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Articles 331 - 360 of 2252

Full-Text Articles in Geomorphology

Ductile And Brittle Deformation Of Slackwater Deposits In The Tucannon River Valley, Chelsi K. Howard Jun 2021

Ductile And Brittle Deformation Of Slackwater Deposits In The Tucannon River Valley, Chelsi K. Howard

Geosciences Student Work

The Tucannon River valley in eastern Washington is home to a number of ductile and brittle soft-sediment deformation. This project aims to look at ductile deformation by classifying and comparing styles of clastic dikes in the field and to look at brittle deformation by analyzing small faults in localized outcrops. Clastic dikes are sedimentary intrusions into other sedimentary strata. There are three main types of clastic dikes: injection, extrusion, and sugtrusion. In addition, two subcategories of clastic dikes are described as sheeted dikes and fault injection dikes. Ductile and brittle deformation occurs in “slackwater” deposits associated with margins of glacial …

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Four Decades Of Understanding Martian Geomorphology: Revisiting Baker's "The Geomorphology Of Mars", Anshuman Bhardwaj, Lydia Sam, Saeideh Gharehchahi Jun 2021

Four Decades Of Understanding Martian Geomorphology: Revisiting Baker's "The Geomorphology Of Mars", Anshuman Bhardwaj, Lydia Sam, Saeideh Gharehchahi

Research, Publications & Creative Work

Owing to multiple successful orbiter and rover missions in the past two and half decades, our understanding of the Martian atmosphere, terrain, and subsurface has continuously evolved. This prompts the need to revisit the first holistic review of Martian geomorphology based on useful images from Viking Mission orbiters, authored by Prof. Victor R. Baker. Several of the remote sensing-based interpretations and recommendations in Baker’s (1981) paper are as valid even today as they were four decades back. With an unprecedented focus on Mars exploration in the coming decades, it is important to briefly revisit the advances and prospects in Martian …

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Resolving A One-Year Ecesis Interval For Alaska Paper Birch: Dating A Rockfall Event, Wishbone Hill, Southcentral Alaska, Riley E. Whitney, Alexander K. Stewart, Trent D. Hubbard, Anabella S. Kowalski, Oscar A. Wilkerson May 2021

Resolving A One-Year Ecesis Interval For Alaska Paper Birch: Dating A Rockfall Event, Wishbone Hill, Southcentral Alaska, Riley E. Whitney, Alexander K. Stewart, Trent D. Hubbard, Anabella S. Kowalski, Oscar A. Wilkerson

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Numerous large boulders at the base of Wishbone Hill, northeast of Anchorage, Alaska, suggest a historic rockfall event and potential for future surface instability, putting lives and property at risk. The source of the rockfall-boulders is an exposed syncline with a cliff face composed of conglomerate. The age of trees growing atop boulders provides a minimum exposure-age of those boulders and, thus, the rockfall event. To determine when the rockfall occurred, we dated trees growing atop the boulders using tree-ring samples collected from 30 Alaska paper birch trees. After mounting and polishing, each tree-ring sample was dot-counted, and tree-ring widths …

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Mineralogy Of Aeolian Deposits In Gale Crater, Mars: The Bagnold Dunes To Glen Torridon, Eleanor Moreland May 2021

Mineralogy Of Aeolian Deposits In Gale Crater, Mars: The Bagnold Dunes To Glen Torridon, Eleanor Moreland

Senior Honors Papers / Undergraduate Theses

We select four sand deposits along the traverse of the Curiosity rover to evaluate the spatial distribution of mineralogy and grain size. While extensive work has focused on characterizing the Bagnold Dunes in-situ and from orbit, less attention has been given to deposits south of the Vera Rubin Ridge (VRR). Overall, our results illustrate a compositional dichotomy among aeolian deposits, separated by the VRR. Initial investigations of hyperspectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show differences in the long wavelength spectral features and absolute reflectance measurements for the deposit south of the Bagnold Dunes. The southern …

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Characterization Of Landslide Processes From Radar Remote Sensing And Hydromechanical Modeling, Yuankun Xu May 2021

Characterization Of Landslide Processes From Radar Remote Sensing And Hydromechanical Modeling, Yuankun Xu

Earth Sciences Theses and Dissertations

Landsides are a natural geomorphic process yet a dangerous hazard which annually causes thousands of casualties and billions of property loss in a global scale. Understanding landslide motion kinematics from early initiation to final deposition is critical for monitoring, assessing, and forecasting landslide movement in order to mitigate their hazards. Landslides occur under diverse environmental settings and appear in variable types; however, all types of landslides can be mechanically attributed to shearing failure at the basal surface due to stress regime shift contributed by internal and/or external forcing. Typical internal factors include soil/rock weathering, whereas typical external triggering forces encompass …

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Late Amazonian Wind Regimes And Landscape Evolution In Northern Meridiani Planum, Mars, Thomas Stritch May 2021

Late Amazonian Wind Regimes And Landscape Evolution In Northern Meridiani Planum, Mars, Thomas Stritch

Geology: Student Scholarship & Creative Works

Aeolian process have dominated the lower latitudes of Mars for billions of years. Aeolian landforms can act as records of current and past climates and landscape evolution processes. The etched deposits of Meridiani Planum, a vast suite of layered bedrock extending from southwest Arabia Terra to Schiaparelli crater, have long been noted to have been eroded by aeolian processes. However, little detailed work on the aeolian landforms of Meridiani Planum beyond the Opportunity rover landing site has been done. In this study, I examine wind streaks, aeolian bedforms (including dunes and large ripples), and yardangs in a valley about 370 …

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Linking Human Activities To Water Quality In Coastal New England: Past And Present, Amelia Hurst May 2021

Linking Human Activities To Water Quality In Coastal New England: Past And Present, Amelia Hurst

University Scholar Projects

This project examines the timing and effect of direct and indirect anthropogenic and natural influences on the marine environment in embayments in southern New England over the past decades to century timescale. We investigated the effects of human land use from colonial through post-industrial times, determined baseline conditions and natural climatic variability, and analyzed the response of marine ecosystems to specific local management actions aimed to improve water quality. A coastal sediment core was taken in Mumford Cove, CT and was analyzed downcore for eutrophication markers (C: N, %C, %N, d15N, d13C) and metals (Hg, Pb, …

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The Role Of Elevation As A Control On Salt Marsh-Upland Ecotones Along The Mississippi Gulf Coast, Carlton P. Anderson May 2021

The Role Of Elevation As A Control On Salt Marsh-Upland Ecotones Along The Mississippi Gulf Coast, Carlton P. Anderson

Dissertations

Salt marshes are critical ecological gems that serve as habitat for many specialized species of flora and fauna, while providing a natural buffer to human populations from tropical cyclone impacts. However, rises growth of coastal populations has led to greater strain on the natural services these ecosystems provide. To better understand and project the future of coastal evolution, the physical, mechanical, and biological feedbacks between the natural and human coupled systems need to be more defined and thoroughly understood. Human encroachment towards naturally retreating shorelines will lead to coastal communities being more susceptible to nuisance tidal flooding and minor tropical …

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Assessing Soil-Related Terroir Factors In Sunnyslope District Vineyards Of Southwest Idaho, Rachael Nicole Haggen May 2021

Assessing Soil-Related Terroir Factors In Sunnyslope District Vineyards Of Southwest Idaho, Rachael Nicole Haggen

Boise State University Theses and Dissertations

Terroir is the set of factors including climate, soil, and management practices that influence the character of a wine. Of these factors, soil texture and chemistry is a major determinant in wine grape quality (van Leeuwen et al., 2009). Understanding the characteristics of the soil is key to making decisions that support the production of the highest possible quality grapes from the resources available. Few studies have been conducted in the Snake River Valley AVA (SRVAVA). This study seeks to build upon the data already available and provide analysis of vineyard-scale terroir in a leading grape growing district of the …

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Joint Spacing In The Caples Lake Granodiorite Of The Sierra Nevada Batholith In Eldorado National Forest, California: A Comparative Analysis Of Joint Sets And Data Resolution, Jimmy Wood May 2021

Joint Spacing In The Caples Lake Granodiorite Of The Sierra Nevada Batholith In Eldorado National Forest, California: A Comparative Analysis Of Joint Sets And Data Resolution, Jimmy Wood

Theses/Capstones/Creative Projects

Joints are the most common deformation structure in the Earth’s upper crust and exert a significant influence on structural stability, landscape morphology, and fluid flow . Therefore, a greater understanding of fracture parameters (e.g., length, aperture, etc.) allows us to more accurately predict their presence, persistence, and prevalence, in the subsurface . We study the fracture spacing of two sub-orthogonal joint sets—66 NE-246 SW and 330 NW-150 SE—in the Caples Lake granodiorite of the Sierra Nevada Batholith, California. Specifically, we investigate 1) their spacing distributions with a keen interest in power-law (fractal) spacing, 2) distribution comparisons between master and cross …

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Small-Scale Resuspension And Redistribution Of Surface Sediments In The Northeast Gulf Of Mexico, Austin Harris May 2021

Small-Scale Resuspension And Redistribution Of Surface Sediments In The Northeast Gulf Of Mexico, Austin Harris

Master's Theses

Following the release of ~4.9 million barrels of oil into the Gulf of Mexico from the Macondo wellhead, a vast area of the seafloor contained recently deposited marine sediments contaminated by the oil spill. The initial deposition of these contaminated marine sediments was likely not the end of the journey for the particles. Downslope gravitational processes and events of increased current speed in the deep ocean setting can result in recently deposited sediments to resuspend and be moved laterally with the current flow, increasing the area effected by the oil spill. Erosion experiments performed in a closed-loop resuspension flume were …

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Effects Of The Triassic-Jurassic Central Atlantic Magmatic Event Recorded In Continental Strata In Western Pangea: The Δ13c Record Of Warner Valley & Zion National Park, Dennis Mmasa May 2021

Effects Of The Triassic-Jurassic Central Atlantic Magmatic Event Recorded In Continental Strata In Western Pangea: The Δ13c Record Of Warner Valley & Zion National Park, Dennis Mmasa

Graduate Theses and Dissertations

The Triassic is a period of abrupt climate change bracketed by mass extinctions including one driven by the eruption of the Central Atlantic Magmatic Province (CAMP) in the Late Triassic. The Moenave Formation (MF) of Utah and Arizona is ideal to investigate effects of the CAMP on continental strata distal to the eruptive center. This study focuses on the C-isotopic composition of bulk carbonate C from two localities, Blacks Canyon, Zion National Park, UT and Olsen Canyon within Warner Valley, UT. The data collected was used to document a chemostratigraphic record to compare to globally established records and bulk organic …

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Biis: The Last British Ice Sheet, A Review Of The Most Recent Major Glaciation Of Great Britain And Ireland, Benediktas Gaskevicius Apr 2021

Biis: The Last British Ice Sheet, A Review Of The Most Recent Major Glaciation Of Great Britain And Ireland, Benediktas Gaskevicius

Honors College Theses

The British Irish Ice Sheet was a substantial ice mass covering the British Isles during the most recent glaciation that ended around 11,700 years ago. Oftentimes referred to as the BIIS, it is subdivided into two sections, a western and eastern side that covered Great Britain and Ireland, with the Irish basin in the middle. Some notable areas of study around Great Britain and Ireland include the ’Bizzle’ in Northern England, which was transformed by the effects of the eastern margin of the BIIS, the Carstair Kames in Scotland, a locality known internationally for its esker system, The Minch region …

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069— Geomorphic Characteristics Of Canadice Lake, Ny, Watersheds And The Anthropogenic Effects On Watershed Output And Sensitivity, Carla Crampton Apr 2021

069— Geomorphic Characteristics Of Canadice Lake, Ny, Watersheds And The Anthropogenic Effects On Watershed Output And Sensitivity, Carla Crampton

GREAT Day Posters

Land use and size of watershed catchment areas affects the overall health and water quality of Canadice Lake. Methods in ArcGIS Pro were used for high resolution imagery and topography data to analyze the geomorphology of watersheds at Canadice Lake. Watersheds were mapped using ArcGIS Hydrology tools by constructing flow direction and accumulation grids. In each individual watershed, total area of the watershed, area of residential and agricultural land use, and total length of roads was determined to evaluate which watersheds are most sensitive to human impact and which watersheds are likely to contribute the highest flow discharge and sediment …

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205— Revisiting The Geologic History Of The Pathfinder Landing Site At Ares Vallis, Mars, Andrew Agent Apr 2021

205— Revisiting The Geologic History Of The Pathfinder Landing Site At Ares Vallis, Mars, Andrew Agent

GREAT Day Posters

Before NASA sent the Pathfinder lander and Sojourner rover to the mouth of Ares Vallis in 1997, they anticipated the discovery of Hesperian-age (3.6 Ga-3.0 Ga) sediments deposited from catastrophic outflows. When pictures came back, the rocks they discovered were large, boulder-size, angular, and were largely inconsistent with transport by large floods. The origin of the deposits at the Pathfinder landing site remains controversial. This study aims to constrain the surface geology of the Pathfinder landing site using new high-resolution imagery and crater statistics. Context Camera (CTX) images along with High-Resolution Imaging Experiment (HiRISE) images were used to map surface …

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328— Watershed Analysis Of The Eberswalde Delta (Early Hesperian), Mars, Jason Mueller Apr 2021

328— Watershed Analysis Of The Eberswalde Delta (Early Hesperian), Mars, Jason Mueller

GREAT Day Posters

The Eberswalde Delta is an impressive Martian fluvial-deltaic system. It is fed by an Earth-like dendritic river system that indicates past precipitation. This study is designed to quantify controls on network morphometry and its past extent using Esri ArcMap. Upstream contributing area (km2), elevation (m), depth (m), width (m), W/D ratio, and slope (-m/m), were calculated and graphed by stream order and long profiles. Width/depth increased with distance downstream but fluctuated in the fifth-order channel that was convex with knickpoints. This implied the system was youthful. The fourth-order stream was concave and in a sedimentary sub-basin. This sub-basin may have …

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Glacial Geology Of Readfield Maine, Bryer Carlson Apr 2021

Glacial Geology Of Readfield Maine, Bryer Carlson

Michael D. Wilson Symposium

This poster explores the glacial geology in the town of Readfield Maine. With the use of GPR (ground penetrating radar), LiDar imaging and the State's surficial geology maps, evidence for a specific glacial feature called an "esker" was sought out and collected.

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Climatic Controls On The Kinematics Of The Hooskanaden Landslide, Curry County, Oregon, Kara Kingen Apr 2021

Climatic Controls On The Kinematics Of The Hooskanaden Landslide, Curry County, Oregon, Kara Kingen

Dissertations and Theses

Slow-moving earthflows represent major sources of sediment transport and erosion and are problematic for the management of critical infrastructure. The Hooskanaden Landslide -- a slow-moving earthflow on the southwest coast of Oregon -- crosses US Highway 101 and has been a site of continued interest to the Oregon Department of Transportation (ODOT) due to the weak lithology, erosive environment, and recurrent surge behavior (every ~15 years). Past surges, including the most recent (2019), have occurred during the winter, suggesting that velocity changes are predominantly controlled by climatic inputs. To examine the response of the Hooskanaden Landslide to seasonal and other …

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Serial Interaction Of Primitive Magmas With Felsic And Mafic Crust Recorded By Gabbroic Dikes From The Antarctic Extension Of The Karoo Large Igneous Province, Jussi S. Heinonen, Arto V. Luttinen, Frank J. Spera, Saku K. Vuori, Wendy A. Bohrson Mar 2021

Serial Interaction Of Primitive Magmas With Felsic And Mafic Crust Recorded By Gabbroic Dikes From The Antarctic Extension Of The Karoo Large Igneous Province, Jussi S. Heinonen, Arto V. Luttinen, Frank J. Spera, Saku K. Vuori, Wendy A. Bohrson

Geological Sciences Faculty Scholarship

Two subvertical gabbroic dikes with widths of ~ 350 m (East-Muren) and ≥ 500 m (West-Muren) crosscut continental flood basalts in the Antarctic extension of the ~ 180 Ma Karoo large igneous province (LIP) in Vestfjella, western Dronning Maud Land. The dikes exhibit unusual geochemical profiles; most significantly, initial (at 180 Ma) εNd values increase from the dike interiors towards the hornfelsed wallrock basalts (from − 15.3 to − 7.8 in East-Muren and more gradually from − 9.0 to − 5.5 in West-Muren). In this study, we utilize models of partial melting and energy-constrained assimilation‒fractional crystallization in deciphering the …

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Hydro-Morphodynamics Of Sandy Coastal Embayments, Shamim Murshid Mar 2021

Hydro-Morphodynamics Of Sandy Coastal Embayments, Shamim Murshid

LSU Doctoral Dissertations

This dissertation investigates the hydro-morphodynamics of two major components of a sandy coastal environment: tidal inlets and embayment shorelines. In the first study, I focused on the evolution of inlet geometry by compiling and analyzing a database with 226 inlets worldwide with a special attention given to their width to depth ratio (or aspect ratio). I found that the aspect ratio has a weak dependency on tidal range and wave height, and they lie in different ranges for three types of tidal inlets: engineered, natural single-thread, and natural compound. I also developed a 2D hydro-morphodynamic model of an idealized barrier-inlet …

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Evaluation Of Manual And Semi-Automated Deep-Seated Landslide Inventory Processes: Willapa Hills, Washington, Tiffany E. Justice Mar 2021

Evaluation Of Manual And Semi-Automated Deep-Seated Landslide Inventory Processes: Willapa Hills, Washington, Tiffany E. Justice

Dissertations and Theses

Recent advances in remote sensing data and technology have allowed for computational models to be designed that successfully extract landforms from the landscape. The goal of this work is to create one such semi-automated model to extract deep-seated landslides located in complex geomorphic terrain. This is accomplished using geographic object-based image analysis (GEOBIA) techniques, considered by leaders in the field of image analysis to have an advantage over traditional automated classification methods. GEOBIA methods can mimic human visual interpretation by including more characteristic features used to assess the relationship between image data and the ground surface such as color reflectance …

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Rock Glen Wildlife Area: A Landscape History, Gerry Steinauer, Robert Diffendal Jr. Mar 2021

Rock Glen Wildlife Area: A Landscape History, Gerry Steinauer, Robert Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Nestled in the hills of southern Jefferson County, Rock Glen Wildlife Management Area, as its name implies, is a rocky land shaped by ancient geological forces, among them, meandering tropical rivers and grinding glacial ice. Euro-American settlers in the region arrived to a picturesque scene: rolling hills cloaked in tallgrass prairie fingered by glens, narrow valleys and canyons, filled with sprawling bur oaks. Too rocky to plow, southern Jefferson County has survived as an island of prairie amidst a sea of cropland. Settlement was not kind to the land. Fire suppression allowed eastern red cedars and other trees to spread, …

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Boulders As A Lithologic Control On River And Landscape Response To Tectonic Forcing At The Mendocino Triple Junction, Charles Shobe, Georgina Bennett, Gregory Tucker, Kevin Roback, Scott Miller, Joshua Roering Mar 2021

Boulders As A Lithologic Control On River And Landscape Response To Tectonic Forcing At The Mendocino Triple Junction, Charles Shobe, Georgina Bennett, Gregory Tucker, Kevin Roback, Scott Miller, Joshua Roering

Faculty & Staff Scholarship

Constraining Earth’s sediment mass balance over geologic time requires a quantitative understanding of how landscapes respond to transient tectonic perturbations. However, the mechanisms by which bedrock lithology governs landscape response remain poorly understood. Rock type influences the size of sediment delivered to river channels, which controls how efficiently rivers respond to tectonic forcing. The Mendocino triple junction region of northern California, USA, is one landscape in which large boulders, delivered by hillslope failures to channels, may alter the pace of landscape response to a pulse of rock uplift. Boulders frequently delivered by earthflows in one lithology, the Franciscan mélange, have …

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On The Genesis Of Aluminum-Rich Speleothems In A Granite Cave Of Nw Spain, Jorge Sanjurjo-Sanchez, Carlos Arce Chamorro, Juan Ramón Vidal Romaní, Marcos Vaqueiro-Rodríguez, Victor Barrientos, Joeri Kaal Feb 2021

On The Genesis Of Aluminum-Rich Speleothems In A Granite Cave Of Nw Spain, Jorge Sanjurjo-Sanchez, Carlos Arce Chamorro, Juan Ramón Vidal Romaní, Marcos Vaqueiro-Rodríguez, Victor Barrientos, Joeri Kaal

International Journal of Speleology

Granite massifs often contain caves, with dimensions ranging from a few meters up to 1,000 m, also referred to as pseudokarst. The speleothems in such caves are mostly composed of either Si-rich (commonly opal-A) or Al-rich authigenic mineraloids. Whereas the formation and geochemical composition of opal-A biospeleothems have been studied and are fairly well understood, knowledge on the Al-rich analogues is scarce. This work reports for the first time a study on the composition, accretion process, age and growth rate of an Al-rich speleothem type flowstone from the A Trapa Cave System (Galicia, NW Spain), developed in a granite cave. …

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Nebraska Statewide Groundwater-Level Monitoring Report 2020, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel Feb 2021

Nebraska Statewide Groundwater-Level Monitoring Report 2020, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel

Conservation and Survey Division: Faculty and Staff Publications

The term “groundwater” has come to be all but synonymous with Nebraska. Nearly three-quarters of the total volume of the High Plains Aquifer lies beneath the state. Groundwater maintains our streams, our ecosystems, our people, and our vitally important agricultural economy. Nebraska’s total groundwater resource is vast, yet it is also vulnerable to natural and anthropogenic changes, necessitating a long-term commitment to wise management through informed decision-making. Monitoring, studying, and reporting form the essential basis for such management and, ultimately, for meeting the myriad challenges presented by change.

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Coastal Watershed Monitoring And Management: Geomorphology, Geochemistry, And Hydrologic Modeling Of Los Peñasquitos Creek, Ca, Ravleen Khalsa-Basra Jan 2021

Coastal Watershed Monitoring And Management: Geomorphology, Geochemistry, And Hydrologic Modeling Of Los Peñasquitos Creek, Ca, Ravleen Khalsa-Basra

Theses

Rivers in semi-arid climates are directly influenced by local geographic and hydrologic conditions and impacted by modifications to hydrology via urbanization. Changes can influence erosion, morphology, habitat sustainability, and watershed health. In highly urbanized southern California coastal regions, these rare open spaces provide vital ecosystem services. Los Peñasquitos Creek in San Diego County is one such watershed. Using stream surveying and laboratory methods we quantified channel characteristics, grain size distribution, total metal concentration [M], organic carbon (%OC), and phosphate to longitudinally characterize the creek for improved management. Results identified three distinct reaches in the watershed (upper, middle, lower). Downstream, depth …

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Amount And Depositional Fate Of Carbon Mobilized By Landsliding In Se Alaska, Bryce Alois Vascik Jan 2021

Amount And Depositional Fate Of Carbon Mobilized By Landsliding In Se Alaska, Bryce Alois Vascik

Dissertations and Theses

Forest disturbances in the form of landslides mobilize carbon (C) sequestered in vegetation and soils. The mobilized C has two basic depositional fates, deposition onto hillslopes or into water, which sequester C from and release C to the atmosphere at different time scales. The C-dense old-growth temperate forests of SE Alaska are a unique location to quantify the C mobilization rate by frequent landslide events. In this study, we estimate the amount of C mobilized by debris flows over historic time scales by combining a landslide inventory with maps of modeled biomass and soil carbon. We then infer depositional fate …

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New Hampshire Continental Shelf Geophysical Database: 2002-2005 Jeffreys Ledge Field Campaign – Seafloor Photographs And Sediment Data, Larry G. Ward, Raymond E. Grizzle, Rachel C. Morrison Jan 2021

New Hampshire Continental Shelf Geophysical Database: 2002-2005 Jeffreys Ledge Field Campaign – Seafloor Photographs And Sediment Data, Larry G. Ward, Raymond E. Grizzle, Rachel C. Morrison

Data Catalog

Jeffreys Ledge is a major physiographic feature in the western Gulf of Maine (WGOM) located ~50 km off the coast of New Hampshire, although coming within ~10 km of shore by Cape Ann, Massachusetts. Jeffreys Ledge rises up as much as ~150 m from the seafloor of the adjacent basins (i.e., Scantum Basin or Wilkinson Basin) to depths less than 50 m on the ridge surface. The ridge extends over 100 km along its north-northeast to south-southwest axes while generally only being 5 to 10 km in width (~20 km maximum). Jeffreys Ledge and the surrounding region, like many features …

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Bed Particle Displacements And Morphological Development In A Wandering Gravel-Bed River, Ryan Mcqueen, Peter Ashmore, T Millard, N Goeller Jan 2021

Bed Particle Displacements And Morphological Development In A Wandering Gravel-Bed River, Ryan Mcqueen, Peter Ashmore, T Millard, N Goeller

Geography & Environment Publications

Bed particles were tracked using passive integrated transponder tags in a wandering reach of the San Juan River, British Columbia, Canada, to assess particle movement around three major bars in the river. In-channel topographic changes were monitored through repeat LiDAR surveys during this period and used in concert with the tracer data set to assess the relationship between particle displacements and changes in channel morphology, specifically, the development and re-working of bars. This has direct implications for virtual velocity and morphologic based estimates of bedload flux, which rely on accurate estimates of the variability and magnitude of particle path lengths …

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Soils And Paleosols, Daniel R. Muhs Jan 2021

Soils And Paleosols, Daniel R. Muhs

United States Geological Survey: Publications

This article reviews the nature of modern and ancient soils. Soils are naturally occurring bodies that mantle most of the land surface of the Earth. They are found on virtually every part of the Earth’s land surface, other than areas covered by water bodies (lakes and rivers), glacial ice, or steep slopes in mountainous terrain. Soils occur at the interface of the geosphere, hydrosphere, biosphere, and atmosphere and are the medium of growth for much of the Earth’s plant and animal life. The study of soils as naturally occurring bodies on the Earth’s surface is called pedology (in contrast to …

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