approaches require snow density estimates, obtained from in-situ measurements or density models, to calculate SWE. However, in-situ measurements are operationally limited, and few density models have seen extensive evaluation. Here, we combine near-coincident, lidar-measured snow depths with ground-penetrating radar (GPR) two-way travel times (twt) of snowpack thickness to derive >20 km of relative permittivity estimates from nine dry and two wet snow surveys at Grand Mesa, Cameron Pass, and Ranch Creek, Colorado. …


Early Ordovician Seamounts Preserved In The Canadian Cordillera: Implications For The Rift History Of Western Laurentia, Rose N. Cobbett, Luke P. Beranek, Stephen J. Piercey, James L. Crowley, Maurice Colpron Oct 2023

Early Ordovician Seamounts Preserved In The Canadian Cordillera: Implications For The Rift History Of Western Laurentia, Rose N. Cobbett, Luke P. Beranek, Stephen J. Piercey, James L. Crowley, Maurice Colpron

Geosciences Faculty Publications and Presentations

The breakup of the supercontinent Rodinia and development of the western Laurentian rifted margin are in part recorded by Neoproterozoic to mid-Paleozoic igneous and sedimentary rock successions in the Canadian Cordillera. New bedrock mapping and volcanic facies analysis of Early Ordovician mafic rocks assigned to the Menzie Creek Formation in central Yukon allow reconstruction of the depositional environment during the volcanic eruptions, whole-rock geochemical data constrain the melting depth and crust-mantle source regions of the igneous rocks within the study area, and zircon U-Pb age studies provide determination of the precise timing of submarine eruptions. Menzie Creek Formation volcanic rocks …


Assessing Controls On Ice Dynamics At Crane Glacier, Antarctic Peninsula, Using A Numerical Ice Flow Model, Rainey Aberle, Ellyn M. Enderlin, Hans-Peter Marshall, Michal Kopera, Tate G. Meehan Oct 2023

Assessing Controls On Ice Dynamics At Crane Glacier, Antarctic Peninsula, Using A Numerical Ice Flow Model, Rainey Aberle, Ellyn M. Enderlin, Hans-Peter Marshall, Michal Kopera, Tate G. Meehan

Geosciences Faculty Publications and Presentations

The Antarctic Peninsula's widespread glacier retreat and ice shelf collapse have been attributed to atmospheric and oceanic warming. Following the initial post-collapse period of retreat, several former tributary glaciers of the Larsen A and B ice shelves have been slowly re-advancing for more than a decade. Here, we use a flowline model of Crane Glacier to gauge the sensitivity of former tributary glaciers to future climate change following this period of long-term dynamic adjustment. The glacier's long-term geometry and speed changes are similar to those of other former Larsen A and B tributaries, suggesting that Crane Glacier is a reasonable …


Construction Aspects And Seismic Analysis Of Typical Buildings In Dolpo, Lhakpa Tsering Oct 2023

Construction Aspects And Seismic Analysis Of Typical Buildings In Dolpo, Lhakpa Tsering

Independent Study Project (ISP) Collection

This study delves into the construction aspects and seismic analysis of typical buildings in the challenging terrain of Dolpo, situated within the Himalayan mountain range. Dolpo's unique geological and geographical characteristics, combined with its susceptibility to seismic activity, make it crucial to investigate and understand the dynamics of construction in this remote region. The research explores traditional and contemporary building practices, aiming to elucidate the interplay between construction methodologies and seismic resilience. Through a comprehensive examination of the geological context, structural design, and seismic vulnerability, this study contributes valuable insights to inform the development of robust and earthquake-resistant building strategies …


The Influence Of Volcano Topographic Changes On Infrasound Amplitude: Lava Fountains At Mt. Etna In 2021, Adriana Iozzia, Leighton M. Watson, Massimo Cantarero, Emanuela De Beni, Giuseppe Di Grazia, Gaetana Ganci, Jeffrey B. Johnson, Eugenio Privitera, Cristina Proietti, Mariangela Sciotto, Andrea Cannata Oct 2023

The Influence Of Volcano Topographic Changes On Infrasound Amplitude: Lava Fountains At Mt. Etna In 2021, Adriana Iozzia, Leighton M. Watson, Massimo Cantarero, Emanuela De Beni, Giuseppe Di Grazia, Gaetana Ganci, Jeffrey B. Johnson, Eugenio Privitera, Cristina Proietti, Mariangela Sciotto, Andrea Cannata

Geosciences Faculty Publications and Presentations

Infrasound signals are used to investigate and monitor active volcanoes during eruptive and degassing activity. Infrasound amplitude information has been used to estimate eruptive parameters such as plume height, magma discharge rate, and lava fountain height. Active volcanoes are characterized by pronounced topography and, during eruptive activity, the topography can change rapidly, affecting the observed infrasound amplitudes. While the interaction of infrasonic signals with topography has been widely investigated over the past decade, there has been limited work on the impact of changing topography on the infrasonic amplitudes. In this work, the infrasonic signals accompanying 57 lava fountain paroxysms at …


Seabed Reflection Coefficient Variability In The Mono Lake Using Seismic Reflection Sparker Data, Francis Nnamdi Okeifufe Oct 2023

Seabed Reflection Coefficient Variability In The Mono Lake Using Seismic Reflection Sparker Data, Francis Nnamdi Okeifufe

Earth Sciences Theses and Dissertations

Acoustic reflections from a lakebed provide valuable information about the dynamic boundary between water and the lakebed, where sediments and biota in the water column eventually settle. In this study, we present a comprehensive analysis of reflected sound wave amplitudes to gain insights into the physical properties of a water-sediment boundary. We decided to carry out this analysis within the unique ecosystem of the Mono Lake basin due to the fact that the Mono Lake, a meromictic and hypersaline waterbody is situated within one of the most active yet understudied volcanic regions in the United States. The fact that the …


Geophysical Survey In Central North Dakota, University Of North Dakota. Energy And Environmental Research Center Oct 2023

Geophysical Survey In Central North Dakota, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about a 2023–2024 Energy & Environmental Research Center (EERC) geophysical survey in central North Dakota to evaluate the feasibility of developing safe and permanent CO2 storage in the project area. Describes the purpose of the survey and potential impact on local landowners.


An Effective Model For Dynamic Properties Of Local Soils And Their Influence On Seismic Response Of A Typical Reinforced Concrete Building, Kaveh Zehtab Oct 2023

An Effective Model For Dynamic Properties Of Local Soils And Their Influence On Seismic Response Of A Typical Reinforced Concrete Building, Kaveh Zehtab

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents an effective model to determine the dynamic properties of local soils and their impact on the seismic response of a typical mid-height reinforced concrete building. The results of the study suggest that the use of global models and empirical relationships for the dynamic properties of soils may not consider the effects of unique stress conditions on the cyclic response of the foundation soil. The study also investigates the seismic response of a site in central Adapazarı, Turkey, where four- to seven-story buildings suffered significant damage during the 1999 Kocaeli earthquake. A new model is presented that combines …


Application Of Model-Based Time Series Prediction Of Infrared Long-Wave Radiation Data For Exploring The Precursory Patterns Associated With The 2021 Madoi Earthquake, Jingye Zhang, Ke Sun, Junqing Zhu, Ning Mao, Dimitar Ouzounov Sep 2023

Application Of Model-Based Time Series Prediction Of Infrared Long-Wave Radiation Data For Exploring The Precursory Patterns Associated With The 2021 Madoi Earthquake, Jingye Zhang, Ke Sun, Junqing Zhu, Ning Mao, Dimitar Ouzounov

Mathematics, Physics, and Computer Science Faculty Articles and Research

Taking the Madoi MS 7.4 earthquake of 21 May 2021 as an example, this paper proposes using time series prediction models to predict the outgoing long-wave radiation (OLR) anomalies and study short-term pre-earthquake signals. Five time series prediction models, including autoregressive integrated moving average (ARIMA) and long short-term memory (LSTM), were trained with the OLR time series data of the aseismic moments in the 5° × 5° spatial range around the epicenter. The model with the highest prediction accuracy was selected to retrospectively predict the OLR values during the aseismic period and before the earthquake in the area. It …


Archean (3.3 Ga) Paleosols And Paleoenvironments Of Western Australia, Gregory J. Retallack, Mark D. Schmitz Sep 2023

Archean (3.3 Ga) Paleosols And Paleoenvironments Of Western Australia, Gregory J. Retallack, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

The Pilbara craton of northwestern Australia is known for what were, when reported, the oldest known microfossils and paleosols on Earth. Both interpretations are mired in controversy, and neither remain the oldest known. Both the microfossils and the paleosols have been considered hydrothermal artefacts: carbon films of vents and a large hydrothermal cupola, respectively. This study resampled and analyzed putative paleosols within and below the Strelley Pool Formation (3.3 Ga), at four classic locations: Strelley Pool, Steer Ridge, Trendall Ridge, and Streckfuss, and also at newly discovered outcrops near Marble Bar. The same sequence of sedimentary facies and paleosols was …


Two New Absolute Gravity Base Stations Established In Lincoln, Ne, Kris Guthrie, Irina Filina Sep 2023

Two New Absolute Gravity Base Stations Established In Lincoln, Ne, Kris Guthrie, Irina Filina

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Two new absolute gravity base stations were established on the University of Nebraska-Lincoln City Campus in April 2022. The values were transferred with a relative gravity meter from four existing stations within 238 miles and were later validated by the National Oceanic and Atmospheric Administration. The final values at 22.5 cm above marker height are 980177.781 ± 0.010 mGal at the Lincoln Bell Tower Station and 980178.079 ± 0.010 mGal at the Lincoln Museum station with a gravity gradient of -3.105 µGal/cm. This paper describes the process of transferring gravity values and outlines recommendations for similar projects in the future.


Constraints On Near-Ridge Magmatism Using 40Ar/39Ar Geochronology Of Enriched Morb From The 8°20' N Seamount Chain, Molly K. Anderson, Michael R. Perfit, Leah E. Morgan, Daniel J. Fornari, Michael Cosca, V. Dorsey Wanless Sep 2023

Constraints On Near-Ridge Magmatism Using 40Ar/39Ar Geochronology Of Enriched Morb From The 8°20' N Seamount Chain, Molly K. Anderson, Michael R. Perfit, Leah E. Morgan, Daniel J. Fornari, Michael Cosca, V. Dorsey Wanless

Geosciences Faculty Publications and Presentations

Our understanding of the spatial-temporal-compositional relationships between off-axis magmatism and mid-ocean ridge spreading centers is limited. Determining the 40Ar/39Ar ages of mid-ocean ridge basalt (MORB) lavas erupting near mid-ocean ridges (MOR) has been a challenge due to the characteristically low K2O contents in incompatible element-depleted normal MORB (NMORB). High-precision 40Ar/39Ar geochronology is used here to determine ages of young, basaltic lavas erupted along the 8°20' N seamount chain west of the East Pacific Rise (EPR) axis that have a range of incompatible element enrichments (EMORB) suitable for 40Ar/39Ar geochronology …


Is Macroporosity Controlled By Complexed Clay And Soil Organic Carbon?, Aaron N. Koop, Daniel R. Hirmas, Sharon A. Billings, Li Li, Alejandro Cueva, Xi Zhang, Hang Wen, Attila Nemes, Lígia F. T. Souza, Hoori Ajami, Alejandro N. Flores, Aoesta K. Rudick, Annalise Guthrie, Lola M. Klamm, Micah Unruh, Pamela L. Sullivan Sep 2023

Is Macroporosity Controlled By Complexed Clay And Soil Organic Carbon?, Aaron N. Koop, Daniel R. Hirmas, Sharon A. Billings, Li Li, Alejandro Cueva, Xi Zhang, Hang Wen, Attila Nemes, Lígia F. T. Souza, Hoori Ajami, Alejandro N. Flores, Aoesta K. Rudick, Annalise Guthrie, Lola M. Klamm, Micah Unruh, Pamela L. Sullivan

Geosciences Faculty Publications and Presentations

Multi-scale evidence of rapid, climate-induced soil structural changes occurring at yearly to decadal timescales is mounting. As a result, it has become increasingly important to identify the properties and mechanisms controlling the development and maintenance of soil structure and associated macroporosity. This is especially relevant since macroporosity has disproportionate effects on saturated hydraulic conductivity (Ksat) which strongly influences water storage and flux, thus, affecting the water cycle. In this study, we use decision trees and piecewise linear regression to assess the influence of soil and climate properties on effective porosity (EP; a proxy of macroporosity) in both …


U-Pb Zircon Dates From North American And British Avalonia Bracket The Lower–Middle Cambrian Boundary Interval, With Evaluation Of The Miaolingian Series As A Global Unit, Ed Landing, Mark D. Schmitz, Stephen R. Westrop, Gerd Geyer Sep 2023

U-Pb Zircon Dates From North American And British Avalonia Bracket The Lower–Middle Cambrian Boundary Interval, With Evaluation Of The Miaolingian Series As A Global Unit, Ed Landing, Mark D. Schmitz, Stephen R. Westrop, Gerd Geyer

Geosciences Faculty Publications and Presentations

High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma (Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma (Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma (Kiskinella cristata Zone) and 506.25 ± 0.07 Ma (Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 …


Applications Of Observational Seismology: Insights Into Volcanic And Near Surface Processes, Justin T. Wilgus Aug 2023

Applications Of Observational Seismology: Insights Into Volcanic And Near Surface Processes, Justin T. Wilgus

Earth and Planetary Sciences ETDs

The field of observational seismology has made tremendous progress in the past two decades. This progress has been multi-faceted in form, but significant contributions emanated from 1) increases in both the quality and the quantity of seismic data 2) advances in computational power 3) advances in algorithmic capability, including machine learning. In this dissertation I report on three distinctly different seismic applications made possible by the aforementioned progress and discuss the insights these applications have provided in understanding volcanic and near surface processes of the Earth.

In the first chapter titled, “Shear Velocity Evidence of Upper Crustal Magma Storage Beneath …


Detection And Identification Of Pre-Seismic Thermal Anomalies In Cloudy Conditions Associated With The 2022 Luding (China) Mw 6.6 Earthquake, Feng Jing, Meng Jiang, Lu Zhang, Ramesh P. Singh Aug 2023

Detection And Identification Of Pre-Seismic Thermal Anomalies In Cloudy Conditions Associated With The 2022 Luding (China) Mw 6.6 Earthquake, Feng Jing, Meng Jiang, Lu Zhang, Ramesh P. Singh

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Over the past three decades, thermal anomalies from satellite infrared data have been widely discussed and associated with earthquakes. Besides infrared satellite data, the recent use of passive microwave satellite data has emerged as an important dataset to detect the potential thermal anomalies prior to earthquakes in all weather conditions due to its capability to monitor the earth in cloudy and foggy conditions and has been applied to the numerous strong earthquake events around the world. On 5 September 2022, an Mw 6.6 earthquake occurred in Luding county, nearby Mt. Gongga, China, with heavy cloud coverage over the epicenter and …


The Temporal Evolution Of Subduction Initiation In The Samail Ophiolite: High-Precision U–Pb Zircon Petrochronology Of The Metamorphic Sole, Matthew Rioux, Joshua M. Garber, Michael Searle, James L. Crowley, Sally Stevens, Mark Schmitz, Andrew Kylander-Clark, Kayla Leal, Tyler Ambrose, Andrew J. Smye Aug 2023

The Temporal Evolution Of Subduction Initiation In The Samail Ophiolite: High-Precision U–Pb Zircon Petrochronology Of The Metamorphic Sole, Matthew Rioux, Joshua M. Garber, Michael Searle, James L. Crowley, Sally Stevens, Mark Schmitz, Andrew Kylander-Clark, Kayla Leal, Tyler Ambrose, Andrew J. Smye

Geosciences Faculty Publications and Presentations

High-precision dating of the metamorphic sole of ophiolites can provide insight into the tectonic evolution of ophiolites and subduction zone processes. To understand subduction initiation beneath a young, well-preserved and well-characterized ophiolite, we performed coupled zircon laser-ablation inductively coupled mass spectrometry trace element analyses and high-precision isotope dilution-thermal ionization mass spectrometry U–Pb dating on 25 samples from the metamorphic sole of the Samail ophiolite (Oman-United Arab Emirates). Zircon grains from amphibolite- to granulite-facies (0.8–1.3 GPa, ~700–900°C), garnet- and clinopyroxene-bearing amphibolite samples (n = 18) show systematic trends of decreasing heavy rare earth element slope (HREE; Yb/Dy) with decreasing Yb …


Uav-Based Quantification Of Dynamic Lahar Channel Morphology At Volcán De Fuego, Guatemala, Jerry C. Mock, Jeffrey B. Johnson, Armando Pineda, Gustavo Bejar, Amilcar Roca Aug 2023

Uav-Based Quantification Of Dynamic Lahar Channel Morphology At Volcán De Fuego, Guatemala, Jerry C. Mock, Jeffrey B. Johnson, Armando Pineda, Gustavo Bejar, Amilcar Roca

Geosciences Faculty Publications and Presentations

This study quantified erosional and depositional processes for secondary lahars in Las Lajas drainage at Volcán de Fuego, Guatemala, during the rainy season from May to October 2021. Abundant pyroclastic material from ongoing eruptive activity is remobilized seasonally during heavy precipitation, which can impact infrastructure and populations living near Fuego. Our region of focus was in an agricultural zone 6 to 10 km from the summit, surveyed with an unoccupied aerial vehicle (UAV) quadcopter at monthly intervals. Imagery was processed into overlapping time-lapse structure from motion digital elevation models (DEMs). DEMs were differenced to find volumetric changes as a function …