Geology Commons^™

Reconstructing 5000 Years Of Hurricane Activity In Holyrood Pond Using Sediment Core Analysis, Jamie Mclaulin, Arielle Nogueira, Elizabeth Wallace

Knowledge and Creativity Expo

Hurricanes are hazardous and costly events that annually negatively impact people that live in coastal areas in North America.  The current observational record of hurricanes is short (1970- present) and does not offer insight into the effects of climate change on hurricane frequency.  One method of improving and extending our observational record of hurricanes is to reconstruct paleohurricanes using sediment cores.  These cores record hurricane activity in the form of coarse-grained overwash layers that are deposited when hurricanes move sand from beaches into backbarrier ponds.  In this project, we analyzed sediment cores from Atlantic Canada to locate coarse-grained storm layers …

Testing The Limits Of Provenance Analysis From Basaltic Fluvial Sediment Near Sandvatn, Iceland, As A Mars Analog, Audrey R. Putnam, Kirsten L. Siebach, Michael T. Thorpe, Valerie M. Tu, Elizabeth B. Rampe, Candice C. Bedford, Gelu Costin, Joseph J. Tamborski

OES Faculty Publications

Detrital sediments that accumulate downstream and are preserved in sedimentary rocks can allow characterization of geologic formations that are inaccessible for spatial or temporal reasons. However, mixing, sorting, and alteration of sediment during transport may complicate reconstruction of protolith characteristics. We test the preservation of three key provenance signals in coarse fluvial sand at a Mars analog watershed in Iceland to determine whether detrital sediments capture (a) watershed magmatic chemical variation, (b) textural indicators of lava-water interaction during eruption and cooling, and (c) hydrothermal alteration. Specifically, we tested whether diagnostic variations in rock mineralogy, chemistry, and texture can be recovered …

The Effects Of A Microplate On Plume-Ridge Interactions: Constraints From Comparing Easter And Juan Fernandez Microplates In The Eastern Pacific Ocean, Katherine Ames, Jennifer Georgen

OES Faculty Publications

This study investigates the nature of plume-ridge interactions near a tectonic microplate using mantle Bouguer anomaly (MBA) gravity calculations. The focus of this investigation is a comparison of the Easter and Juan Fernandez microplates, which are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. The microplates have several similar characteristics, including general size, time of formation, and clockwise rotation within the larger bounding mid-ocean ridge systems. Unlike the Juan Fernandez microplate, however, the Easter microplate is located near a mantle plume (Easter/Salas y Gomez). Previously published geochemical data suggest that material from this plume …

Nonstationary Spatial Correlation Of Earthquake Ground Motions In California, Pengfei Wang, Busra Bocekli, Junhui Yang, Scott J. Brandenberg, Jonathan P. Stewart

Civil & Environmental Engineering Faculty Publications

Assessing seismic risk to spatially distributed infrastructure systems requires realistic representations of spatially correlated ground motions. Existing models for the spatial correlations of ground motions rely on strong second-order stationarity assumptions, under which the correlation structure is assumed to be invariant across space, potentially masking regional variations. Because repeatable site and path effects can vary spatially, the resulting correlation structure is likely to be nonstationary. We propose a nonstationary spatial correlation method that captures geographically varying correlation decay behavior. We compute site-to-site Pearson correlations of within-event residuals using earthquakes recorded at both sites in each site pair and model the …

Flood-Season Surface Water-Groundwater Interactions Across Distinct Geomorphic Units In A Yellow River Great Bend Tributary Basin, Yinlong Wang, Ruizhong Gao, Debin Jia, Xixi Wang, Tingxi Liu, Xiaomin Liu, Shiming Bai

Civil & Environmental Engineering Faculty Publications

Surface water-groundwater interactions are complex in the Great Bend region of the Yellow River. Clarifying water exchange and source differences among geomorphic units is important for understanding regional hydrological processes and improving water resources management. In this study, the Wulanmulun River Basin, a typical tributary of the Yellow River, was selected as the study area. A total of 90 water samples were collected, including 25 river water samples, 43 groundwater samples, and 22 precipitation samples. Gibbs diagrams, multivariate statistical analysis, PMF, and MixSIAR models were used to investigate the hydrochemical and isotopic characteristics, source contributions, and transformation relationships of surface …

Evidence For Distal Bolide Impact And Tsunami Deposits In The Upper Atlantic Coastal Plain Of Moore County (North Carolina, Usa) Generated By The Eocene Chesapeake Bay Bolide Impact, G. Robert Ganis, Ralph H. Willoughby, David J. Cicimurri, G. Richard Whittecar, Steven J. Hageman

OES Faculty Publications

Beds interpreted as Eocene bolide-generated impact and tsunami deposits occur at Paint Hill in the Upper Atlantic Coastal Plain of Moore County, North Carolina, USA. These strata, herein named the Mount Helicon Formation, consist of four distinct beds comprising about one meter of total section. Bed 1 (the basal bed) is approximately 43 cm thick and consists of sandy carbonaceous clay with carbon glass and rock fragments and contains 14-18 parts per billion (ppb) iridium (interpreted as bolide impact ejecta). Bed 2 is approximately 9 cm thick and consists of non-cohesive silt-size particles and loosely bound sand-size accretionary lapilli-like masses …

08 - Blue Carbon Sequestration And Sediment Storage In Seagrass Meadows Of South Bay, Luke C. Clements, Adriana Amrhein, Richard P. Hale

Undergraduate Research Symposium

Blue carbon is stored in coastal and marine ecosystems like seagrass meadows and salt marshes, which helps combat climate change by preventing greenhouse gas emissions. This study examines the role of seagrass in carbon storage by comparing sediment cores from a mud channel and a seagrass meadow in South Bay.

We collected a 100 cm core from the mud channel and a 55 cm core from the seagrass area, taking samples every 10 cm to analyze grain size and organic carbon content. Using a wet sieving method, we separated sand from mud and measured organic carbon through loss on ignition. …

Biogenic Modification Of Tidally Modified Substrates From The Micro- To Macroscopic Scale, Rogers Clark Caldwell Buntin Ii

OES Theses and Dissertations

Digital outcrop models generated by high-resolution photogrammetric imagery permit investigations into organism-substrate interactions at the centimeter to sub-millimeter scale. This dissertation uses this three-dimensional technology to study two sedimentary successions— the Archaean Dresser Formation and Cretaceous Dakota Sandstone— by capturing images via unmanned aircraft systems and single lens reflex cameras. The ~3.48 Ga Dresser Formation provides evidence for some of the earliest life on Earth in the form of stromatolites and microbially induced sedimentary structures. Aerial imagery of the 3.5 km2 Buick Geoheritage reserve capture the site’s geologic structures and close-range imagery documents stromatolites and several microbially induced sedimentary structures …

Microbial Mats In Dinosaur Ichnocoenoses, Nora Noffke, Paul C. Murphey, Roger C. Buntin, Martin G. Lockley

OES Faculty Publications

Until now, the significance of microbial mats in preservation of dinosaur tracks and in reconstructing the palaeoenvironment in which dinosaurs roamed was rarely studied. Dinosaur tracks are commonly found close to ancient aquatic bodies where moist sediment had once allowed footstep registration. At such sites, epibenthic or endobenthic microbial mats may have developed as well and may have led to exquisite track preservation. Microbial mats in coastal, lacustrine or flood plain environments cause ‘microbially induced sedimentary structures—MISS’, which are micobialites found in sandy or evaporitic settings. The microbial structures record environmental parameters including meteorological conditions that existed at the time …

4500-Year Paleohurricane Record From The Western Gulf Of Mexico, Coastal Central Tx, Usa, Sarah B. Monica, Davin J. Wallace, Elizabeth J. Wallace, Xiaojing Du, Sylvia G. Dee, John B. Anderson

OES Faculty Publications

Texas receives the second-highest number of tropical cyclone (TC) landfalls per year in the United States. At present, long-term TC projections from climate models remain uncertain due to the short and biased nature of Atlantic TC observations. Sediment archives of past storms can help extend the observational record of TC strikes over the past few millennia. When a TC makes landfall along the central Texas coast, coastal downwelling channels and storm currents transport and deposit coarse sediment to a zone of rapid accumulation along the shelf, known as the Texas Mud Blanket (TMB). This “backwash” process results in expansive storm …

Ice-Marginal Volcanic Sequence In Iceland Found On A Nondescript Gradual Hillslope: An Unexpected Record Of Ice Thickness Late In Deglaciation, Audrey R. Putnam, Kristen L. Siebach, Candice C. Bedford, Sarah L. Simpson, Michael T. Thorpe, Joseph J. Tamborski

OES Faculty Publications

Volcanism increases when glaciers melt because isostatic rebound during deglaciation decreases the pressure on the mantle, which enhances decompression melting. Anthropogenic climate change is now causing ice sheets and valley glaciers to melt around the world and this deglaciation could stimulate volcanic activity and associated hazards in Iceland, Antarctica, Alaska, and Patagonia. However, current model predictions for volcanic activity associated with anthropogenic deglaciation in Iceland are poorly constrained, in part due to uncertainties in past volcanic output over time compared to ice sheet arrangements. Further work specifically characterizing glaciovolcanic and ice-marginal volcanoes in Iceland is needed to reconstruct volcanic output …

A General Framework For Modeling Subregional Path Effects, T. E. Buckreis, P. Wang, S. J. Brandenberg, J. P. Stewart

Civil & Environmental Engineering Faculty Publications

Next Generation Attenuation (NGA) West2 ground motion models (GMMs) include regional path adjustments for broad jurisdictional regions, which necessarily averages spatially variable path effects within those regions. We extend that framework to account for systematic variations in attenuation within subregions defined in consideration of geologic differences. In recent years, cell-based methods which systematically account for spatial variations by summing the attenuation effects over a fine discretization of uniform-rectangular cells (e.g., Dawood and Rodriquez-Marek 2013; Kuehn et al. 2019) have been shown to be an effective alternative to regionalization and a step towards modelling non-ergodic path effects. The main drawbacks of …

History Of Ice-Rafting In The Arctic Ocean During Glacial Maxima Through Marine Isotope Stage 6, Shannon M. Cofield

OES Theses and Dissertations

Numerous studies attempted to reconstruct Arctic paleoclimate, specifically ice mass timing and locations, during glacial maxima. While some regions, like the Barents-Svalbard Ice Sheet (BSIS) are well-studied, they may benefit from a high-resolution paleo proxy. Other regions are highly contested, such as the East Siberian Sea or the presence of a central Arctic Ocean ice mass.

This research uses an Fe-grain provenance method to (1) define how the BSIS behaved during Marine Isotope Stage (MIS) 2, 4, and 6, and when it retreated; (2) determine the presence and ages of Shelf Ice Masses (SIMs) in the Beaufort Sea and East …

An Integrative Salt Marsh Conceptual Framework For Global Comparisons, Erik S. Yando, Scott F. Jones, W. Ryan James, Denise D. Colombano, Diana I. Montemayor, Stefanie Nolte, Jacqueline L. Raw, Shelby L. Ziegler, Luzhen Chen, Daniele Daffonchio, Marco Fusi, Kerrylee Rogers, Liudmila Sergienko

Biological Sciences Faculty Publications

Salt marshes occur globally across climatic and coastal settings, providing key linkages between terrestrial and marine ecosystems. However, salt marsh science lacks a unifying conceptual framework; consequently, historically well-studied locations have been used as normative benchmarks. To allow for more effective comparisons across the diversity of salt marshes, we developed an integrative salt marsh conceptual framework. We review ecosystem-relevant drivers from global to local spatial scales, integrate these multi-scale settings into a framework, and provide guidance on applying the framework using specific variables on 11 global examples. Overall, this framework allows for appropriate comparison of study sites by accounting for …

Revisiting 228Th As A Tool For Determining Sedimentation And Mass Accumulation Rates, Joseph J. Tamborski, Pinghe Cai, Meagan Eagle, Paul Henderson, Matthew A. Charette

OES Faculty Publications

The use of ²²⁸Th has seen limited application for determining sedimentation and mass accumulation rates in coastal and marine environments. Recent analytical advances have enabled rapid, precise measurements of particle-bound ²²⁸Th using a radium delayed coincidence counting system (RaDeCC). Herein we review the ²²⁸Th cycle in the marine environment and revisit the historical use of ²²⁸Th as a tracer for determining sediment vertical accretion and mass accumulation rates in light of new measurement techniques. Case studies comparing accumulation rates from ²²⁸Th and ²¹⁰Pb are presented for a micro-tidal salt marsh and a marginal sea …

A Demonstration Of A Simple Methodology Of Flood Prediction For A Coastal City Under Threat Of Sea Level Rise: The Case Of Norfolk, Va, Usa, Tal Ezer

CCPO Publications

Many coastal cities around the world are at risk of increased flooding due to sea level rise (SLR), so here a simple flood prediction method is demonstrated for one city at risk, Norfolk, VA, on the U.S. East Coast. The probability of future flooding is estimated by extending observed hourly water level for 1927–2021 into hourly estimates until 2100. Unlike most other flood prediction methods, the approach here does not use any predetermined probability distribution function of extreme events, and instead a random sampling of past data represents tides and storm surges. The probability of flooding for 3 different flood …

Reconstructing Surface Water Carbonate Ion Concentration Changes In The Eastern Equatorial Pacific Across Glacial Transitions, Lenzie Gail Ward

OES Theses and Dissertations

Today, the eastern equatorial Pacific (EEP) plays a critical role in the global CO₂ budget as a major source of CO₂ to the atmosphere, but recent studies suggest the region may shift to a sink for atmospheric CO₂ under different climate states. Here, I focus on two transitional periods, the last deglaciation (25 kyr to present) and last glaciation (the Marine Isotope Stage (MIS) 5a-4 transition, 96 to 60 kyr), to investigate how the carbon system in the EEP responds to major climate changes. I measured B/Ca ratios in the planktic foraminifera Globigerina bulloides from core MV1014-17JC …

Salt Marsh Hydrogeology: A Review, Julia Guimond, Joseph Tamborski

OES Faculty Publications

Groundwater–surface water exchange in salt marsh ecosystems mediates nearshore salt, nutrient, and carbon budgets with implications for biological productivity and global climate. Despite their importance, a synthesis of salt marsh groundwater studies is lacking. In this review, we summarize drivers mediating salt marsh hydrogeology, review field and modeling techniques, and discuss patterns of exchange. New data from a Delaware seepage meter study are reported which highlight small-scale spatial variability in exchange rates. A synthesis of the salt marsh hydrogeology literature reveals a positive relationship between tidal range and submarine groundwater discharge but not porewater exchange, highlighting the multidimensional drivers of …

Constraining Respired Carbon Storage In The Eastern Tropical Pacific Over The Last 25 Thousand Years Using Benthic Foraminiferal Boron/Calcium Ratios, Brian James Close

OES Theses and Dissertations

The storage of inorganic carbon in the deep Pacific Ocean is thought to play an important role in regulating both glacial-interglacial and millennial-scale atmospheric CO₂ concentrations (Broecker and Barker 2007; Sigman et al., 2010). A recent study by Loveley et al. (2017) showed that sedimentary authigenic uranium (aU) concentrations, a proxy for suboxic bottom-water conditions, increased significantly in the Eastern Equatorial Pacific (EEP) during the Last Glacial Maximum (LGM, 18 kyr – 23 kyr). If this is correct, the low-oxygen, CO_2-rich waters would also have a lower pH and a lower carbonate ion concentration ([CO₃^{2- …}

Surface Elevation And Sedimentation Dynamics In The Ganges-Brahmaputra Tidal Delta Plain, Bangladesh: Evidence For Mangrove Adaptation To Human-Induced Tidal Amplification, Edwin J. Bomer, Carol A. Wilson, Richard Hale, Abu Naser Mohsin Hossain, F.M. Arifur Rahman

OES Faculty Publications

In the Ganges-Brahmaputra (G-B) delta, periodic flooding of the land surface during the tidal cycle coupled with enormous sediment delivery during the monsoon promotes sediment accretion and surface elevation gain through time. However, over the past several decades, widespread embankment (“polder”) construction in the GB tidal delta plain has led to numerous environmental disturbances, including channel siltation and tide range amplification. While previous research indicates that rates of sediment accretion are relatively high in the G-B tidal delta plain, it remains unclear if and how surface elevation is maintaining pace with relative sea-level rise (RSLR) in this region. In this …

Vertical Land Displacement Rates And Uncertainty In Hampton Roads, Va [Dataset], Brett Buzzanga, David P. S. Bekaert, Ben D. Hamlington, Simran S. Sangha

CCPO Data Sets

These data contain vertical rates (mm/yr) of surface land displacements and their associated uncertainties from 2015-03-15 to 2019-06-01.

They are associated with Buzzanga, B. A., Bekaert, D. P. S., Hamlington, B. D., and Sanga, S. (2020), "Towards Sustained Monitoring of Subsidence at the Coast Using InSAR and GNSS: An Application in Hampton Roads, Virginia. Geophysical Research Letters.

Corrigendum To "Upper Water Structure And Mixed Layer Depth In Tropical Waters: The Seats Station In The Northern South China Sea, Jen-Hua Tai, George T.F. Wong, Xiaoju Pan

OES Faculty Publications

No abstract provided.

Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Elizabeth L. Chamberlain, Steven L. Goodbred, Richard Hale, Michael S. Steckler, Jakob Willinga, Carol Wilson

OES Faculty Publications

Constraining time is of critical importance to evaluating the rates and relative contributions of processes driving landscape change in sedimentary basins. The geomorphic character of the field setting guides the application of geochronologic or instrumental tools to this problem, because the viability of methods can be highly influenced by geomorphic attributes. For example, sediment yield and the linked potential for organic preservation may govern the usefulness of radiocarbon dating. Similarly, the rate of sediment transport from source to sink may determine the maturity and/or light exposure of mineral grains arriving in the delta and thus the feasibility of luminescence dating. …

Sediment Resuspension In A Microtidal Estuary: Causative Forces And Links With Algal Blooms, Samantha C. Mcgill

OES Theses and Dissertations

After years of efforts to restore the Chesapeake Bay, bacterial levels are down and species diversity has increased, however, algal blooms (primarily dinoflagellates) persist, occurring nearly every summer. Dinoflagellates produce resting cysts that accumulate in the bottom sediments and are thought to provide seed populations for future algal blooms when they are resuspended. When estuarine sediments are advected from a bed, other materials, such as pollutants, nutrients, and organic matter are also released into the water column. Thus, resuspended sediments can contribute to the degradation of water quality, habitat, and aquatic life, and impart negative impacts on local ecosystems and …

Circum-Arctic Mineralogy & Pan-Arctic Chronostratigraphy Of Late Pleistocene Sediments: Developing A Comprehensive Age Model For The Western Arctic Ocean Using Unique Ice-Rafted Signals, Wesley Blake Myers

OES Theses and Dissertations

To improve understanding of geographic mineral distribution from the circum-Arctic Ocean, samples from the Arctic periphery were collected and analyzed for (semi-) quantitative mineral composition. Most samples were collected from the North American region of the Arctic Ocean, a region which has had limited mineral investigation. In addition, more than 1000 published clay mineral data points were gathered to provide the most comprehensive clay mineral distribution map to date. The identification of a smectite source within the Canadian Arctic may reduce the usefulness of this mineral as a unique provenance signal for the Eurasian region. Smectite speciation may be useful …

Pacts 1.0: A Crowdsourced Reporting Standard For Paleoclimate Data, D. Khider, J. Emile-Geay, N. P. Mckay, Y. Gil, D. Garijo, V. Ratnakar, M. Alonso-Garcia, S. Bertrand, O. Bothe, P. Brewer, A. Bunn, M. Chevalier, L. Comas-Bru, J. Hertzberg, Y. Zhou

OES Faculty Publications

The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of …

Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown

OES Theses and Dissertations

The Ganges-Brahmaputra-Meghna (GBM) Delta is one of the largest deltas in the world, covering more than 100,000 km². The GBM River system transports over one billion tons of sediment annually and delivers ~750 million tons to the Bay of Bengal, ~25% of which is advected by tides into the fluvially abandoned western delta plain. The Sundarbans National Forest (SNF) is located within the GBM Delta and, covering more than 10,000 km², is the world’s largest continuous mangrove stand. The present rate of sediment delivery allows the SNF platform elevation to keep pace with regional sea level …

Rates Of Relative Sea Level Rise Along The United States East Coast, Jesse N. Beckman, Joseph E. Garcia

Virginia Journal of Science

Recent studies have indicated that some coastal areas, including the East Coast of the United States, are experiencing higher rates of sea level rise than the global average. Rates of relative sea level rise are affected by changes in ocean dynamics, as well as by surface elevation fluctuations due to local land subsidence or uplift. In this study, we derived long-term trends in annual mean relative sea level using tide gauge data obtained from the Permanent Service for Mean Sea Level for stations along the United States East Coast. Stations were grouped by location into the Northeast, Mid-Atlantic, and Southeast …

The Effect Of Evapotranspiration On The Groundwater Dome And Past Drought Conditions At Cape Henry, Virginia, Bryce Omar Shoup

OES Theses and Dissertations

First Landing State Park, located in Virginia Beach, is a cuspate foreland developed from a succession of erosional and progradational events forming a series of dunes and interdunal swales. Low-lying swales dominate the southern portion of the park forming many wetlands, but the northern portion of the park has fewer wetlands. An asymmetric groundwater dome has been observed on Cape Henry, cresting north of the geographic center of the cuspate foreland. The purpose of this study was to determine if the wetlands that dominate the southern portion of the park are the major driver of the asymmetric groundwater dome and …

A Deep Eastern Equatorial Pacific Thermocline During The Last Glacial Maximum, H. L. Ford, C. L. Mcchesney, J. E. Hertzberg, J. F. Mcmanus

OES Faculty Publications

The mean state and variability of the tropical Pacificis influenced by the depth of the thermocline. During the Last Glacial Maximum (~21,000 years ago), the zonal sea surface temperature gradient across the equatorial Pacific was reduced and productivity was generally lower than modern. To understand the thermocline depth’s role in determining the Last Glacial Maximum tropical mean state, we reconstruct the upper ocean δ¹⁸O profile from multiple species of planktic foraminifera. We synthesize existing records of surface and subsurface dwelling foraminifera to reconstruct the vertical δ¹⁸O gradient throughout the eastern equatorial Pacific. We find the thermocline …