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2021

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Articles 211 - 240 of 16206

Full-Text Articles in Earth Sciences

Iron Geochemistry Across An Estuary-To-Coastal Gradient, Lissett G. Diaz Dec 2021

Iron Geochemistry Across An Estuary-To-Coastal Gradient, Lissett G. Diaz

Honors Theses

Iron is a ubiquitous earth element that participates in biogeochemical processes that occur in marine sediments. Microorganisms utilize iron for many purposes, including cell growth, conserving energy, and for maintaining metabolic activity. In coastal sedimentary settings, understanding the redox reactions involving ferric iron, Fe3+, and ferrous iron, Fe2+, in its solid phase and pore-water phases, respectively, enable an appreciation of biogeochemical transformations occurring in the coastal zone. In this study, iron concentrations in sediment of ranging permeability were determined at four stations marking an estuary-coast transition zone in Singleton Swash in Myrtle Beach, South Carolina. The …


Understanding Students’ Global Interdependence In Science Instruction, Walter S. Smith Dec 2021

Understanding Students’ Global Interdependence In Science Instruction, Walter S. Smith

Journal of Global Education and Research

Multiple American educational organizations such as the National Education Association, Association for Supervision and Curriculum Development, and the Council of Chief State School Officers have advocated for globalizing the K-12 curriculum. The National Science Teaching Association (NSTA) in a position statement on international education and the Next Generation Science Standards have produced goals and standards for internationalizing the science curriculum by addressing topics such as climate change, environment, and disease that cross borders. In contrast to those pronouncements on the curriculum, this article views global science education through an instructional lens that focuses on a students’ global interdependence in science …


Soil Structure And Soil Moisture Dynamics Inferred From Time-Lapse Electrical Resistivity Tomography, Travis Nielson, John Bradford, Jen Pierce, Mark Seyfried Dec 2021

Soil Structure And Soil Moisture Dynamics Inferred From Time-Lapse Electrical Resistivity Tomography, Travis Nielson, John Bradford, Jen Pierce, Mark Seyfried

Geosciences Faculty Publications and Presentations

The semi-arid sagebrush steppe in the western United States faces pressures from the agriculture industry, recreation use, invasive grasses, and a changing climate. A key to facilitating the healthy management of this ecosystem is understanding the distribution and behavior of soil moisture in the vadose zone in both natural and agricultural settings. Within unsaturated environments, soil moisture is spatially and temporally heterogeneous, and changes in porosity and permeability within arid soils complicate characterization of soil hydrologic properties. Importantly, accumulations of ‘caliche’ or pedogenic calcium carbonate in arid soils can greatly limit permeability; however, observing the role that caliche plays in …


Quantifying Surface Water Capture By Municipal Pumping Wells In An Urban Watershed Impacted By Road Salt, Austen York Dec 2021

Quantifying Surface Water Capture By Municipal Pumping Wells In An Urban Watershed Impacted By Road Salt, Austen York

Masters Theses

The Spring Valley sub-watershed is located within the Kalamazoo Township contains Spring Valley Lake, a man-made impoundment that ultimately discharges into the Kalamazoo River. Elevated chloride levels in pumped water from the Kalamazoo Station 14 municipal wellfield, located along the shoreline of Spring Valley Lake, has resulted in less than ideal corrosivity values for the water distribution system. Specific project objectives include: (1) identifying the cause of elevated chloride, (2) assessing surface water capture by the Station 14 wellfield, and (3) characterizing of water quality in Spring Valley Lake. Monitoring along a series of sampling transects spanning the sub-watershed, focused …


Chronostratigrapy Of Miocene Fluviolacustrine Deposits In Amargosa Valley, Levente Laisz Dec 2021

Chronostratigrapy Of Miocene Fluviolacustrine Deposits In Amargosa Valley, Levente Laisz

Loma Linda University Electronic Theses, Dissertations & Projects

Fluviolacustrine deposits of middle Miocene age occur on the western margins of the Amargosa Valley, in the central Basin and Range. These deposits contain the earliest pupfish (Cyprinodon) reported from the fossil record. National Park collections contain specimens of pupfish fossils, interpreted as possibly Pliocene; however the exact collection location and stratigraphic horizon was not known. Therefore, the geographic extent of the fossil locality and geologic age of these specimens were uncertain. Recently, these collection sites were relocated and additional sites were discovered. Ar-Ar dating of interbedded tuffs established the first appearance datum of pupfish at 14.79 Ma and extended …


College Of Natural Sciences Newsletter, December 2021, College Of Natural Sciences Dec 2021

College Of Natural Sciences Newsletter, December 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 2, Issue 12

Page 1 Dean's Message
Page 2 Awards & Recognition
Page 2 Media Coverage of CNS
Page 3 Media Coverage Cont.
Page 4 Science as Art Competition
Page 5 Open PRAIRIE Data
Page 5 Grants Awarded in CNS


A Tighter Constraint On Earth-System Sensitivity From Long-Term Temperature And Carbon-Cycle Observations, Tony E. Wong, Ying Cui, Dana L. Royer, Klaus Keller Dec 2021

A Tighter Constraint On Earth-System Sensitivity From Long-Term Temperature And Carbon-Cycle Observations, Tony E. Wong, Ying Cui, Dana L. Royer, Klaus Keller

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The long-term temperature response to a given change in CO2 forcing, or Earth-system sensitivity (ESS), is a key parameter quantifying our understanding about the relationship between changes in Earth’s radiative forcing and the resulting long-term Earth-system response. Current ESS estimates are subject to sizable uncertainties. Long-term carbon cycle models can provide a useful avenue to constrain ESS, but previous efforts either use rather informal statistical approaches or focus on discrete paleoevents. Here, we improve on previous ESS estimates by using a Bayesian approach to fuse deep-time CO2 and temperature data over the last 420 Myrs with a long-term carbon cycle …


Cover Crop Effects On Near-Surface Soil Aggregate Stability In The Southern Mississippi Valley Loess (Mlra 134), Chandler M. Arel Dec 2021

Cover Crop Effects On Near-Surface Soil Aggregate Stability In The Southern Mississippi Valley Loess (Mlra 134), Chandler M. Arel

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Intensive agricultural cultivation within major land resource area (MLRA) 134, the Southern Mississippi Valley Loess, has led to soil erosion, soil compaction, and the overall destabilization of near-surface soil aggregates. The use of cover crops during the agricultural offseason has been shown to help alleviate soil compaction and provide stabilizing effects against soil erosion, which are particularly important as the silty soils of MLRA 134 have a large erosion potential. This study evaluated the effects of cover crop and no-cover crop treatment on silt-loam soils within MLRA 134. Treatments were implemented during Fall 2018 and Fall 2019 and consisted of …


Prenatal Exposure To Per- And Polyfluoroalkyl Substances And Child Neurodevelopment, Jiwon Oh Dec 2021

Prenatal Exposure To Per- And Polyfluoroalkyl Substances And Child Neurodevelopment, Jiwon Oh

Earth & Environmental Sciences Dissertations - Archive

Pregnant women are exposed to per- and polyfluoroalkyl substances (PFAS) primarily via ingestion of contaminated food, water, and house dust. PFAS in pregnant women can be transferred to their child through the placenta during pregnancy. Many long-chain PFAS have been frequently detected in blood of pregnant women, amniotic fluid, and umbilical cord blood for the last few decades. Prenatal exposure to PFAS has shown potential to adversely affect offspring’s neurodevelopment in laboratory animals. However, epidemiological evidence on associations between prenatal PFAS exposure and child neurodevelopment remains inconsistent. My dissertation research consists of four sub-studies whose objectives are (1) to examine …


Continuous Turbidity Data Used To Compute Constituent Concentrations In The South Loup River, Nebraska, 2017–18, David L. Rus, Brenda K. Densmore Dec 2021

Continuous Turbidity Data Used To Compute Constituent Concentrations In The South Loup River, Nebraska, 2017–18, David L. Rus, Brenda K. Densmore

United States Geological Survey: Water Reports and Publications

The South Loup River in central Nebraska has been impaired by bacteria since at least 2004, which has resulted in the river not meeting its intended use as a recreational waterway. As part of a strategy for reducing the bacterial load in the river, the United States Geological Survey (USGS), in cooperation with the Lower Loup Natural Resources District, made continuous estimates of Escherichia coli (E. coli) and nutrient concentrations during seasonal monitoring at the South Loup River at Saint Michael, Nebraska, during 2017–18. Continuous turbidity data were collected from mid-April through October in 2017 and 2018 …


Reinforcement Learning Policy Gradient Methods For Reservoir Operation Management And Control, Sadegh Sadeghi Tabas Dec 2021

Reinforcement Learning Policy Gradient Methods For Reservoir Operation Management And Control, Sadegh Sadeghi Tabas

All Theses

Changes in demand, various hydrological inputs, and environmental stressors are among issues that water managers and policymakers face on a regular basis. These concerns have sparked interest in applying different techniques to determine reservoir operation policy and improve reservoir release decisions. As the resolution of the analysis rises, it becomes more difficult to effectively represent a real-world system using traditional approaches for determining the best reservoir operation policy. One of the challenges is the “curse of dimensionality,” which occurs when the discretization of the state and action spaces becomes finer or when more state or action variables are taken into …


Soil Moisture And Light Conditions Impact Digital And Visual Soil Color Assessments, Isabella Hill Dec 2021

Soil Moisture And Light Conditions Impact Digital And Visual Soil Color Assessments, Isabella Hill

All Theses

Determining soil color has traditionally been done visually, but inaccuracies with this method have been documented, including disagreement in evaluators, to differences in physical color books. Determining Munsell soil color in the field is also subject to environmental conditions, including soil water content (SWC) and light intensity. New digital spectral technology designed for determining soil color may offer accurate assessments regardless of human inaccuracies and environmental conditions. This research aimed to assess if visual observations differed from digital measurements of Munsell soil color as well as, the impacts of SWC and light on visual observations and digital measurements of soil …


Relationship Between Dike Injection And B-Value For Volcanic Earthquake Swarms, Allen F. Glazner, Stephen R. Mcnutt Dec 2021

Relationship Between Dike Injection And B-Value For Volcanic Earthquake Swarms, Allen F. Glazner, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Dike swarms are the fossil remains of regions of the crust that have undergone repeated magma injections. Volcanic earthquake swarms and geodetic measurements are, at least in part, a record of active injection of fluids (water, gas, or magma) into fractures. Here, we link these two ways of observing magmatic systems by noting that dike thicknesses and earthquake magnitudes share similar scaling parameters. In the Jurassic Independence dike swarm of eastern California median dike thickness is ∼1 m, similar to other swarms worldwide, but glacially polished exposures reveal that a typical dike comprises a number of dikelets that are lognormally …


Distinguishing Mustela From Neogale (Mustelidae) Through Both A Qualitative And Quantitative Analysis Of Skull And Tooth Morphology, Ronald W. Peery Dec 2021

Distinguishing Mustela From Neogale (Mustelidae) Through Both A Qualitative And Quantitative Analysis Of Skull And Tooth Morphology, Ronald W. Peery

Electronic Theses and Dissertations

Weasels and mink (Mustela and Neogale) can be difficult to distinguish osteologically due to similarities in morphology, thus suggesting the need for an accurate tool in distinguishing among taxa. This study utilized a combination of character state and stepwise discriminant function (DFA) analyses to examine potential distinguishing features of skull and tooth morphology. Measurements and ratios were collected from all 18 extant musteline species, as well as the extinct Neovison macrodon, Mustela rexroadensis, Mustela meltoni, Mustela gazini, and Mustela jacksoni. Unidentified musteline specimens from the Gray Fossil Site were also included. Results of …


Proliferation Of Chondrodonta As A Proxy Of Environmental Instability At The Onset Of Oae1a: Insights From Shallow-Water Limestones Of The Apulia Carbonate Platform, G. Del Viscio, G. Frijia, R. Posenato, P. Singh, Daniel J. Lehrmann, J. L. Payne, K. Al-Ramadan, U. Struck, K. P. Jochum, M. Morsilli Dec 2021

Proliferation Of Chondrodonta As A Proxy Of Environmental Instability At The Onset Of Oae1a: Insights From Shallow-Water Limestones Of The Apulia Carbonate Platform, G. Del Viscio, G. Frijia, R. Posenato, P. Singh, Daniel J. Lehrmann, J. L. Payne, K. Al-Ramadan, U. Struck, K. P. Jochum, M. Morsilli

Earth and Environmental Geosciences Faculty Research

Chondrodonta is an opportunistic, oyster-like bivalve, common in shallow-water carbonates of the Cretaceous Tethyan Realm. Despite its high abundance and widespread geographic distribution, the precise relationship between the early Aptian proliferation and environmental perturbations resulting from the Oceanic Anoxic Event 1a (OAE1a), has not been investigated. Stratigraphic and geochemical analyses of the lower Aptian Chondrodonta bedsets within the inner platform limestones of the Apulia Carbonate Platform (Gargano Promontory, southern Italy) are conducted to assess the environmental controls on the Chondrodonta proliferation and its timing and causal relationship to OAE1a. Chondrodonta occurs with sparse to common individuals within requieniid rudist floatstone–rudstones, …


Exploring Hydrologic Responses To Different Wildfire Spatial Patterns Through The Lens Of Computational Modeling, Luke M. Telfer Dec 2021

Exploring Hydrologic Responses To Different Wildfire Spatial Patterns Through The Lens Of Computational Modeling, Luke M. Telfer

Boise State University Theses and Dissertations

Severe wildfire disturbances are becoming increasingly common in high-elevation forests of the western United States. These fires alter watershed hydrologic processes, threatening critical downstream water resources and aquatic ecosystems. However, watershed-scale postfire hydrologic responses and water balance changes are highly uncertain. While postfire effects on individual processes such as runoff, infiltration, evapotranspiration, and snow dynamics are relatively well known, the role of wildfire spatial patterns in governing hydrologic connectivity and interactions between water balance components is poorly understood due to challenges associated with measuring and comparing fires at large scales. This thesis aims to examine pattern-related postfire interactions between various …


Controls On The Frequency Content Of Near-Source Infrasound At An Open-Vent Volcano (Villarrica, Chile), Bryan Blake Rosenblatt Dec 2021

Controls On The Frequency Content Of Near-Source Infrasound At An Open-Vent Volcano (Villarrica, Chile), Bryan Blake Rosenblatt

Boise State University Theses and Dissertations

The acoustic signals from open-vent volcanoes can contain specific information related to that volcano’s eruption dynamics and future activity. Thus, studying a specific volcano’s acoustics may provide critical warning mechanisms, signaling impending eruptions. Villarrica volcano, located in southern Chile, has an active lava lake that produces continuous infrasound with spectral peaks near 1 Hz and excursions of +/- ~0.2 Hz. The infrasound’s frequency content reveals key volcanic properties such as eruption style and crater shape. Leading up to Villarrica’s most recent paroxysm in 2015, infrasound spectral changes coincided with and indicated a rise in Villarrica’s lava lake level. As such, …


Effects Of Biological Cohesion On Wave Ripple Dynamics, Malcolm F. Cross Dec 2021

Effects Of Biological Cohesion On Wave Ripple Dynamics, Malcolm F. Cross

LSU New Orleans Theses and Dissertations

In coastal environments, wave-generated oscillatory flow in the bottom boundary layer mobilizes sediment resulting in bedform generation and evolution. The presence of bedforms on the seafloor affects sediment transport, wave attenuation, and acoustic scattering. Many studies have examined the dynamics of sediment transport and the development of bedforms on the seafloor due to the interaction of waves and currents. However, these studies have relied heavily on laboratory experiments undertaken using sands with no biological influence. This research aims to understand the effects of increased cohesion within the sediment particles resulting from biological influences (e.g., extracellular polymeric substances (EPS)) on the …


Analysis Of Titan's Fluvial Features Using Numerical Modeling, Jeshurun Horton Dec 2021

Analysis Of Titan's Fluvial Features Using Numerical Modeling, Jeshurun Horton

Mechanical Engineering Undergraduate Honors Theses

River channels have been observed near the Huygens probe landing site on the surface of Titan, along with evidence of rounded water ice boulders transported through fluid flow. Evidence near the landing site suggests active flow of liquid methane, which has motivated the study of the effects of sediment load and channel sizes on Titan’s fluvial features. A numerical model is used to determine the viscosity, flow velocity, and critical boulder transport diameter based on channel size, slope, and a range of sediment concentrations. This model achieves two ends: first, observed boulder diameters are used to determine the ideal channel …


Kudzu Invasion And Control In Southern Upland Forests Of Mississippi, Gina M. Profetto Dec 2021

Kudzu Invasion And Control In Southern Upland Forests Of Mississippi, Gina M. Profetto

LSU New Orleans Theses and Dissertations

Kudzu, Pueraria montana var. lobata (Willd.), is a common invasive species throughout the American South. In southern upland mixed oak-pine forests of Mississippi, kudzu invasion generally and indiscriminately suppressed the pre-invasion plant community. Three different control methods reduced kudzu density but differed in the level of reduction achieved and in their effects on the pre-existing plant community. A combination of burning and herbicides produced the most desirable outcome in terms of restoring the pre-invasion community. Kudzu invasion significantly increased nitrate pools compared to control sites, but had no effect on ammonium or nitrite, or on the microbial processes of mineralization …


Fine Grained Delta Front Sediment Transport, Sarah Noel Dec 2021

Fine Grained Delta Front Sediment Transport, Sarah Noel

LSU New Orleans Theses and Dissertations

Insights into transformative coastal processes are unlocked though understanding sediment transport mechanisms in fine-grained delta front environments. Movement of fine-grained sediments on delta fronts is not wholly explained through advection settling models. While advection settling models generally assume deposition into a still body, numerical modeling of sediment re-entrainment suggests there may be tidal, wave, and/or non-steady hydrograph influences allowing particles to reach greater distances by altering the decelerating velocity field. This research explores both an advection settling model and a mass conservation Rouse profile model to understand the irreducible delta front processes controlling sediment deposition. Using field data collected on …


Pcor Partnership Atlas, Wesley D. Peck, Earl P. Battle, Kari Suedel, Kyle A. Glazewski, Kevin C. Connors, James A. Sorensen, John A. Hamling, Charles D. Gorecki, Edward N. Steadman, John A. Harju Dec 2021

Pcor Partnership Atlas, Wesley D. Peck, Earl P. Battle, Kari Suedel, Kyle A. Glazewski, Kevin C. Connors, James A. Sorensen, John A. Hamling, Charles D. Gorecki, Edward N. Steadman, John A. Harju

EERC Maps and Infographics

The Plains CO2 Reduction (PCOR) Partnership Atlas provides a regional profile of CO2 sources and potential storage locations across the PCOR Partnership region. The sixth edition provides an up-to-date look at PCOR Partnership initiative activities, including additional regional characterization and updates on commercial projects. Additional background information on carbon capture, utilization, and storage (CCUS) is included to give a better understanding of how CCUS addresses concerns about climate change while allowing future energy needs to be met.


Soil Gypsum Content Analysis Of The Proposed Road Route Extension Of Fm 2185 In The Gypsum Plain, Culberson County, Texas, Chikaodili Ohakawa Dec 2021

Soil Gypsum Content Analysis Of The Proposed Road Route Extension Of Fm 2185 In The Gypsum Plain, Culberson County, Texas, Chikaodili Ohakawa

Electronic Theses and Dissertations

Soils serve as the underlying substrate on which foundations for most structures are built. The properties of a soil type are therefore an important consideration in building engineered structures. Gypsic soils are problematic for construction of such structures. One of the main problems with gypsic soils is dissolution. Gypsum (CaSO4·2H2O) in soils dissolves easily creating voids which can be detrimental to the integrity of engineering structures. To mitigate this, it is important to determine the amount of gypsum present in soils, before construction is initiated.

In this study, three methods were employed in the determination of …


Factors Controlling Longshore Variations Of Beach Changes Induced By Hurricane Hermine Along Pinellas County Beaches, West-Central Florida, Wenhan Zhai Dec 2021

Factors Controlling Longshore Variations Of Beach Changes Induced By Hurricane Hermine Along Pinellas County Beaches, West-Central Florida, Wenhan Zhai

USF Tampa Graduate Theses and Dissertations

Hurricane Hermine, 2016, impacted the coast of west-central Florida and generated high waves superimposed on elevated wave levels which caused significant beach erosion. A total of 122 profiles, spaced about 300 m apart, were surveyed 2 weeks before and one week after the storm to examine the beach changes along three barrier islands along the coast of west-central Florida. including Sand Key, Treasure Island and Long Key. In order to investigates the longshore variations of beach/nearshore changes induced by storm, several parameters were defined and calculated including beach volume changes, berm height, beach width, foreshore slope, as well as sandbar …


Fire Effects On Soil Properties: Amending Post-Fire Soils With Native Microbial Communities And Biochar To Improve Sagebrush Performance, Sabrina Marie Schuler Dec 2021

Fire Effects On Soil Properties: Amending Post-Fire Soils With Native Microbial Communities And Biochar To Improve Sagebrush Performance, Sabrina Marie Schuler

Boise State University Theses and Dissertations

Within the sagebrush steppe, fire has been shown to affect biogeochemical properties and the microbial community composition in soils. However, there is uncertainty about the magnitude and direction of these effects, since they vary by sites that differ in abiotic and biotic conditions. Moreover, differences in post-fire management strategies are likely to mediate the effect of fire on soil properties, thus further compounding this uncertainty. Any changes in soil biogeochemical properties following fire can prevent successful restoration of Artemisia tridentata sp. wyomingensis (sagebrush), leading to variable outcomes of restoration success in the sagebrush steppe. Previous research has shown that addition …


Water Quality Responses To A Semi-Arid Beaver Meadow In Boise, Idaho, Luise Bayer Winslow Dec 2021

Water Quality Responses To A Semi-Arid Beaver Meadow In Boise, Idaho, Luise Bayer Winslow

Boise State University Theses and Dissertations

Beavers have been instrumental in shaping the North American riverine landscape. However, land use change and beaver trapping have caused large decreases in beaver populations, resulting in fundamental changes to river morphology, hydrology, and biogeochemical function. Effective river restoration and remediation of arid western rivers relies on a comprehensive interpretation of how beaver activity influences water quantity and quality. In this study, I compared two stream reaches with and without beaver dams in a semi-arid watershed, to quantify the effects of beaver activity on hydrology and biogeochemistry. Within each reach, I combined dilution gauging and stream tracer experiments to determine …


Snook (Centropomus Undecimalis) Behavior And Accelerometer Telemetry In The Bahia Grande Of Texas, Jonathan Truett Cawlfield Dec 2021

Snook (Centropomus Undecimalis) Behavior And Accelerometer Telemetry In The Bahia Grande Of Texas, Jonathan Truett Cawlfield

Theses and Dissertations

There has been very little study of the Texas population of snook. No studies have have looked at behavior in the Texas snook population. In this study we look at behavioral patterns and activity level in Lower Laguna Madre snook utilizing accelerometer telemetry tags. Twenty-one common snook were surgically implanted with tags and monitored from summer and fall of 2019 until September 2020. The accelerometer tags which sum acceleration over the x, y, and z planes calculated (ODBA) which was used to estimate behavior. This behavior was then compared with environmental data like diel period, tidal period, water temperature, and …


Using Sedimentary Mercury Geochemistry To Evaluate The Niagara-Salina Transition, Silurian Michigan Basin, Usa, Sara Hayes Dec 2021

Using Sedimentary Mercury Geochemistry To Evaluate The Niagara-Salina Transition, Silurian Michigan Basin, Usa, Sara Hayes

Masters Theses

The Niagara-Salina boundary in the Michigan Basin is marked by an abrupt transition from carbonates to evaporites. Though the cause is uncertain, previous work suggests the onset of Salina evaporites was driven by basin restriction, but the presence of several global carbon isotope excursions (CIE) suggest a global driver. This study builds on this discussion using two relatively new geochemical proxies - elemental mercury concentrations [Hg] and Hg isotopes.

Mercury concentrations [Hg] were measured in 88 samples from the State Kalkaska #2-15 core from 6604.03 ft to 6797.42 ft. [Hg] ranges from 0.11 to 0.62 mg/kg and [Hg]/TOC from 0.038 …


Understanding The Multiple Small Magnitude Induced Seismic Soil Fatigue Potential On Hazard Assessments, Merissa L. Zuzulock, Oliver Denzil S. Taylor, Norbert H. Maerz Dec 2021

Understanding The Multiple Small Magnitude Induced Seismic Soil Fatigue Potential On Hazard Assessments, Merissa L. Zuzulock, Oliver Denzil S. Taylor, Norbert H. Maerz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Soils under spacio-temporally clustered events loading are susceptible to soil fatigue as pore pressure dissipates and the soil is unable to recover. This potential for damage from soil fatigue is identified through an induced seismic fatigue equation provided in this paper. The objective of this paper is to present an induced seimic equation for soils under spacio-temporally clustered impulse loading to identify potential hazards to the subsurface that supports critical infrastructure. It further illustrates the use of the equation as determined from a comparison of three varying soil profiles with resulting data that shows a need to establish new critieria …


Fingerprinting The Cretaceous-Paleogene Boundary Impact With Zn Isotopes, Ryan Mathur, Brandon Mahan, Marissa Spencer, Linda Godfrey, Neil Landman, Matthew Garb, D. Graham Pearson, Sheng-Ao Liu, Francisca Oboh-Ikuenobe Dec 2021

Fingerprinting The Cretaceous-Paleogene Boundary Impact With Zn Isotopes, Ryan Mathur, Brandon Mahan, Marissa Spencer, Linda Godfrey, Neil Landman, Matthew Garb, D. Graham Pearson, Sheng-Ao Liu, Francisca Oboh-Ikuenobe

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Numerous geochemical anomalies exist at the K-Pg boundary that indicate the addition of extraterrestrial materials; however, none fingerprint volatilization, a key process that occurs during large bolide impacts. Stable Zn isotopes are an exceptional indicator of volatility-related processes, where partial vaporization of Zn leaves the residuum enriched in its heavy isotopes. Here, we present Zn isotope data for sedimentary rock layers of the K-Pg boundary, which display heavier Zn isotope compositions and lower Zn concentrations relative to surrounding sedimentary rocks, the carbonate platform at the impact site, and most carbonaceous chondrites. Neither volcanic events nor secondary alteration during weathering and …