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2015

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Articles 1 - 30 of 1152

Full-Text Articles in Earth Sciences

Automatic Detection And Quantification Of Bluff Erosion Events In Single Image Series, Martin D. Hellwig Dec 2015

Automatic Detection And Quantification Of Bluff Erosion Events In Single Image Series, Martin D. Hellwig

Graduate Masters Theses

Many communities along coastlines and riverbanks are threatened by water erosion and hence an accurate model to predict erosion events is needed in order to plan mitigation strategies. Such models need to rely on readily available meteorological data that may or may not be correlated with the occurrence of erosion events. In order to accurately study these potential correlations, researchers need a quantified time series index indicating the occurrence and magnitude of erosion in the studied area. We show that such an index can be obtained by creating and analyzing a single image series using relatively cheap consumer grade digital …


Debris Flow Susceptibility Map For Mount Rainier, Washington Based On Debris Flow Initiation Zone Characteristics From The November, 2006 Climate Event In The Cascade Mountains, Kassandra Lindsey Dec 2015

Debris Flow Susceptibility Map For Mount Rainier, Washington Based On Debris Flow Initiation Zone Characteristics From The November, 2006 Climate Event In The Cascade Mountains, Kassandra Lindsey

Dissertations and Theses

In November 2006 a Pineapple Express rainstorm moved through the Pacific Northwest generating record precipitation, 22 to 50 cm in the two-day event on Mt. Rainier. Copeland (2009) and Legg (2013) identified debris flows in seven drainages in 2006; Inter Fork, Kautz, Ohanapecosh, Pyramid, Tahoma, Van Trump, and West Fork of the White River. This study identified seven more drainages: Carbon, Fryingpan, Muddy Fork Cowlitz, North Puyallup, South Mowich, South Puyallup, and White Rivers. Twenty-nine characteristics, or attributes, associated with the drainages around the mountain were collected. Thirteen were used in a regression analysis in order to develop a susceptibility …


Pre-Mission Input Requirements To Enable Successful Sample Collection By A Remote Field/Eva Team, Barbara A. Cohen, Darlene S. S. Lim, Kelsey E. Young, Anna Brunner, Richard C. Elphic, Audrey Horne, Mary C. Kerrigan, Gordon O. Osinski, John R. Skok, Steven W. Squyres, David Saint-Jacques, Jennifer L. Heldmann Dec 2015

Pre-Mission Input Requirements To Enable Successful Sample Collection By A Remote Field/Eva Team, Barbara A. Cohen, Darlene S. S. Lim, Kelsey E. Young, Anna Brunner, Richard C. Elphic, Audrey Horne, Mary C. Kerrigan, Gordon O. Osinski, John R. Skok, Steven W. Squyres, David Saint-Jacques, Jennifer L. Heldmann

Journal of Human Performance in Extreme Environments

We used a field excursion to the West Clearwater Lake Impact structure as an opportunity to test factors that contribute to the decisions a remote field team (for example, astronauts conducting extravehicular activities (EVA) on planetary surfaces) makes while collecting samples for return to Earth. We found that detailed background on the analytical purpose of the samples, provided to the field team, enables them to identify and collect samples that meet specific analytical objectives. However, such samples are not always identifiable during field reconnaissance activities, and may only be recognized after outcrop characterization and interpretation by crew and/or science team …


U.S. Drought Monitor, December 22, 2015, Richard R. Heim Jr. Dec 2015

U.S. Drought Monitor, December 22, 2015, Richard R. Heim Jr.

United States Agricultural Commodities in Drought Archive

Drought map of the United States for December 22, 2015 (12/22/15) plus: United States crop areas experiencing drought (map), an approximate percentage of crop located in drought by state (bar graph), and the percentage of crop area located in drought during the past 52 weeks (line graph) for corn, soybeans, hay, cattle, and winter wheat.


Apparent Glacially Induced Structural Controls On Limestone Conduit Development In Ohio Caverns, United States, Adrienne M. Watts, Ira D. Sasowsky Dec 2015

Apparent Glacially Induced Structural Controls On Limestone Conduit Development In Ohio Caverns, United States, Adrienne M. Watts, Ira D. Sasowsky

International Journal of Speleology

Rock discontinuities such as bedding planes and joints are important controls on the form that caves take. We examined structural controls on the development of Ohio Caverns. The cave formed in Devonian limestone underlying a small bedrock knob (Mt. Tabor) within the Interior Lowland province, United States. The area has been overridden by continental glaciation multiple times. The bedrock is pervasively fractured, with many curved and wavy near-vertical fractures showing many different orientations. In the case of Ohio Caverns, it appears that the controlling fractures in map view may not be joints sensu stricto, but rather some combination of …


History Of Sigma Gamma Epsilon Honorary Society For Earth Scientists, The Second Twenty-Five Years, 1941-1965, Patricia L. Daniel Dec 2015

History Of Sigma Gamma Epsilon Honorary Society For Earth Scientists, The Second Twenty-Five Years, 1941-1965, Patricia L. Daniel

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.


Foreword To The Special Centennial Publication Of The Compass, James C. Walters Dec 2015

Foreword To The Special Centennial Publication Of The Compass, James C. Walters

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.


Enriched Continental Flood Basalts From Depleted Mantle Melts: Modeling The Lithospheric Contamination Of Karoo Lavas From Antarctica, Jussi S. Heinonen, Arto V. Luttinen, Wendy A. Bohrson Dec 2015

Enriched Continental Flood Basalts From Depleted Mantle Melts: Modeling The Lithospheric Contamination Of Karoo Lavas From Antarctica, Jussi S. Heinonen, Arto V. Luttinen, Wendy A. Bohrson

All Faculty Scholarship for the College of the Sciences

Continental flood basalts (CFBs) represent large-scale melting events in the Earth’s upper mantle and show considerable geochemical heterogeneity that is typically linked to substantial contribution from underlying continental lithosphere. Large-scale partial melting of the cold subcontinental lithospheric mantle and the large amounts of crustal contamination suggested by traditional binary mixing or assimilation-fractional crystallization models are difficult to reconcile with the thermal and compositional characteristics of continental lithosphere, however. The well-exposed CFBs of Vestfjella, western Dronning Maud Land, Antarctica, belong to the Jurassic Karoo large igneous province and provide a prime locality to quantify mass contributions of lithospheric and sublithospheric sources …


Dendrochronology And Middle Miocene Petrified Oak: Modern Counterparts And Interpretation, William E. Wright, Martin J. Streck, Christopher Baisan, W. Walton Wright, Paul Szejner Dec 2015

Dendrochronology And Middle Miocene Petrified Oak: Modern Counterparts And Interpretation, William E. Wright, Martin J. Streck, Christopher Baisan, W. Walton Wright, Paul Szejner

Geology Faculty Publications and Presentations

This study reports the first successful statistical crossdating among many ring width time series from petrified wood, thus providing a replicable continuous annual resolution window into tree growth and environmental influences during the middle Miocene. The petrified samples, of the genus Quercus, originated at the Stinking Water (SW) locality in Oregon, a Miocene-aged exposure associated with the Columbia River Basalts. 40AR/39AR dating on pillow basalt from the locality yielded a weighted Plateau Age of 13.79 ±0.09 Ma placing the death of the trees at the end of the Langhian Stage of the Middle Miocene (15.97±0.05 to 13.65±0.05 …


Sigma Gamma Epsilon In Recent Years, Paula F. Even Dec 2015

Sigma Gamma Epsilon In Recent Years, Paula F. Even

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Patricia L. Daniel covered the first 50 years of Sigma Gamma Epsilon’s existence in The History of Sigma Gamma Epsilon, The First Twenty-Five Years, 1915-1940 and The History of Sigma Gamma Epsilon, The Second Twenty-Five Years, 1941-1965 (Daniel, 1966a, b). Richard L. Ford’s Major Milestones in the Development of Sigma Gamma Epsilon's Core Traditions (Ford, 2012) noted the significant highlights of the Society up until recent times. This article updates the recent noteworthy events of the organization to complete the 100 year history of Sigma Gamma Epsilon. New chapters, recent conventions, the development of two new chapter awards in addition …


43rd Biennial Convention And Centennial Celebration The University Of Kansas: March 27-29, 2015, James C. Walters, Paula F. Even Dec 2015

43rd Biennial Convention And Centennial Celebration The University Of Kansas: March 27-29, 2015, James C. Walters, Paula F. Even

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Sigma Gamma Epsilon, the national honor society in the Earth Sciences, held its 43rd Biennial Convention on the campus of the University of Kansas March 27-29, 2015 in conjunction with its centennial celebration. Alpha Chapter, Sigma Gamma Epsilon’s first chapter, hosted the events. During the convention, Dr. Anthony Walton of the Department of Geology at KU led a half-day field excursion on the Pennsylvanian Stratigraphy of Douglas County, Kansas: Glacioeustatically Modulated Cyclic Deposition on a Remarkably Smooth Shelf. This report provides a summary of the deliberations and actions of the participants at the convention and highlights of the field …


The History Of Sigma Gamma Epsilon The First Twenty-Five Years, 1915-1940, Patricia L. Daniel Dec 2015

The History Of Sigma Gamma Epsilon The First Twenty-Five Years, 1915-1940, Patricia L. Daniel

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Sigma Gamma Epsilon Honor Society for Earth Science students was founded during the spring of 1915 in the home of William H. Twenhofel, Associate Professor of Geology at The University of Kansas. ΣΓΕ was launched nationally in the fall of 1915 with the admittance of Beta Chapter of Pittsburgh University, and today there are more than 100 chapters nation- wide. Originally a "male only" fraternity for geologists, metallurgists, mining, petroleum, and ceramics engineers, for nearly three decades ΣΓΕ has been open to all Earth Science majors and is composed primarily of geology students.

In 80 years, ΣΓΕ has weathered two …


Major Milestones In The Development Of Sigma Gamma Epsilon's Core Traditions, Richard L. Ford Dec 2015

Major Milestones In The Development Of Sigma Gamma Epsilon's Core Traditions, Richard L. Ford

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.


A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman Dec 2015

A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman

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

The Nebraska Sandhills are the largest sand dune system in the Western Hemisphere, and are unique because they remain relatively undisturbed from row crop agriculture. Research in the past two decades demonstrated that the Sandhills are dynamic on millennial timescales, switching between stabilized, vegetated states to non-vegetated, mobilized states. The Sandhills are currently stabilized, but understanding how ecological processes are altered as sand dunes transition from stabilized to mobilized states, provides insight into the thresholds, stability, and resilience of this grassland ecosystem. My research investigated the impacts of vegetation disturbances on ecological processes and the sand dune surface stability. For …


Phosphorus Release Potential Of Agricultural Soils Of The United States, Rebecca A. Young Dec 2015

Phosphorus Release Potential Of Agricultural Soils Of The United States, Rebecca A. Young

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

Phosphorus (P) is one of the leading causes of surface water quality decline in the United States, leading to algal blooms and hypoxia in lakes and streams. Decreasing conservation funds dictate that agencies such as the Natural Resources Conservation Service, maximizes its effectiveness and efficiency in implementing practices to address P management and runoff on agricultural lands. Additional information on P behavior in soil is needed to improve P management plans to reduce pollution risk at the watershed, farm, and field scales. This research focuses on the development of total soil P release models, to be included into assessment and …


Petroleum Play Study Of The Keathley Canyon, Gulf Of Mexico, Jean Pierre Malbrough Dec 2015

Petroleum Play Study Of The Keathley Canyon, Gulf Of Mexico, Jean Pierre Malbrough

LSU New Orleans Theses and Dissertations

Beneath Keathley Canyon (KC) off the Southern Coast of Louisiana and Texas, allochthonous salt bodies have attained thicknesses of over 7620 m (25000 feet), providing excellent seals and migration pathways for hydrocarbons produced by post-rift sedimentary deposition. This study analyzes a small portion of the KC area, utilizing Petrel Seismic software and well information from the KC102 (Tiber) well.

An intra-Miocene wedge, expressed beneath salt, may provide information about movement of allochthonous salt over Wilcox sands, sediment compaction, and hydrocarbon pathways. Progradational sedimentation is the driving force which leads to faulting in the early Miocene, allowing Jurassic salt to rise, …


Response Of Fishes To Restoration Projects In Bayou St. John Located Within The City Of New Orleans, Louisiana, Including Hydrological Characterization And Hydrodynamic Modelling, Patrick W. Smith Dec 2015

Response Of Fishes To Restoration Projects In Bayou St. John Located Within The City Of New Orleans, Louisiana, Including Hydrological Characterization And Hydrodynamic Modelling, Patrick W. Smith

LSU New Orleans Theses and Dissertations

Quantifying the impacts of restoration on coastal waterways is crucial to understanding their effectiveness. Here, I look at the impacts of multiple restoration projects on urban waterways within the city limits of New Orleans, LA, with an emphasis on the response of fishes. First I report the effects of two projects designed to improve exchange down estuary on the hydrologic characteristics of Bayou St. John (BSJ). Within BSJ, flow is dominated by subtidal wind driven processes. Removal of an outdated flood control structure did not appear to alter exchange in BSJ, but removal combined with sector gate openings did. I …


The Role Of The State, Multinational Oil Companies, International Law & The International Community: Intersection Of Human Rights & Environmental Degradation Climate Change In The 21st Century Caused By Traditional Extractive Practices, The Amazon Rainforest, Indigenous People And Universal Jurisdiction To Resolve The Accountability Issue, Marcela Cabrera Luna Dec 2015

The Role Of The State, Multinational Oil Companies, International Law & The International Community: Intersection Of Human Rights & Environmental Degradation Climate Change In The 21st Century Caused By Traditional Extractive Practices, The Amazon Rainforest, Indigenous People And Universal Jurisdiction To Resolve The Accountability Issue, Marcela Cabrera Luna

Master's Theses

Local, national and international conventions that protect indigenous sovereignty and their territories, where many of the resources are extracted from by multinational corporations (MNCs) particularly oil, the number one commodity of the world and cause of climate change, continue to be jeopardized because of the lack of a clear international legal framework that can protect them and potentially hold multinationals accountable for their actions. These practices are causing not only environmental issues to the indigenous and surrounding communities, but climate change is in fact, the real human rights issue of the 21st century and it affects everyone. By using …


Stabilized Least Squares Migration, Graham Ganssle Dec 2015

Stabilized Least Squares Migration, Graham Ganssle

LSU New Orleans Theses and Dissertations

Before raw seismic data records are interpretable by geologists, geophysicists must process these data using a technique called migration. Migration spatially repositions the acoustic energy in a seismic record to its correct location in the subsurface. Traditional migration techniques used a transpose approximation to a true acoustic propagation operator. Conventional least squares migration uses a true inverse operator, but is limited in functionality by the large size of modern seismic datasets. This research uses a new technique, called stabilized least squares migration, to correctly migrate seismic data records using a true inverse operator. Contrary to conventional least squares migration, this …


Submarine Channel Evolution Linked To Rising Salt Dome, Mississippi Canyon, Gulf Of Mexico, Rachel C. Carter Dec 2015

Submarine Channel Evolution Linked To Rising Salt Dome, Mississippi Canyon, Gulf Of Mexico, Rachel C. Carter

LSU New Orleans Theses and Dissertations

By examining halokinetics and channel evolution in a deep-water system, we investigate how submarine channel morphology is affected by changing seascape linked to diapirism. The study area is located in Mississippi Canyon, Gulf of Mexico (GOM), situated directly off the continental slope in a prominent salt dome region. Interactions of salt domes with submarine channels in the GOM are poorly documented. Utilizing 3D seismic data and seismic geomorphology techniques, a long-lived Plio-Pleistocene submarine channel system has been investigated to develop a relationship between variable phases of salt movement and plan-form morphology of preserved channels.

We suggest that halokinetics acts as …


Linear Trend Detection In Serially Dependent Hydrometeorological Data Based On A Variance Correction Spearman Rho Method, Wenpeng Weng, Yuanfang Chen, Stefan Becker, Bo Liu Dec 2015

Linear Trend Detection In Serially Dependent Hydrometeorological Data Based On A Variance Correction Spearman Rho Method, Wenpeng Weng, Yuanfang Chen, Stefan Becker, Bo Liu

Publications and Research

Hydrometeorological data are commonly serially dependent and thereby deviate from the assumption of independence that underlies the Spearman rho trend test. The presence of autocorrelation will influence the significance of observed trends. Specifically, the positive autocorrelation inflates Type І errors, while it deflates the power of trend detection in some cases. To address this issue, we derive a theoretical formula and recommend an appropriate empirical formula to calculate the rho variance of dependent series. The proposed procedure of the variance correction for the Spearman rho method is capable of mitigating the effect of autocorrelation on both, Type І error and …


Coarse Bedload Routing And Dispersion Through Tributary Confluences, Kurt Imhoff, Andrew C. Wilcox Dec 2015

Coarse Bedload Routing And Dispersion Through Tributary Confluences, Kurt Imhoff, Andrew C. Wilcox

Geosciences Faculty Publications

Sediment routing fundamentally influences channel morphology and propagation of disturbances. However, the transport and storage of bedload particles in headwater channel confluences, which may be significant nodes of the channel network in terms of sediment routing, morphology, and habitat, is poorly understood. To characterize routing processes through confluences of headwater channels, we investigate how sediment routing patterns through headwater confluences compare to those described in low-gradient gravel bed river systems, and how confluences affect the dispersive behavior of coarse bedload particles compared to non-confluence reaches. We address these questions with a field tracer experiment using passive-integrated transponder and radio-frequency identification …


Iodp Expedition 347baltic Sea Basin Paleoenvironment And Biosphere, Thomas Andrén, Bo Barker Jørgensen, Carol Cotterill, Sophie Green, Elinor Andrén, Jeanine L. Ash, Thorsten Bauersachs, Barry Cragg, Anne-Sophie Fanget, Annick Fehr, Wojciech Granoszewski, Jer­Oen Groeneveld, Dalton S. Hardisty, Emilio Herrero-Bervera, Outi Hyttinen, Jørn Bo Jensen, Sean Johnson, Michael Kenzler, Aarno Kotilainen, Ulrich Kotthoff, Ian Pg Marshall, E. Martin, S. Obrochta, Sandra Passchier, Nadine B. Quintana Krupinski, Natascha Riedinger, Caroline Slomp, Ian Snowball, Anna Stepanova, Sarah Strano Dec 2015

Iodp Expedition 347baltic Sea Basin Paleoenvironment And Biosphere, Thomas Andrén, Bo Barker Jørgensen, Carol Cotterill, Sophie Green, Elinor Andrén, Jeanine L. Ash, Thorsten Bauersachs, Barry Cragg, Anne-Sophie Fanget, Annick Fehr, Wojciech Granoszewski, Jer­Oen Groeneveld, Dalton S. Hardisty, Emilio Herrero-Bervera, Outi Hyttinen, Jørn Bo Jensen, Sean Johnson, Michael Kenzler, Aarno Kotilainen, Ulrich Kotthoff, Ian Pg Marshall, E. Martin, S. Obrochta, Sandra Passchier, Nadine B. Quintana Krupinski, Natascha Riedinger, Caroline Slomp, Ian Snowball, Anna Stepanova, Sarah Strano

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The Integrated Ocean Drilling Program (IODP) expedition 347 cored sediments from different settings of the Baltic Sea covering the last glacial-interglacial cycle. The main aim was to study the geological development of the Baltic Sea in relation to the extreme climate variability of the region with changing ice cover and major shifts in temperature, salinity, and biological communities. Using the Greatship Manisha as a European Consortium for Ocean Research Drilling (ECORD) mission-specific platform, we recovered 1.6 km of core from nine sites of which four were additionally cored for microbiology. The sites covered the gateway to the North Sea and …


U.S. Drought Monitor, December 15, 2015, Richard Tinker Dec 2015

U.S. Drought Monitor, December 15, 2015, Richard Tinker

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 15, 2015 (12/15/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.


A Preliminary Assessment Of Water Partitioning And Ecohydrological Coupling In Northern Headwaters Using Stable Isotopes And Conceptual Runoff Models, James P. Mcnamara Dec 2015

A Preliminary Assessment Of Water Partitioning And Ecohydrological Coupling In Northern Headwaters Using Stable Isotopes And Conceptual Runoff Models, James P. Mcnamara

Geosciences Faculty Publications and Presentations

We combined a conceptual rainfall-runoff model and input–output relationships of stable isotopes to understand ecohydrological influences on hydrological partitioning in snow-influenced northern catchments. Six sites in Sweden (Krycklan), Canada (Wolf Creek; Baker Creek; Dorset), Scotland (Girnock) and the USA (Dry Creek) span moisture and energy gradients found at high latitudes. A meta-analysis was carried out using the Hydrologiska Byråns Vattenbalansavdelning (HBV) model to estimate the main storage changes characterizing annual water balances. Annual snowpack storage importance was ranked as Wolf Creek > Krycklan > Dorset > Baker Creek > Dry Creek > Girnock. The subsequent rate and longevity of melt were reflected in calibrated parameters …


Mineralogy And Geochemistry Of Late Archean And Paleoproterozoic Granites And Pegmatites In The Northern Penokean Terrane Of Marquette And Dickinson Counties, Michigan, Christopher M. Johnson, Christopher M. Van Daalen Dec 2015

Mineralogy And Geochemistry Of Late Archean And Paleoproterozoic Granites And Pegmatites In The Northern Penokean Terrane Of Marquette And Dickinson Counties, Michigan, Christopher M. Johnson, Christopher M. Van Daalen

LSU New Orleans Theses and Dissertations

This thesis focuses on mineralogy, geochemistry, and origin of eight pegmatites and two spatially associated granites of Late Archean and Paleoproterozoic ages located in Marquette and Dickinson Counties, Michigan. Biotite geochemistry reveals that both granites and all pegmatites are peraluminous and have an orogenic signature. However, bulk composition reveals the Humboldt granite is a peraluminous A-type granite and the Bell Creek granite is a peraluminous mix between I-, S-, and A-type granites. The Republic Mine pegmatite appears to be geochemically similar to the Bell Creek granite and Grizzly pegmatite. The Crockley pegmatite is genetically related to the Humboldt granite. The …


The Force Of Water: Columbia After The Flood, Rebecca Johnson Dec 2015

The Force Of Water: Columbia After The Flood, Rebecca Johnson

Senior Theses

Nearly two months have passed, and South Carolina is still recovering from the unprecedented inundation of rain that pelted down in early October. Record amounts of precipitation pounded the state over just a few days, resulting in the flooding and erosion of land, the deterioration of public infrastructure and the loss of human life and capital.

The worst of it was in the capital city. Columbia recorded the highest water levels and the highest number of fatalities of all the affected areas. The city’s utilities could not handle the torrent of water: dams were destroyed, canals were compromised, roads were …


A Seismic Transect Across West Antarctica: Evidence For Mantle Thermal Anomalies Beneath The Bentley Subglacial Trench And The Marie Byrd Land Dome, Andrew J. Lloyd, Douglas A. Wiens, Andrew A. Nyblade, Sridhar Anandakrishnan, Richard C. Aster, Audrey D. Huerta, Terry J. Wilson, Ian W. D. Dalziel, Patrick J. Shore, Dapeng Zhao Dec 2015

A Seismic Transect Across West Antarctica: Evidence For Mantle Thermal Anomalies Beneath The Bentley Subglacial Trench And The Marie Byrd Land Dome, Andrew J. Lloyd, Douglas A. Wiens, Andrew A. Nyblade, Sridhar Anandakrishnan, Richard C. Aster, Audrey D. Huerta, Terry J. Wilson, Ian W. D. Dalziel, Patrick J. Shore, Dapeng Zhao

All Faculty Scholarship for the College of the Sciences

West Antarctica consists of several tectonically diverse terranes, including the West Antarctic Rift System, a topographic low region of extended continental crust. In contrast, the adjacent Marie Byrd Land and Ellsworth-Whitmore mountains crustal blocks are on average over 1km higher, with the former dominated by polygenetic shield and stratovolcanoes protruding through the West Antarctic ice sheet and the latter having a Precambrian basement. The upper mantle structure of these regions is important for inferring the geologic history and tectonic processes, as well as the influence of the solid earth on ice sheet dynamics. Yet this structure is poorly constrained due …


Quaternary Chronology And Stratigraphy Of Mickey Springs, Oregon, Leslie Allen Mowbray Dec 2015

Quaternary Chronology And Stratigraphy Of Mickey Springs, Oregon, Leslie Allen Mowbray

Dissertations and Theses

Mickey Springs in the Alvord Desert, southeast Oregon, is analogous to other Basin and Range hydrothermal systems where the requisite conditions of heat source and permeable pathways are met through crustal thinning due to normal faulting. This study examines the morphology and lifespan of near-surface spring features through use of ground penetrating radar, thermoluminescence (TL) dating, and elevation modeling. Duration of hydrothermal activity at Mickey Springs has not previously been determined, and age determinations of sinter at the site are conflicting. The reason for and timing of this change in silica saturation in the hydrothermal fluid has not been resolved. …


Investigating The Complexity Of Impact Crater Ejecta, Michael Raymond Zanetti Dec 2015

Investigating The Complexity Of Impact Crater Ejecta, Michael Raymond Zanetti

Arts & Sciences Graduate Student Theses and Dissertations

The formation of an impact crater ejecta blanket can be viewed as a form of organized chaos. Material that is ejected from a crater is heavily brecciated, but falls back to the surface along ballistic trajectories, generally preserving an inverted sense of the original stratigraphy. As the ejecta re-impacts the area surrounding the crater it forms a thick blanket of ejected material and reworked target surface that gradually thins away from the crater rim. Within the crater, crater modification processes, such as wall terrace formation and impact melt drainage, transform the crater in expectable ways. The approach adopted in this …