Geomorphology Commons^™

Documenting The Origin Of Compositional Diversity Of Subduction Zone Magmatism, Alicudi, Aeolian Arc (Southern Tyrrhenian Sea, Italy) Using In Situ Plagioclase Data, Rachel Hunt

All Master's Theses

Processes that generate magma compositional diversity are important to document because composition affects degree of explosivity, which impacts hazard mitigation. Magnesium to silicon rich magmas are produced by processes such as magma recharge, assimilation, and fractional crystallization (RAFC) that occur in subvolcanic magma chamber(s). This study evaluates how magma chamber processes contribute to compositional diversity at Alicudi Volcano, Italy. Analytical and petrographic data from ten samples that span the subaerial history include whole rock major and trace elements and strontium/neodymium isotopes, and plagioclase textural types, major and trace elements, and strontium isotopes; numerical modeling was also conducted. Integration of these …

Documenting Magma Evolution Of The Fossa Delle Felci (Salina Island, South Tyrrhenian Sea) By Integrating In Situ Plagioclase Data With Quantitative Modeling, Aaron Mayfield

All Master's Theses

Compositional diversity occurs via processes dominated by recharge, assimilation and fractional crystallization (RAFC), quantification of which can provide insights into eruption catalysts, and therefore assist in hazard mitigation. This study evaluates the relative roles of RAFC processes in Fossa delle Felci (Salina Island, Italy) magmas, which span the basalt to dacite range (52-65 wt% SiO2). Integration of petrographic, whole rock, and in situ plagioclase data with quantitative magma chamber models suggests differentiation dominated by fractional crystallization and magma recharge/mixing in reservoirs located at different crustal levels. At ~12 km depth, magma evolved through crystallization of a pyroxene dominated assemblage; plagioclase …

Petrogenetic Relationship Of The Postcaldera Eruptions Of Mount Mazama, Crater Lake, Oregon; Evolution Of A Sub-Volcanic Magma Chamber Following A Large Silicic Eruption, Michelle Leanna Tebbe

All Master's Theses

Mount Mazama is the volcanic edifice that cataclysmically erupted ~503 km of relatively homogeneous rhyodacite lava ~ 7,700 years ago, forming the caldera known as Crater Lake. Within a few hundred years, andesitic eruptions built three distinct volcanic edifices on the floor of Crater Lake; ~ 3000 years later, rhyodacite eruptions formed a dome (Bacon et al., 2002). How magmatic systems evolve following a shallow, relatively large silicic eruption is the focus of this study. In situ geochemical analysis coupled with high-resolution textural images of plagioclase crystals in the four postcaldera volcanic edifices were used to identify distinct crystal populations …

Documenting Magnatic Processes At Filicudi Island, Aeolian Arc, Italy: Integrating Quantitative Modeling And Plagioclase Textural And In Situ Compositional Data, Michelle Harris

All Master's Theses

Documenting the physiochemical processes that influence magma composition is critical for forecasting eruption styles and managing volcanic hazards. Compositional diversity of magmas develops through recharge, assimilation, and fractional crystallization (RAFC) within subvolcanic magma reservoirs. Integration of MELTS modeling, whole rock, plagioclase textural and in situ elemental and isotopic data from Filicudi Island, Italy allow documentation of the roles and relative chronology that RAFC played in the magmatic evolution and elucidates aspects of the magma plumbing system structure.

Results indicate a polybaric magma plumbing system with deeper (3.5-4 kilobars) and shallower (0.5-1.2 kilobars) storage regions. Within the deeper system, FC acted …

Natural And Anthropogenic Influences On The Morphodynamics Of Sandy And Mixed Sand And Gravel Beaches, Tiffany Roberts

USF Tampa Graduate Theses and Dissertations

Beaches and coastal environments are dynamic, constantly shaped and reshaped by natural processes and anthropogenic modifications. The morphodynamics and influence of natural and anthropogenic factors of two different coasts at various temporal and spatial scales are discussed.

To quantify the performance of several beach nourishment projects at annual temporal and kilometer spatial scales on three adjacent microtidal low-wave energy barrier islands in west-central Florida, a total of 5,200 beach and nearshore-profiles spaced at 300 m were surveyed monthly to bi-monthly from 2006-2010. Beach nourishment performance is most significantly influenced by the interruption of longshore sediment transport by complex tidal-inlet processes. …

Guidebook To The Geology Of The Platte River Valley Between Duncan And Schuyler, Nebraska, P.R. Hanson, Robert Matthew Joeckel, Aaron R. Young, Dana Divine, Jesse T. Korus Dr.

Conservation and Survey Division: Faculty and Staff Publications

The Platte River is considered to be a classic example of a braided stream, that is, a comparatively shallow stream with a high width:depth ratio.

Grain Size Distribution With Geomorphology On Gypsum Dunes In The White Sands Erg, White Sands National Monument, New Mexico, Slade Jones

Open Access Theses & Dissertations

In order to examine grain size distribution over dunes at the White Sands dune field, 1214 geolocated surficial samples were collected and analyzed by laser diffraction. Local variations in dunes such as neighboring interdune types and the presence of vegetation, deflation features, and granule ripples on the dunes were noted. This study indicates that recrystallization of gypsum and the generation of fresh sediments is occurring in significant quantities within interdunes, providing both high and low anomalies in grain size distribution through much of the central portion of the dune field. Other local variations as previously mentioned such as scour surfaces …

Nebraska Statewide Groundwater-Level Monitoring Report 2011, Jesse T. Korus Dr., Mark E. Burbach, Leslie M. Howard

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Three Geologic Cross Sections Across Portions Of Eastern Nebraska Showing Quaternary Lithologic Units And Stratigraphy Of Uppermost Bedrock, Jesse T. Korus, Dana Divine, P. R. Hanson, J. S. Dillon

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Nebraska Statewide Groundwater-Level Monitoring Report 2012, A. R. Young, M. E. Burbach, J. T. Korus, L. M. Howard

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Late Pleistocene And Holocene Aged Glacial And Climatic Reconstructions In The Goat Rocks Wilderness, Washington, United States, Joshua Andrews Heard

Dissertations and Theses

Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium line altitude …

Collisional Reactivation Of Rift Margin Fracture Zones, Taiwan And The Taconic Allochthon, David C. Mirakian

Master's Theses

Chapter I. Transverse Topographic Development due to the Reactivation of a Partially-Subducted Fracture Zone: The Southwest Hsüehshan Range, Central Taiwan

Abstract — The southwest flank of the Hsüehshan Range is defined by a topographic break which cuts across regionally mapped structures in central Taiwan. The mountain front trends ~345°, slightly oblique to the Sanyi-Puli seismic zone which has been previously interpreted as a reactivated continental margin fracture zone. Structural data collected along the length of the topographic break reveal two populations of cross-cutting faults with distinct fault-zone materials and a series of southwest-plunging folds. Paleostress axes were reconstructed using the …

Understanding Uplift Of The Ethiopian Plateau From Longitudinal Profile Analysis Of The Blue Nile Drainage System, Prabhat Chandra Neupane

LSU New Orleans Theses and Dissertations

The Ethiopian Plateau is one of the few tectonically-active regions on Earth that is situated in continental rift zones. About 1.6 km deep gorge of the Nile was carved by the Blue Nile River on the Ethiopian Plateau, as the plateau has been experiencing continuous uplift and exhumation in the Cenozoic. Here, we used quantitative analysis of longitudinal rive-profile forms and parameters (knickpoint and normalized steepness-index k_sn) of the Blue Nile tributaries to tease out regional tectonic signals.

244 knickpoints were examined in the tributaries, majority (>80%) of which are unassociated with lithology or geological structures. Knickpoint …

Land Systems Of The Kimberley Region, Western Australia, A L. Payne, N Schoknecht

Technical Bulletins

The Land Systems of the Kimberley Region Report describes and maps the landscapes, soils and vegetation of the Kimberley region. This report is a consolidation of surveys carried out by different organisations, across different areas of the Kimberley, since the 1940s. The Kimberley region, as defined in this bulletin, covers 330 070km². The report categorises the Kimberley region into 111 land systems. Under each land system, the report identifies the vulnerabilities of those areas, and provides recommendations on how to achieve sustainable use. The report also publishes pasture types for the entire region and the grazing potential for each pasture, …

Relating Land Cover And Channel Morphology To Stream Flow Function In The Lower Pee Dee Watershed, South Carolina, Zachary Smoot

All Theses

The South Carolina Pee Dee Project (SCPDP) aims to develop a method for the determination of Minimum Allowable Flows (MAFs) in streams in the Pee Dee region. This study is a portion of the larger SCPDP, focusing primarily upon analyses of geomorphic and hydrologic processes, as well as landscape and habitat analyses. Specific objectives include: 1) To distinguish the effect of various land cover classes and scales of analyses on components of stream flow function; 2) To determine trends in hydraulic geometry (regional curves) for the SCPDP region; and 3) To determine what measures of stream flow function, stream geomorphology, …

Magma Chamber Processes At Mutnovsky Volcano, Russia, Kelly L. Robertson

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation is composed of two manuscripts about the evolution of Mutnovsky Volcano in Kamchatka, Russia. Mutnovsky has been active for the past approximately 80,000 years, during which there was the formation and subsequent eruption of four major stratocones. These four eruptive centers, named Mutnovsky I, II, III, and IV from oldest to youngest, have a range of erupted product compositions from basalt to dacite. The first major goal of this project was to investigate the melt source for Mutnovsky. Whole rock trace element and Nd, Sr, and Pb isotopic data were used to determine that the melt source was …

Post-Fire Near-Surface Runoff From Small-Scale Rainfall Simulations, Santa Cruz Mountains, Michael Founds

Natural Resources Management and Environmental Sciences

The influence of environmental variables on the runoff response to a fire is poorly understood. Small-scale rainfall simulation was used to study the factors impacting near-surface runoff following the Lockheed Fire, which occurred on August 12, 2009. A variable speed rainfall simulator was used to rain on 15 different test plots at an average rate of 50mmh^-1. Variables of burn severity, time following the fire, soil parent material, vegetation type, and presence of a duff layer were all analyzed using the ratio of runoff to rainfall. The difference in-between burned sites and similar control sites were 19±6%. Only …

Geogram 2011, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Mapping Of Unstable And Potentially Unstable Slopes In Sogne Og Fjordane, Reginald L. Hermanns, Luzia Fischer, Thierry Oppikofer, M. Bøhme, John F. Dehls, H. Henriksen, Adam M. Booth, R. Eilertsen, O. Longva, Trond Eiken

Geology Faculty Publications and Presentations

For the past three years NGU has worked on 25 unstable and potentially unstable rock slopes in Sogn og Fjordane. In addition Fjærlandsfjord, Hyenfjord and Årdalsvatnet were systematically mapped for deposits of prehistoric and historic rock slope failures onshore and with help of a bathymetry. Mapping on land included structural mapping of ten sites by on-site field mapping and nine sites by remote structural mapping using terrestrial laser scanning technology (TLS). Field work also included periodic monitoring of 14 sites using differential Global Positioning Systems (dGPS) and TLS at 4 sites. Synthetic Aperture Radar was app lied for the entire …

Late Holocene History Of Dune Activity Along The Elkhorn River In Northeastern Nebraska, Rebecca A. Young

School of Natural Resources: Dissertations, Theses, and Student Research

The Nebraska Sand Hills have been an important study area for dune activation and the nature of prehistoric drought events in the Great Plains. However, little has been done to understand the impact of these droughts to smaller dune fields along the eastern margin of the Great Plains. This study focuses on the Stanton dune field which is found about 145 km east of the Sand Hills along the southern edge of the Elkhorn River valley in northeastern Nebraska. With a wetter and slightly cooler climate regime than that of the Nebraska Sand Hills and most other central Great Plains …