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Articles 301 - 330 of 2258
Full-Text Articles in Earth Sciences
Effect Of Pre-Existing Fault Orientation On Strain Localization In A Foliated Granitic Gneiss, Geoffrey Hilliard
Effect Of Pre-Existing Fault Orientation On Strain Localization In A Foliated Granitic Gneiss, Geoffrey Hilliard
Williams Honors College, Honors Research Projects
The effect of fault orientation relative to the applied stress on reactivation of pre-existing brittle faults instead of forming new faults is well-explained by Mohr-Coulomb theory. However, Mohr-Coulomb theory does not explain the effect of orientation on reactivation of faults with a ductile rheology and no work has been performed to assess the effect of orientation of a pre-existing ductile fault on fault strength. In order to determine how rock strength and localization of strain into a ductile fault is affected when the orientation of the pre-existing fault (artificial fault) is changed, experiments were performed on pre-faulted cores of a …
Biotic Characteristics Of Managed And Unmanaged Coastal Dunes In The Outer Banks, North Carolina, Andrew E. White
Biotic Characteristics Of Managed And Unmanaged Coastal Dunes In The Outer Banks, North Carolina, Andrew E. White
Theses and Dissertations
Under future climate change and sea level rise scenarios, Natural and Nature-Based Features (e.g., dunes) that protect coastal habitat and infrastructure will be exposed to increased wave energy and storm surge. Understanding how these forces will impact coastal dunes is necessary for their continued use as protective features. Coastal dunes develop through feedback between vegetation and sediment deposition, a process complicated by species-specific growth rates and responses to burial. Wave flume studies have tested the effects of dune vegetation on erosion and found multiple plant organs across several functional types to be important for resisting erosion. Although dune building and …
Evidence For Metabolic Diversity In Meso-Neoproterozoic Stromatolites (Vazante Group, Brazil), Flavia Callefo, Fresia Ricardi-Branco, Mirian Mírian Liza Alves Forancelli Pacheco, Alexandre Ribeiro Cardoso, Nora Noffke, Verônica De Carvalho Teixeira, Itamar Tomio Neckel, Lara Maldanis, Emma Bullock, Dina Bower, Adalene Moreira Silva, Dario Ferreira Sanchez, Fabio Rodrigues, Douglas Galante
Evidence For Metabolic Diversity In Meso-Neoproterozoic Stromatolites (Vazante Group, Brazil), Flavia Callefo, Fresia Ricardi-Branco, Mirian Mírian Liza Alves Forancelli Pacheco, Alexandre Ribeiro Cardoso, Nora Noffke, Verônica De Carvalho Teixeira, Itamar Tomio Neckel, Lara Maldanis, Emma Bullock, Dina Bower, Adalene Moreira Silva, Dario Ferreira Sanchez, Fabio Rodrigues, Douglas Galante
OES Faculty Publications
Deciphering the evolution of ecological interactions among the metabolic types during the early diversification of life on Earth is crucial for our understanding of the ancient biosphere. The stromatolites from the genus Conophyton cylindricus represent a datum for the Proterozoic (Meso to Neoproterozoic) on Earth. Their typical conical shape has been considered a result of a competition between microorganisms for space, light and nutrients. Well-preserved records of this genus from the "Paleontological Site of Cabeludo ", Vazante Group, São Francisco Craton (Southern Brazil) present in situ fossilized biofilms, containing preserved carbonaceous matter. Petrographic and geochemical analyses revealed an alternation between …
Strange Stones Of Skull Creek: Basalt Glacial Erratics And Omars In Eastern Nebraska, Robert M. Joeckel, Jesse T. Korus, Judith Turk, C. C. Arps, N. V. Arps, Leslie M. Howard
Strange Stones Of Skull Creek: Basalt Glacial Erratics And Omars In Eastern Nebraska, Robert M. Joeckel, Jesse T. Korus, Judith Turk, C. C. Arps, N. V. Arps, Leslie M. Howard
Conservation and Survey Division: Faculty and Staff Publications
We describe unusual stream- reworked glacially transported rocks (erratics) from a locality 50 km east of the limit of all pre- Illinoian (pre- 190 ka) Pleistocene glaciations in the central USA. Almost all these erratics consist of the igneous rock basalt, and of those, the vast majority have at least one fl at, smooth face. Some have two or more such faces that meet at obtuse angles along one or more well- defi ned, straight edges. We attribute these features, as well as laminations, plumose marks, and other features, to columnar jointing in ancient lava fl ows and shallow intrusions. …
The Impact Of Sampling Methodology On Soil Bulk Density Measurement By The Clod Method, Aldi J. Airori, Trinity Baker, Judith Turk
The Impact Of Sampling Methodology On Soil Bulk Density Measurement By The Clod Method, Aldi J. Airori, Trinity Baker, Judith Turk
Conservation and Survey Division: Faculty and Staff Publications
The clod method is a widely used and accurate bulk density method. However, its use is limited to sampling from soil pits. This study was conducted to: 1) determine whether clods collected from cores provide similar bulk density measurements to those collected from soil pits and 2) evaluate the impact of various clod bulk density methods on carbon stock calculation. Clods were collected from soil pits, 5.1 cm soil cores, and 8.9 cm soil cores. Three-dimensional laser scanning was used to measure the volume of the soil clods before and after oven-drying and bulk density was calculated as the dry …
Amphibians And Reptiles Of Nebraska Coloring Pages, John Lokke
Amphibians And Reptiles Of Nebraska Coloring Pages, John Lokke
Conservation and Survey Division: Faculty and Staff Publications
Black and white images from original art by John Lokke. Suitable for coloring pages. Published by the Nebraska Maps & More Store at the School of Natural Resources, University of Nebraska - Lincoln.
Hydrogeomorphic Response Of Steep Streams Following Severe Wildfire In The Western Cascades, Oregon, David Matthew Busby
Hydrogeomorphic Response Of Steep Streams Following Severe Wildfire In The Western Cascades, Oregon, David Matthew Busby
Graduate Student Theses, Dissertations, & Professional Papers
Severe wildfire may alter the morphologic resilience of steep mountain streams by increasing peak discharges, elevating inputs of sediment and wood into channels, and increasing susceptibility to landslides and debris flows. In the Pacific Northwest, where mean annual precipitation is high and mean fire return intervals range from decades to centuries, understanding of steep stream response to fire is limited. In 2020, the Western Cascade Range, Oregon, experienced wildfire of historic magnitude and severity. The objective of this study was to evaluate the hydrologic and geomorphic response of steep streams to the 2020 fires. I assessed streamflow, instream wood, and …
Development Of Regional Landslide Susceptibility Models: A First Step Towards Model Transferability, Gina M. Belair
Development Of Regional Landslide Susceptibility Models: A First Step Towards Model Transferability, Gina M. Belair
Graduate Student Theses, Dissertations, & Professional Papers
Landslides are a globally pervasive problem with the potential to cause significant fatalities and economic losses. Although landslides are widespread, many at-risk regions may not have the high-quality data or resources used in most landslide susceptibility analyses. This study aims to develop regional susceptibility relationships that are versatile and use publicly available data and open-sourced software. Logistic Regression and Frequency Ratio susceptibility relationships were developed in 23 regions in Washington, Utah, North Carolina, and Kentucky, with a region referring to a unique area and data combination. Regions were diverse in their geology, morphology, climate, and nature and quality of their …
Mining-Contaminated Sediment And Metal Storage In Channel Deposits In Turkey Creek, Tri-State Mining District, Missouri And Kansas, Max Quinn Hillermann
Mining-Contaminated Sediment And Metal Storage In Channel Deposits In Turkey Creek, Tri-State Mining District, Missouri And Kansas, Max Quinn Hillermann
Graduate Theses/Dissertations
The Joplin subdistrict, within the Tri-State Mining District (TSMD), was a major producer of lead (Pb) and zinc (Zn) ore between the 1880s to 1920s. Metalliferous mining wastes are still stored in the channel deposits of local streams raising environmental and health concerns. This study quantifies the volume, sediment size, and metal concentrations in channel bed, bar, bench, and chute deposits to quantify the spatial variability of contaminated sediment storage in Turkey Creek (119 km2). Sample reaches (n=14) contained metal concentrations elevated above the Tri-State Mining District specific probable effects concentration at every site with mean concentrations in …
Downstream Dispersal Of Fine Tailings, Chat And Metals In Channel Sediment Of Big River, Old Lead Belt, Southeast Missouri, Jennifer Pace Witt
Downstream Dispersal Of Fine Tailings, Chat And Metals In Channel Sediment Of Big River, Old Lead Belt, Southeast Missouri, Jennifer Pace Witt
Graduate Theses/Dissertations
In St. François County, Missouri, compromised above-ground tailings piles and containment ponds from historical mining activities in the Old Lead Belt released considerable amounts of dolomitic, Pb- and Zn-contaminated waste sediments to the Big River, contributing to significant downstream floodplain and channel sediment contamination. Previous studies have documented the effects of heavy metals on Big River biota and water quality, as well as benthic habitat disruption resulting from the influx of small sediments. Few have considered the effects and future contamination risk of the coarse waste sediments (2-16 mm in diameter), locally called “chat”, which retain high Pb and Zn …
Coastal Landform Change Influences On Endangered Five-Lined Skink Distribution At Northwest Beach, Point Pelee National Park, Canada, Evan Fortushniok
Coastal Landform Change Influences On Endangered Five-Lined Skink Distribution At Northwest Beach, Point Pelee National Park, Canada, Evan Fortushniok
Theses and Dissertations (Comprehensive)
As park visitation increased to Point Pelee National Park up until its peak in 1963, the installation of infrastructure for the purpose of supporting the recreational interest grew with it. At Northwest Beach, large parking lots were built into the coastal landscape and by the 1970s large areas of sand dunes continued to be heavily impacted by the installation of visitor associated infrastructure. The infrastructure resulted in the stabilization of sand on the beach side of the parking lot, resulting in an artificially stabilized and heavily vegetated dune. Over the last few decades, the park slowly reduced the size and …
Paleoindian Response To Climate Change In The Northern Jornada Del Muerto, Christopher Wayne Merriman
Paleoindian Response To Climate Change In The Northern Jornada Del Muerto, Christopher Wayne Merriman
Anthropology ETDs
Human-environment interaction is a long-standing and productive line of inquiry that includes the study of cultural responses to climate change. However, demonstrating a causal relationship between climate change and the consequent culture change is rarely straightforward for numerous reasons. In this dissertation I develop an optimality model to predict how Paleoindians should have responded to changes in precipitation across the Late Pleistocene-Early Holocene. The water supply model (WSM) ranks water supplies much like the diet breadth model ranks food resources. To adjust the WSM for climate change, paleoclimate records from playas in the northern Jornada del Muerto were used in …
Analysis Of Titan's Fluvial Features Using Numerical Modeling, Jeshurun Horton
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 …
Fine Grained Delta Front Sediment Transport, Sarah Noel
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 …
The Morphodynamic Interaction Of River Deltas And Their Marshes, Kelly M. Sanks
The Morphodynamic Interaction Of River Deltas And Their Marshes, Kelly M. Sanks
Graduate Theses and Dissertations
Globally, many of the largest river deltas contain vast marsh platforms that are currently threatened due to a combination of anthropogenic alterations to rivers and increasing relative sea level rise. Restoration and management plans for river deltas depend on optimizing riverine sediment accumulation in marsh platforms. However, the accumulation of organic material in marsh platforms is often neglected in predictive models and the interaction of ecogeomorphic processes governing marsh accumulation with the physical processes governing river delta growth is poorly understood.
Herein, I investigate this complex relationship through a combination of field and experimental studies. I show that in coastal …
Speleogenesis In A Lens Of Metamorphosed Limestone And Ankerite: Ochtiná Aragonite Cave, Slovakia, Pavel Bella, Pavel Bosák, Petr Pruner, Helena Hercman, Katarína Pukanská, Karol Bartoš, Ľudovít Gaál, Dagmar Haviarová, Peter Tomčík, Šimon Kdýr
Speleogenesis In A Lens Of Metamorphosed Limestone And Ankerite: Ochtiná Aragonite Cave, Slovakia, Pavel Bella, Pavel Bosák, Petr Pruner, Helena Hercman, Katarína Pukanská, Karol Bartoš, Ľudovít Gaál, Dagmar Haviarová, Peter Tomčík, Šimon Kdýr
International Journal of Speleology
The Ochtiná Aragonite Cave (Western Carpathians) represents an unique natural phenomenon. It originated under particular lithological and hydrogeological conditions of the Ochtiná Karst in which several isolated lenses of Paleozoic crystalline limestone (marbles), partly metasomatically altered to ankerite, are enclosed by phyllites. Meteoric water seepage through non-carbonate rocks dissolved limestone and caused the oxidation of ankerite to Fe oxyhydroxides. Carbon dioxide produced during ankerite oxidation enhanced limestone dissolution. The maze cave consists of parallel fault-controlled linear passages and chambers interconnected by transverse horizontal passages. Phreatic and epiphreatic solution morphologies resulted from slowly moving or standing water. These include flat ceilings …
Silica Sinter And The Evolution Of Hot Springs In The Alvord/Pueblo Valleys, Southeast Oregon, Usa, Leslie Allen Mowbray, Michael L. Cummings
Silica Sinter And The Evolution Of Hot Springs In The Alvord/Pueblo Valleys, Southeast Oregon, Usa, Leslie Allen Mowbray, Michael L. Cummings
Geology Faculty Publications and Presentations
Hot springs in the Alvord/Pueblo valleys in southeastern Oregon are analogous to Basinand- Range hydrothermal systems where heat source and permeable pathways are met through crustal thinning. Silica sinter deposition at Mickey Springs, Alvord Valley, predates the late Pleistocene high stand of pluvial Lake Alvord. At Borax Lake, Pueblo Valley, sinter deposition occurred during the Holocene. This study examines the evolution of springs at Mickey Springs, where three morphologies of sinter are present: (1) basalt clasts surrounded by sinter in interbedded conglomerate and sandstone, (2) pool-edge and aprons of sinter surrounding depressions (12–32 m diameter), and (3) quaquaversal sinter mounds …
The Importance Of Lithologic Variability And Stratigraphic Architecture In The Development Of Eogenetic Karst Systems, Nicholas J. Soto-Kerans
The Importance Of Lithologic Variability And Stratigraphic Architecture In The Development Of Eogenetic Karst Systems, Nicholas J. Soto-Kerans
USF Tampa Graduate Theses and Dissertations
Integrative characterizations of karst systems on low-lying eogenetic carbonate platforms are rare and often limited to areas of direct observation where caves can be entered and explored. Because hydraulic properties of eogenetic limestones have been implicitly assumed to be homogeneous, classical models of carbonate island karst development stressed the importance of geochemical interfaces in controlling cave and vug development. These studies have explained the largest cavern systems as results of either 1) mixing dissolution at platform margins or 2) microbially-mediated dissolution processes at water tables.
New data from core descriptions and wireline logs obtained in 18 boreholes drilled in the …
Assessing Morphological Response And Vulnerability Of Barrier Islands To Extreme Storms In Northwest Florida, Jacob Adam
Assessing Morphological Response And Vulnerability Of Barrier Islands To Extreme Storms In Northwest Florida, Jacob Adam
USF Tampa Graduate Theses and Dissertations
Barrier islands shield the mainland coast from the effects of extreme storms such as increased wave energy and storm surge. During these events, however, barrier morphology can be altered by erosive forces. Thus, compromising the protection offered and leading to increased impact on the mainland. The St. Joseph Peninsula, located in the Northwest of the Gulf of Mexico, is one such barrier at threat from storm-induced erosion. Presented here is an assessment of morphology change induced by two major storms to impact the peninsula, Hurricanes Dennis 2005 and Michael 2018. These changes characterize the erosive/depositional patterns that can be expected …
Recharge Assessment In The Context Of Expanding Agricultural Activity: Urucuia Aquifer System, Western State Of Bahia, Brazil, Glauco Z.S. Eger, Gerson C. Silva Junior, Eduardo A.G. Marques, Bernardo R.C. Leão, Diana G.T.B. Da Rocha, Troy E. Gilmore, Luís G.H. Do Amaral, Juremá A.O. Silva, Christopher Neale
Recharge Assessment In The Context Of Expanding Agricultural Activity: Urucuia Aquifer System, Western State Of Bahia, Brazil, Glauco Z.S. Eger, Gerson C. Silva Junior, Eduardo A.G. Marques, Bernardo R.C. Leão, Diana G.T.B. Da Rocha, Troy E. Gilmore, Luís G.H. Do Amaral, Juremá A.O. Silva, Christopher Neale
Conservation and Survey Division: Faculty and Staff Publications
Groundwater recharge rate estimation is crucial to sustainable development of aquifers in intensely pumped regions, such as the Urucuia Aquifer System (UAS). A sedimentary aquifer in Western Bahia, Brazil, that underlies one of the major agricultural areas of the country where there has been major growth of irrigated areas. This study seeks to evaluate the recharge component of the water budget in the UAS area, based on three complementary techniques. The double-ring infiltrometer test was used to evaluate surface infiltration capacity, an important control on recharge. Water level data from wells (2011–2019 period, 19 wells) in the Brazilian Geological Survey’s …
Determination Of Sustainable Zones For Groundwater Abstraction From The Multi-Layered Aquifer System In The Bengal Basin, Bangladesh, Anwar Zahid, Muhammad Qumrul Hassan, Nazrul I. Khandaker
Determination Of Sustainable Zones For Groundwater Abstraction From The Multi-Layered Aquifer System In The Bengal Basin, Bangladesh, Anwar Zahid, Muhammad Qumrul Hassan, Nazrul I. Khandaker
Publications and Research
The use of deep groundwater (±300 m deep) is becoming an important issue in the Bengal Basin, due to both water quality problems and an acute shortage of available water in upper aquifers. In southeastern Bangladesh, multi-layered aquifer conditions exist with arsenic contamination at shallow depths, and high iron and brackish groundwater occurring mainly in the deeper layers. Many previous studies have offered explanations for the high concentrations of dissolved arsenic in groundwater - most of which proposed that the arsenic is derived from geo-genic sources and its release in groundwater is through natural processes, not the result of anthropogenic …
The Importance Of Monitoring To Assess The Impact Of Climate Change On Groundwater Resources In Bangladesh, Muhammad Qumrul Hassan, Anwar Zahid, Nazrul I. Khandaker
The Importance Of Monitoring To Assess The Impact Of Climate Change On Groundwater Resources In Bangladesh, Muhammad Qumrul Hassan, Anwar Zahid, Nazrul I. Khandaker
Publications and Research
Groundwater is the major source of fresh water across much of the world, but there has been very little study on the impacts of climate change on this precious and finite resource. Rising levels of greenhouse gases are likely to increase the global average surface temperature over the next 100 years, raise sea levels and reduce soil moisture. The amount of water stored in the soil is fundamentally important to agriculture and influences the rate of actual evaporation, groundwater recharge and runoff. Rising sea levels would cause the tidal saltwater wedge to intrude further upstream in rivers, with resulting changes …
Assessment Of The Impacts Of Urbanization On Land-Use And Land-Cover Changes Using Remote Sensing And Python At Gazipur District, Bangladesh, Atika Rahman Akji, Nowshin Ahsan Priyanka, Anwar Zahid, Muhammad Qumrul Hassan, Jowaher Raza, Nazrul I. Khandaker
Assessment Of The Impacts Of Urbanization On Land-Use And Land-Cover Changes Using Remote Sensing And Python At Gazipur District, Bangladesh, Atika Rahman Akji, Nowshin Ahsan Priyanka, Anwar Zahid, Muhammad Qumrul Hassan, Jowaher Raza, Nazrul I. Khandaker
Publications and Research
Urbanization has been the central demographic trend, not only in the Asia-Pacific region, but also for the entire world. Local geo-mapping is the vital tool for analyses of land-use and land-cover. This study attempts to classify land-use in unsupervised settings and create land-cover map by using open-source Landsat data integrated with GIS technologies and other ancillary resources. This work concentrates on Gazipur Sadar (an upazila or sub-district of the Gazipur District in central Bangladesh, part of the Dhaka Division) and Kaliakair, which are rapidly growing unplanned urban and industrial zones. The usage of python coding greatly assisted accomplishing the post-classification …
Geology And Hydrogeology Of Northeastern Nebraska: Geology, Water Management And Geological Hazards, Nebraska Geological Society Field Trip 2021, Robert F. Diffendal Jr., Sue Olafsen Lackey, Douglas R. Hallum
Geology And Hydrogeology Of Northeastern Nebraska: Geology, Water Management And Geological Hazards, Nebraska Geological Society Field Trip 2021, Robert F. Diffendal Jr., Sue Olafsen Lackey, Douglas R. Hallum
Conservation and Survey Division: Faculty and Staff Publications
The 2021 Nebraska Geological Society field trip will provide an overview of the geology and hydrogeology of northeast Nebraska, the groundwater quality and quantity issues unique to the region, water management issues and decision-making, and ongoing work relating to water quality and geologic (hydrostratigraphic) framework, along the lower Niobrara and Missouri rivers Between Spencer Dam and Homer Nebraska. This program will be comprised of an auto tour with multiple stops on Saturday October 16 through Monday October 18 as illustrated in Map 1. The tour will begin with an examination of the Spencer Dam site and several locations in and …
The Morphology And Evolution Of Transverse Aeolian Ridges On Mars, Timothy Paul Nagle-Mcnaughton
The Morphology And Evolution Of Transverse Aeolian Ridges On Mars, Timothy Paul Nagle-Mcnaughton
Earth and Planetary Sciences ETDs
Transverse aeolian ridges (TARs) are enigmatic and largely relict bedforms on the surface of Mars. TARs are sparsely distributed but common on Mars, but their history, preservation, and past role in the sediment cycle is not well understood. First described in 2003, and detailed extensively in 2008, our study of TARs has been narrowly focused in the last decade, with more and more research noting their presence, but little investigation of the features themselves. Recent work has mostly focused on identifying Terran analogues for TARs, but TARs remain largely a unique Martian feature. In this manuscript, I clarify and refine …
Molecular Genetic Analysis Of Stygobiotic Shrimps Of The Genus Xiphocaridinella (Crustacea: Decapoda: Atyidae) Reveals A Connection Between Distant Caves In Central Abkhazia, Southwestern Caucasus, Ivan Marin, Ilya Turbanov
Molecular Genetic Analysis Of Stygobiotic Shrimps Of The Genus Xiphocaridinella (Crustacea: Decapoda: Atyidae) Reveals A Connection Between Distant Caves In Central Abkhazia, Southwestern Caucasus, Ivan Marin, Ilya Turbanov
International Journal of Speleology
Based on the morpho-genetic study of stygobiotic shrimps from the genus Xiphocaridinella Sadowsky, 1930 (Crustacea: Decapoda: Atyidae), a hydrogeological connection of a number of distant caves in Central Abkhazia of the southwestern Caucasus is satisfied, which indicates the possibility of using biospeleological studies in some cases to identify karst hydrosystems together with traditional hydrogeological methods. Moreover, a new stygobiotic atyid shrimp from the genus Xiphocaridinella, X. kelasuri sp. n., is described based on morphology and analysis of mitochondrial cytochrome oxidase I DNA sequences from three distant caves. The new species is genetically divergent from relatives and phylogenetically related to …
Evaluating The Controls Of Neogene Exhumation In The Tropical Northern Andes (Colombia), Nicolas Perez Consuegra
Evaluating The Controls Of Neogene Exhumation In The Tropical Northern Andes (Colombia), Nicolas Perez Consuegra
Dissertations - ALL
Understanding how tectonic and climatic forces influence erosion and shape mountains is important to understand the evolution of the landscapes through earth's history. This dissertation aims to determine how do tectonic processes and climate variability interact to shape Earth's tropical mountains. In chapter 1, I studied the Eastern Cordillera of the Northern Andes, a mountain range located in Colombia in the tropics of South America. To obtain exhumation rates, I used thermochronology, which is a method that records—over timescales of millions of years—the rate at which rocks located at great depths within the Earth cool as they are transported to …
Ensemble Data Fitting For Bathymetric Models Informed By Nominal Data, Samantha Zambo
Ensemble Data Fitting For Bathymetric Models Informed By Nominal Data, Samantha Zambo
Dissertations
Due to the difficulty and expense of collecting bathymetric data, modeling is the primary tool to produce detailed maps of the ocean floor. Current modeling practices typically utilize only one interpolator; the industry standard is splines-in-tension.
In this dissertation we introduce a new nominal-informed ensemble interpolator designed to improve modeling accuracy in regions of sparse data. The method is guided by a priori domain knowledge provided by artificially intelligent classifiers. We recast such geomorphological classifications, such as ‘seamount’ or ‘ridge’, as nominal data which we utilize as foundational shapes in an expanded ordinary least squares regression-based algorithm. To our knowledge …
Diatoms Of The Intertidal Environments Of Willapa Bay, Washington, Usa As A Sea-Level Indicator, Isabel Hong, Benjamin P. Horton, Andrea D. Hawkes, Robert J. O.Donnell Iii, Jason S. Padgett, Tina Dura, Simon E. Engelhart
Diatoms Of The Intertidal Environments Of Willapa Bay, Washington, Usa As A Sea-Level Indicator, Isabel Hong, Benjamin P. Horton, Andrea D. Hawkes, Robert J. O.Donnell Iii, Jason S. Padgett, Tina Dura, Simon E. Engelhart
Geological Sciences Faculty Scholarship
An understanding of the modern relationship between diatom species and elevation is a prerequisite for using fossil diatoms to reconstruct relative sea level (RSL). We described modern diatom distributions from seven transects covering unvegetated subtidal environments to forested uplands from four tidal wetland sites (Smith Creek, Bone River, Niawiakum River, and Naselle River) of Willapa Bay, Washington, USA. We compared our diatom dataset (320 species from 104 samples) to a series of environmental variables (elevation, grain-size, total organic carbon (TOCSOM), and porewater salinity) using hierarchical clustering and ordination. While no single variable consistently explains variations in diatom assemblages …
Differences In Erosion Rates And Elevation Among Natural, Living And Hardened Shorelines In Mississippi, And Alabama, Brittany Juneau
Differences In Erosion Rates And Elevation Among Natural, Living And Hardened Shorelines In Mississippi, And Alabama, Brittany Juneau
Honors Theses
Shoreline erosion is a phenomenon that currently threatens both natural ecosystems and human settlements along the coast. With trends showing gradual sea level rise as a result of climate change, erosion is becoming an increasing threat to these communities. This research aims to provide more insight into the relationship between shoreline morphology and three shoreline protection techniques: natural marsh, living shoreline, and hardened structures. Six sites along the Alabama and Mississippi coast that had all three shoreline types were evaluated to determine what the average erosion rate and slope was for each shoreline. Erosion rates were calculated by image analysis …