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Articles 361 - 390 of 1124
Full-Text Articles in Earth Sciences
High-Resolution Elevation Mapping Of The Mcmurdo Dry Valleys, Antarctica, And Surrounding Regions, Andrew G. Fountain, Juan C. Fernandez-Diaz, Maciej K. Obryk, Joseph Levy, Michael N. Gooseff, David J. Van Horn, Paul Morin, Ramesh Shrestha
High-Resolution Elevation Mapping Of The Mcmurdo Dry Valleys, Antarctica, And Surrounding Regions, Andrew G. Fountain, Juan C. Fernandez-Diaz, Maciej K. Obryk, Joseph Levy, Michael N. Gooseff, David J. Van Horn, Paul Morin, Ramesh Shrestha
Geology Faculty Publications and Presentations
We present detailed surface elevation measurements for the McMurdo Dry Valleys, Antarctica derived from aerial lidar surveys flown in the austral summer of 2014–2015 as part of an effort to understand geomorphic changes over the past decade. Lidar return density varied from 2 to > 10 returns m−2with an average of about 5 returns m−2. Vertical and horizontal accuracies are estimated to be 7 and 3 cm, respectively. In addition to our intended targets, other ad hoc regions were also surveyed including the Pegasus flight facility and two regions on Ross Island, McMurdo Station, Scott Base (and surroundings), and the coastal …
Observed Changes In Climate And Streamflow In The Upper Rio Grande Basin, Shaleene Chavarria
Observed Changes In Climate And Streamflow In The Upper Rio Grande Basin, Shaleene Chavarria
Earth and Planetary Sciences ETDs
Observed streamflow and climate data are used to test the hypothesis that climate change is already affecting the streamflow volume derived from snow accumulation in ways consistent with climate model-based projections of 21st century streamflow. Annual and monthly changes in streamflow volume and surface climate variables on the upper Rio Grande (URG) near its headwaters in southern Colorado are assessed for water years 1958-2015. Trends in discharge are examined together with variations in snow water equivalent and surface climate variables. Results indicate that temperatures in the basin have increased significantly primarily in the winter and spring seasons, April 1 snow …
Quantitative Literacy In The Affective Domain: Computational Geology Students’ Reactions To Devlin’S The Math Instinct, Victor J. Ricchezza, H. L. Vacher
Quantitative Literacy In The Affective Domain: Computational Geology Students’ Reactions To Devlin’S The Math Instinct, Victor J. Ricchezza, H. L. Vacher
Numeracy
Building on suggestions from alumni from a recent interview project, students in Computational Geology at the University of South Florida were tasked with reading a popular non-fiction book on mathematics and writing about the book and their feelings about math. The book, The Math Instinct by Keith Devlin, was chosen because we believed it would give the students something interesting to write about and not because we had any expectations in particular about what it might reveal about or do for their math anxiety. The nature of the responses received from the students led to the performance of a post-hoc …
The Influence Of Long-Term Anthropogenically-Induced Compaction On Select Properties Of Soils In The Midwestern United States, Eric C. Brevik
The Influence Of Long-Term Anthropogenically-Induced Compaction On Select Properties Of Soils In The Midwestern United States, Eric C. Brevik
Georgia Journal of Science
Soil compaction by heavy equipment has become one of the most important problems in modern large-scale plant production, but one area that has not received much attention is the effect of soil compaction on prairie soils over time periods in excess of about 10 years. This study addresses this issue by comparing properties in compacted to noncompacted soils in an abandoned farmyard and along a preserved stretch of the Mormon Trail. Properties compared include soil morphology, bulk density, carbon, C/N ratio, and apparent electrical conductivity (ECa). Bulk density, organic carbon, and ECa values were consistently different in …
Developing Sustainable Models Of Arsenic-Mitigation Technologies In The Middle-Ganga Plain In India, Sushant K. Singh, Robert Taylor, Haiyan Su
Developing Sustainable Models Of Arsenic-Mitigation Technologies In The Middle-Ganga Plain In India, Sushant K. Singh, Robert Taylor, Haiyan Su
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
This study seeks to understand factors that guide the decision-making process to adopt and implement the available arsenic-mitigation technologies in rural areas in the middle-Ganga Plain in India. A total of 340 households comprising 2500 people were surveyed. Socio-economic and demographic factors, water and sanitation status, time spent and distance travelled to collect water, arsenic awareness, willingness to pay (WTP) for arsenic-free water, people's trust in others and in institutions, social capital in communities, and preferences for sustainable arsenic-mitigation options were investigated. Arsenic treatment units (filters) and piped water supply systems were the most preferred sustainable arsenic-mitigation options in the …
The Potential Effects Of Percolating Snowmelt On Palynological Records From Firn And Glacier Ice, Michael E. Ewin, Carl A. Reese, Matthew A. Nolan
The Potential Effects Of Percolating Snowmelt On Palynological Records From Firn And Glacier Ice, Michael E. Ewin, Carl A. Reese, Matthew A. Nolan
Faculty Publications
The effects of meltwater percolation on pollen in snow, firn and glacial ice are not fully understood and currently hamper the use of pollen in ice-core studies of paleoclimate. Several studies have suggested that, due to grain size, pollen is not mobilized by meltwater transport. However, these findings contradict many ice-core pollen studies that show pollen concentrations in snow and firn are much higher than concentrations found in the ice layers they eventually form. This study addresses one aspect of this question by investigating whether meltwater percolation can effectively transport pollen within a snowpack. We used nine Styrofoam coolers filled …
Stratigraphic Architecture And Lithofacies Of High-Frequency Deltaic Sequences: Virtual Outcrop Analysis Of The Upper Cretaceous (Turonian) Ferron Sandstone Member Of The Mancos Shale, South-Central Utah, Usa, Conor J. Horton
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Sequence stratigraphic models for low-accommodation settings are not well-formulated and lack documented examples illustrating lithofacies stratal stacking pattern complexities. Presented herein is a detailed stratigraphic analysis of the Upper Cretaceous (Turonian) Ferron Sandstone Member of the Mancos Shale Formation; a fluvial-deltaic succession that primarily accumulated under forced-regressive, falling stage systems tracts during decreasing accommodation. The small (4 km2) study area is located at the connecting point of a 67 km long, depositional strike-oriented and a 30 km long, depositional-dip transect within the western-limb of the Henry Mountains Syncline. Detailed outcrop sections and digital Light Detection and Ranging (LiDAR) derived Virtual …
Morphodynamics And Sediment Pathways Of The John's Pass-Blind Pass Dual-Inlet System: Pinellas County, Florida, Mark H. Horwitz
Morphodynamics And Sediment Pathways Of The John's Pass-Blind Pass Dual-Inlet System: Pinellas County, Florida, Mark H. Horwitz
USF Tampa Graduate Theses and Dissertations
The morphodynamics of an inlet channel draining an estuary or bay are governed by a complex system of temporally and spatially varying physical processes, including wind, waves, tides, sediment transport, and both tide and wave driven currents. In addition, sediment availability and characteristics in conjunction with underlying geologic framework bear on the morphology and morphologic behavior of an inlet system. This study examines the morphodynamics, sediment transport patterns and time-series morphologic change of John’s Pass and Blind Pass, two structured tidal inlets that collectively make up a dual-inlet system sharing the tidal prism of northern Boca Ciega Bay, in Pinellas …
Block Motion Changes In Japan Triggered By The 2011 Great Tohoku Earthquake, Brendan Meade, John P. Loveless
Block Motion Changes In Japan Triggered By The 2011 Great Tohoku Earthquake, Brendan Meade, John P. Loveless
Geosciences: Faculty Publications
Plate motions are governed by equilibrium between basal and edge forces. Great earthquakes may induce differential static stress changes across tectonic plates, enabling a new equilibrium state. Here we consider the torque balance for idealized circular plates and find a simple scalar relationship for changes in relative plate speed as a function of its size, upper mantle viscosity, and coseismic stress changes. Applied to Japan, the 2011 MW59:0 Tohoku earthquake generated coseismic stresses of 102 –105 Pa that could have induced changes in motion of small (radius 100 km) crustal blocks within Honshu. Analysis of timedependent GPS velocities, with corrections …
Nuclear Weapons In A Changing Climate: Probability, Increasing Risks, And Perception, Adam Liska, Tyler R. White, Eric Holley, Robert J. Oglesby
Nuclear Weapons In A Changing Climate: Probability, Increasing Risks, And Perception, Adam Liska, Tyler R. White, Eric Holley, Robert J. Oglesby
Adam Liska Papers
Many people tend to think that the outcome of any nuclear weapons use today will result in an escalatory situation with apocalyptic outcomes for the countries involved. Yet many factors are increasing the probability of the limited use of nuclear weapons (e.g., 1 to 20 warheads) in a range of conflict scenarios. Previous atmospheric model simulations of regional nuclear conflicts employing many relatively small bombs have been estimated to cause a global “nuclear autumn,” with great reductions in agricultural productivity, stratospheric ozone loss, and spread of hazardous radioactive fallout. The totality of these effects would result in widespread damage …
Great Plains Geology: My Personal Journey, Robert F. Diffendal Jr.
Great Plains Geology: My Personal Journey, Robert F. Diffendal Jr.
Robert F. Diffendal, Jr., Publications
In 2014 my good friend and former boss, Richard (Rick) Edwards, Director of the University of Nebraska's Center for Great Plains Studies asked me to consider writing a small book about the geology of the Great Plains as part of a series of books exploring many aspects of this marvelous place. I thought his request over and told Rick that I would give it a try. The series is being published by the University of Nebraska Press, the first completed book of which is Great Plains Indians written by my colleague David Wishart.
I wrote up an outline of my …
The Prairie Post Quarterly Newsletter Of The High Plains Regional Climate Center- July 2017, Natalie Umphlett, Bill Sorensen, Crystal J. Stiles
The Prairie Post Quarterly Newsletter Of The High Plains Regional Climate Center- July 2017, Natalie Umphlett, Bill Sorensen, Crystal J. Stiles
Prairie Post: Quarterly Newsletter of the High Plains Regional Climate Center
Inside this issue:
Message from the interim director........................................1
Staff spotlight...........................1
Drought update.......................2
Update on regional climate conditions..................................2
Product highlights..................3
AWDN information.................4
Climate adaptation award announcement.........................4
Workshops update..................5
Recent and upcoming travel and activities.............................6
Volcanic Initiation Of The Eocene Heart Mountain Slide, Wyoming, Usa, Mark D. Schmitz
Volcanic Initiation Of The Eocene Heart Mountain Slide, Wyoming, Usa, Mark D. Schmitz
Geosciences Faculty Publications and Presentations
The Eocene Heart Mountain slide of northwest Wyoming covers an area of as much as 5000 km2 and includes allochthonous Paleozoic carbonate and Eocene volcanic rocks with a run-out distance of as much as 85 km. Recent geochronologic data indicated that the emplacement of the slide event occurred at ∼48.9 Ma, using laser ablation inductively coupled plasmamass spectrometry (LA-ICPMS) extracted fromU-Pb zircon ages frombasal layer and injectite carbonate ultracataclasite (CUC). We now refine that age with U-Pb results from a lamprophyre diatreme that is temporally and spatially related to the CUC injectites. The ages for the lamprophyre zircons are …
Epikarst Hydrogeochemical Changes In Telogenetic Karst Systems In South-Central Kentucky, Leah Jackson
Epikarst Hydrogeochemical Changes In Telogenetic Karst Systems In South-Central Kentucky, Leah Jackson
Masters Theses & Specialist Projects
Telogenetic epikarst carbon sourcing and transport processes and the associated hydrogeochemical responses are often complex and dynamic. Among the processes involved in epikarst development is a highly variable storage and flow relationship that is often influenced by the type, rate, and amount of dissolution kinetics involved. Diffusion rates of CO2 in the epikarst zone may drive hydrogeochemical changes that influence carbonate dissolution processes and conduit formation. Most epikarst examinations of these defining factors ignore regional-scale investigations in favor of characterizing more localized processes. This study aims to address that discrepancy through a comparative analysis of two telogenetic epikarst systems under …
Shower Atomization, Chirag Ayappa Ravishankar,
Shower Atomization, Chirag Ayappa Ravishankar,
Masters Theses & Specialist Projects
The research will help to design a shower for Dr. Chelson’s shelter, which can control the water flow, pressure and duration of the shower, which optimizes the utilization of water. The showers could be used in drought-hit areas where water is very scarce, as daily sanitation needs are necessary to keep a person safe and healthy without wasting water. The report from, World Health Organization shows that showers consume the most water. A timed shower could help resolve this issue through eliminating the wastage. Eco-friendly environmentalists may also be attracted to the showers, as their main purposes are to save …
Measuring Inorganic Carbon Fluxes From Carbonate Mineral Weathering From Large River Basins: The Ohio River Basin, Autumn B. Singer
Measuring Inorganic Carbon Fluxes From Carbonate Mineral Weathering From Large River Basins: The Ohio River Basin, Autumn B. Singer
Masters Theses & Specialist Projects
Rising atmospheric CO2 concentrations have motivated efforts to better quantify reservoirs and fluxes of Earth’s carbon. Of these fluxes from the atmosphere, one that has received relatively little attention is the atmospheric carbon sink associated with carbonate mineral dissolution. Osterhoudt (2014) and Salley (2016) explored new normalization techniques to improve and standardize a process for measuring this flux over large river basins. The present research extends this work to the 490,600 km2 Ohio River drainage basin and 11 subbasins. The study estimated the DIC flux leaving these basins between October 1, 2013, and September 30, 2014, based on secondary hydrogeochemical, …
Mesonets: Mesoscale Weather And Climate Observations For The United States, Rezaul Mahmood, Ryan Boyles, Kevin Brinson, Christopher Fiebrich, Stuart Foster, Ken Hubbard, David Robinson, Jeff Andresen, Dan Leathers
Mesonets: Mesoscale Weather And Climate Observations For The United States, Rezaul Mahmood, Ryan Boyles, Kevin Brinson, Christopher Fiebrich, Stuart Foster, Ken Hubbard, David Robinson, Jeff Andresen, Dan Leathers
High Plains Regional Climate Center: Staff Publications
Mesoscale in situ meteorological observations are essential for better understanding and forecasting the weather and climate and to aid in decision-making by a myriad of stakeholder communities. They include, for example, state environmental and emergency management agencies, the commercial sector, media, agriculture, and the general public. Over the last three decades, a number of mesoscale weather and climate observation networks have become operational. These networks are known as mesonets. Most are operated by universities and receive different levels of funding. It is important to communicate the current status and critical roles the mesonets play. Most mesonets collect standard meteorological data …
Nonmeteorological Influences On Severe Thunderstorm Warning Issuance: A Geographically Weighted Regression-Based Analysis Of County Warning Area Boundaries, Land Cover, And Demographic Variables, Megan L. White, J. Anthony Stallins
Nonmeteorological Influences On Severe Thunderstorm Warning Issuance: A Geographically Weighted Regression-Based Analysis Of County Warning Area Boundaries, Land Cover, And Demographic Variables, Megan L. White, J. Anthony Stallins
Geography Faculty Publications
Studies have shown that the spatial distribution of severe thunderstorm warnings demonstrates variation beyond what can be attributed to weather and climate alone. Investigating spatial patterns of these variations can provide insight into nonmeteorological factors that might lead forecasters to issue warnings. Geographically weighted regression was performed on a set of demographic and land cover descriptors to ascertain their relationships with National Weather Service (NWS) severe thunderstorm warning polygons issued by 36 NWS forecast offices in the central and southeastern United States from 2008 to 2015. County warning area (CWA) boundaries and cities were predominant sources of variability in warning …
Biogeochemical Interactions In Flooded Underground Mines, Renee Schmidt
Biogeochemical Interactions In Flooded Underground Mines, Renee Schmidt
Graduate Theses & Non-Theses
This study presents a biogeochemical analysis of microbial communities in flooded underground mines in Butte, Montana, USA. Samples were collected from nine mineshafts representing three distinct geochemical zones. These zones consist of the East, West, and Outer Camp mines. The East Camp mines, bordering the Berkeley Pit Superfund site, have the highest concentrations of dissolved metals and the most acidic pH values. Dissolved metal concentrations in the West Camp are one to three orders of magnitude lower than in the East Camp and have nearly neutral pH values. The Outer Camp mines have similar metal concentrations to the West Camp …
Aeromagnetic And Spectral Expressions Of Rare Earth Element Deposits In Gallinas Mountains Area, Central New Mexico, Usa, Mo Li
Graduate Theses & Non-Theses
The Gallinas Mountains located in the conjunction of Lincoln County and Torrance County, New Mexico, USA are a series of alkaline volcanic rocks intruded into Permian sedimentary rocks. The Gallinas Mountains area is known to host fluorite and copper as veins containing bastnasite while hydrothermally altered rocks associated with iron oxides have been found in the area as well. In this study, multispectral band ratio method was used for surface mineral interpretation by processing satellite image, while aeromagnetic inversion method was applied using aeromagnetic data, digital elevation model and physical properties for 2-D subsurface structure modeling. Bastnasite has higher magnetic …
Tracking Potential Leakage Of Tailings-Lake Water Into Background Groundwater In Butte, Montana, Using Geochemical And Stable Isotope Tracers, Matthew Berzel
Tracking Potential Leakage Of Tailings-Lake Water Into Background Groundwater In Butte, Montana, Using Geochemical And Stable Isotope Tracers, Matthew Berzel
Graduate Theses & Non-Theses
This study was conducted to identify environmental tracers using water chemistry and stable isotopes in the Moulton Road area adjacent to the Yankee Doodle tailings impoundment north of Butte, Montana. The water level of the tailings lake is being raised as tailings slurry is pumped up to the impoundment, and numerous residential wells are located in close proximity. Although it has an alkaline pH (> 9), the water in the tailings lake is much higher in some chemical constituents than the wells and some of these constituents could be used as tracers to determine if lake water is migrating out …
Comparing Distributed Acoustic Sensing To Three-Component Geophones In An Underground Mine, Nikolas Nesladek
Comparing Distributed Acoustic Sensing To Three-Component Geophones In An Underground Mine, Nikolas Nesladek
Graduate Theses & Non-Theses
Geophones have become the industry standard for seismic data collection. However, a relatively new method is gaining popularity called Distributed Acoustic Sensing (DAS). DAS uses changes in backscattered light of a fiber-optic cable to detect strain from acoustic energy. The purpose of this project was to make a direct comparison between DAS and three component geophones, specifically in a mining setting. Experiments were done in the Underground Education Mining Center on the campus of Montana Tech. The sources used for this project were vertical sledgehammer shots, oriented shear sledgehammer shots, and blasting caps set off in both unstemmed and stemmed …
Evidence For Late Pliocene Deglacial Megafloods From Giant Sediment Waves In The Northern Gulf Of Mexico, Zexuan Wang
Evidence For Late Pliocene Deglacial Megafloods From Giant Sediment Waves In The Northern Gulf Of Mexico, Zexuan Wang
Masters Theses & Specialist Projects
Laurentide Ice Sheet outburst floods to the Gulf of Mexico have been mainly documented based on deep-sea cores, especially the megafloods, only during the last several interglacial episodes in the late Pleistocene. The paleoclimatic significance of giant sedimentary structures developed under unconfined Froude-supercritical turbidity currents in subaqueous settings is considerably under-examined. This research extensively documents >20-km-wide and 200-m-thick Plio-Pleistocene giant sediment waves for the first time on the northern Gulf of Mexico continental slope using 3D seismic data, which show waveform morphology in unprecedented detail. The results suggest that such large-scale bedforms were formed under sheet-like unconfined Froudesupercritical turbidity currents …
Droughtscape, Summer 2017, National Drought Mitigation Center
Droughtscape, Summer 2017, National Drought Mitigation Center
DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)
Contents
Drought policy write shops conclude in Caribbean
Drought encroaches on Northern Plains in second quarter
Impact tool racks up submissions in second quarter
Maps on new website highlight drought effects on ag industry
Centers release new flash drought tool: QuickDRI
NDMC contributes to EU report on disaster risk management
Groups earn Climate Adaptation award for work with tribes
NDMC, ICPAC director talk collaboration on drought in Greater Horn of Africa
Up next in MENA: Drought vulnerability assessments
Modeling The Isotopic Evolution Of Snowpack And Snowmelt: Testing A Spatially Distributed Parsimonious Approach, Pertti Ala-Aho, Doerthe Tetzlaff, James P. Mcnamara, Hjalmar Laudon
Modeling The Isotopic Evolution Of Snowpack And Snowmelt: Testing A Spatially Distributed Parsimonious Approach, Pertti Ala-Aho, Doerthe Tetzlaff, James P. Mcnamara, Hjalmar Laudon
Geosciences Faculty Publications and Presentations
Use of stable water isotopes has become increasingly popular in quantifying water flow paths and travel times in hydrological systems using tracer-aided modeling. In snow-influenced catchments, snowmelt produces a traceable isotopic signal, which differs from original snowfall isotopic composition because of isotopic fractionation in the snowpack. These fractionation processes in snow are relatively well understood, but representing their spatiotemporal variability in tracer-aided studies remains a challenge. We present a novel, parsimonious modeling method to account for the snowpack isotope fractionation and estimate isotope ratios in snowmelt water in a fully spatially distributed manner. Our model introduces two calibration parameters that …
Origins Of Late- Pleistocene Coastal Dune Sheets, Magdalena And Guerrero Negro, From Continental Shelf Low-Stand Supply (70-20 Ka), Under Conditions Of Southeast Littoral- And Eolian-Sand Transport, In Baja California Sur, Mexico, Curt D. Peterson, Janette Murillo-Jiminez, Errol Stock, David M. Price, Steve W. Hostetler, David Percy
Origins Of Late- Pleistocene Coastal Dune Sheets, Magdalena And Guerrero Negro, From Continental Shelf Low-Stand Supply (70-20 Ka), Under Conditions Of Southeast Littoral- And Eolian-Sand Transport, In Baja California Sur, Mexico, Curt D. Peterson, Janette Murillo-Jiminez, Errol Stock, David M. Price, Steve W. Hostetler, David Percy
Geology Faculty Publications and Presentations
Shallow morpho-stratigraphic sections (n = 11) in each of two large coastal dune sheets including the Magdalena (7000 km2) and Guerrero Negro (8000 km2) dune sheets, from the Pacific Ocean side of Baja California Sur, Mexico, have been analyzed for dune deposit age. The shallow morpho-stratigraphic sections (∼2-10 m depth) include 11 new TL and 14C ages, and paleosol chronosequences, that differentiate cemented late Pleistocene dune deposits (20.7 ± 2.1 to 99.8 ± 9.4 ka) from uncemented Holocene dune deposits (0.7 ± 0.05 to at least 3.2 ± 0.3 ka). Large linear dune ridges (5-10 m …
Morphometric Changes In Semicircular Canal Shape Within Theropoda (Dinosauria: Saurischia) And Their Dietary Implications, James Logan King
Morphometric Changes In Semicircular Canal Shape Within Theropoda (Dinosauria: Saurischia) And Their Dietary Implications, James Logan King
Master's Theses or Doctor of Nursing Practice
Theropods were a suborder of dinosaurs that displayed a large variety of dietary preferences throughout the Mesozoic and into the Cenozoic as modern birds. Being ancestrally carnivorous, many of the large-bodied early theropods were hypercarnivorous; however, members of Theropoda diversified their diets into omnivory and herbivory. Modern vertebrates with different dietary preferences have different spatial sensitivities to changes in head and body movement. In order to test if theropod diet plays a major role in the rostral (RSC), caudal (CSC), and lateral (LSC) semicircular canal shape, therizinosaurs, tyrannosaurids, ratites, an allosaurid, an ornithomimid, and a phorusrhacid were analyzed via 2D …
Trophic Dynamics Of Flathead Catfish In The Missouri River Bordering Nebraska, Dylan R. Turner
Trophic Dynamics Of Flathead Catfish In The Missouri River Bordering Nebraska, Dylan R. Turner
School of Natural Resources: Dissertations, Theses, and Student Research
Understanding the trophic dynamics of large, riverine ecosystems is complex and requires knowledge from several inputs and outputs of the ecosystem. Most riverine ecosystems have been altered in some way whether through damming, channelizing, or diverting water. The Missouri River is not immune to these anthropogenic alterations. The river has dams throughout its middle portion and is channelized from Sioux City, Iowa to its confluence with the Mississippi River. Flathead Catfish pylodictus olivarius are one of the most ecologically harmful introduced species but little research has looked at the influence native populations of Flathead Catfish have on native prey populations …
Middle Miocene Paleoenvironmental Reconstruction Of The Central Great Plains From Stable Carbon Isotopes In Large Mammals, Willow H. Nguy
Middle Miocene Paleoenvironmental Reconstruction Of The Central Great Plains From Stable Carbon Isotopes In Large Mammals, Willow H. Nguy
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Middle Miocene (18-12 Mya) mammalian faunas of the North American Great Plains contained a much higher diversity of apparent browsers than any modern biome. This has been attributed to greater primary productivity, which may have supported greater browser diversity that commonly corresponds with densely vegetated habitats. However, several lines of proxy evidence suggest that open woodlands or savannas dominated middle Miocene biomes; neither of which support many browsers today. Stable carbon isotopes in mammalian herbivore tooth enamel were used to reconstruct vegetation structure of middle Miocene biomes.
Stable carbon isotopes in C3 dominated environments reflect vegetation density and herbivores …
A Case Study In Basement And Surface Structure Relationships And Their Implications For Fault Reactivation, Sawtooth Range, Mt, Jason M. Palu
A Case Study In Basement And Surface Structure Relationships And Their Implications For Fault Reactivation, Sawtooth Range, Mt, Jason M. Palu
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The reactivation of pre-existing basement structures affects the geometry of subsequent deformation structures. A case study analyzing the results of these interactions can be used to examine multiple fold-thrust systems and lead to valuable deformation predictions. These predictions include the potential for hydrocarbon traps or seismic risk in an actively deforming area. This case study examined the development of structures close to the Augusta Syncline in the Sawtooth Range, Montana (USA), using: 1) an ArcGIS map of basement structures, based on analysis of gravimetric and aeromagnetic data, seismic data, and well logs; 2) an ArcGIS map of the surface deformation …