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Articles 301 - 330 of 437
Full-Text Articles in Geology
User Guide For Luminescence Sampling In Archaeological And Geological Context, Michelle C. Summa-Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon A. Mahan
User Guide For Luminescence Sampling In Archaeological And Geological Context, Michelle C. Summa-Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon A. Mahan
Geosciences Faculty Publications
Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material …
Toxicity Of Fluorescent Tracers And Their Degradation Byproducts, Philippe Gombert, Hugues Biaudet, René De Sèze, Pascal Pandard, Jean Carré
Toxicity Of Fluorescent Tracers And Their Degradation Byproducts, Philippe Gombert, Hugues Biaudet, René De Sèze, Pascal Pandard, Jean Carré
International Journal of Speleology
Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and …
Discovery And Geology Of The Guinness World Record Lake Copper, Lake Superior, Michigan, Theodore J. Bornhorst, Robert Barron
Discovery And Geology Of The Guinness World Record Lake Copper, Lake Superior, Michigan, Theodore J. Bornhorst, Robert Barron
A. E. Seaman Mineral Museum Publications
No abstract provided.
Effects Of Habitat Restoration On Soil Retention On Santa Rosa Island, Michael Perez, Kathryn Mceachern, Ken Niessen
Effects Of Habitat Restoration On Soil Retention On Santa Rosa Island, Michael Perez, Kathryn Mceachern, Ken Niessen
STAR Program Research Presentations
Ranching began on Santa Rosa Island in the 1840’s, consequently introducing nonnative megafauna that put novel selective grazing pressures on endemic plant species. Their movement patterns also altered substrate integrity as the land became denuded of any stabilizing vegetation. Dense groves of island oak (Q. tomentella) are known to aid in sediment deposition and retention. The groves also function to collect water during periods of intense fog common to the island. This experiment sought to determine whether sediment is being lost or deposited on a ridge in the middle of the island containing a grove of Q. tomentella …
Nebraska, Usa: Wonderful Fossils, Natural History Museums And Public Art Depicting Fossils, Robert F. Diffendal Jr.
Nebraska, Usa: Wonderful Fossils, Natural History Museums And Public Art Depicting Fossils, Robert F. Diffendal Jr.
Robert F. Diffendal, Jr., Publications
Nebraska is known by vertebrate palaeontologists as the place in North America where there is a very complete Cenozoic geologic record of mammalian evolution over the last thirty-five million years or so. All you have to do is visit any of the many major natural history museums in the USA and in many countries around the world, including the UK, to see fossil skulls, articulated skeletons and large slabs of rock containing bones of fossil mammals from Nebraska to verify this assertion. Nebraska is also the site of Cretaceous rocks containing the oldest known Cretaceous fossil flower and many other …
Greater Sage-Grouse Population Trends Across Wyoming, David R. Edmunds, Cameron L. Aldridge, Michael S. O'Donnell, Adrian P. Monroe
Greater Sage-Grouse Population Trends Across Wyoming, David R. Edmunds, Cameron L. Aldridge, Michael S. O'Donnell, Adrian P. Monroe
United States Geological Survey: Staff Publications
The scale at which analyses are performed can have an effect on model results and often one scale does not accurately describe the ecological phenomena of interest (e.g., population trends) for wide-ranging species: yet, most ecological studies are performed at a single, arbitrary scale. To best determine local and regional trends for greater sage-grouse (Centrocercus urophasianus) in Wyoming, USA, we modeled density-independent and -dependent population growth across multiple spatial scales relevant to management and conservation (Core Areas [habitat encompassing approximately 83% of the sage-grouse population on ~24% of surface area in Wyoming], local Working Groups [7 regional areas for …
Elemental Contamination Of An Ancient Copper Mine In Killarney National Park, Killarney, Ireland, Courtney Chouinard
Elemental Contamination Of An Ancient Copper Mine In Killarney National Park, Killarney, Ireland, Courtney Chouinard
Geology: Student Scholarship & Creative Works
Ross Island Copper Mine, located in Killarney National Park, Killarney, Ireland, is known for archeological artifacts of copper from the Bronze Age. Copper production surged in the late 1700s and into the mid-1800s. The mine included both open pits (e.g. Blue Hole) and underground excavations (e.g. Western Mine). Copper veins were found in the Mississippian-aged limestone bedrock along with chalcopyrite and tennantite ore. In 1912, tourism had become the main source of income in the area, and the mines and the land surrounding them were remediated and became a part of the national park. Mine shafts were filled in, waste …
Natural Recession Of The Eastern Margin Of The Leofnard Salt In Western Canada, Neil Lennart Anderson, Robert James Sidford Brown, Dale A. Cederwall
Natural Recession Of The Eastern Margin Of The Leofnard Salt In Western Canada, Neil Lennart Anderson, Robert James Sidford Brown, Dale A. Cederwall
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The Lloydminster area (T35-65, R15W3M-10W4M) of east-central Alberta and west-central Saskatchewan, Canada, is dissected by the north-northwest trending updip active dissolution margin, of the Devonian Leofnard Member rock salt. West of this margin, up to 150 m of rock salt is preserved; updip and to the east, the salt has mostly been leached from the rock record. The margin is up to 40 km wide and characterized by extreme local variations in net salt thickness. The dissolution of the Leofnard rock salt in the Lloydminster area has resulted in the entrapment of significant hydrocarbon accumulation. Stratigraphic traps, for example, have …
Evaporite Karst Geohazards In The Delaware Basin, Texas: Review Of Traditional Karst Studies Coupled With Geophysical And Remote Sensing Characterization, Kevin W. Stafford, Wesley A. Brown, Jon T. Ehrhart, Adam F. Majzoub, Jonathan D. Woodard
Evaporite Karst Geohazards In The Delaware Basin, Texas: Review Of Traditional Karst Studies Coupled With Geophysical And Remote Sensing Characterization, Kevin W. Stafford, Wesley A. Brown, Jon T. Ehrhart, Adam F. Majzoub, Jonathan D. Woodard
Faculty Publications
Evaporite karst throughout the Gypsum Plain of west Texas is complex and extensive, including manifestations ranging from intrastratal brecciation and hypogene caves to epigene features and suffosion caves. Recent advances in hydrocarbon exploration and extraction has resulted in increased infrastructure development and utilization in the area; as a result, delineation and characterization of potential karst geohazards throughout the region have become a greater concern. While traditional karst surveys are essential for delineating the subsurface extent and morphology of individual caves for speleogenetic interpretation, these methods tend to underestimate the total extent of karst development and require surficial manifestation of karst …
Origin Of Graphite In The Southwestern Grenville Province, Mehmet F. Taner, Cameron Drever, Chris Yakymhuk, Fred Longstaffe
Origin Of Graphite In The Southwestern Grenville Province, Mehmet F. Taner, Cameron Drever, Chris Yakymhuk, Fred Longstaffe
Earth Sciences Publications
Two graphite deposits in the southwestern Grenville Province are investigated to evaluate the origin of graphitic carbon and to test if the graphite mineralization is syngenetic or epigenetic. Graphite mineralization in the Bissett Creek deposit is characterized by homogeneously distributed and disseminated graphite flakes (approximately 1 to 5 mm in size and 2 to 10 vol.%) within graphitic gneisses. The graphite flakes are intergrown with metamorphic minerals, most notably biotite. The Montpellier graphite showing in Qu´ebec contains graphite concentrations of up to 20 vol.%. In contrast to the disseminated and homogenously distributed graphite in the Bissett Creek deposit, graphite mineralization …
Taphonomic Problems In Reconstructing Sea-Level History From The Late Quaternary Marine Terraces Of Barbados, Daniel R. Muhs, Kathleen R. Simmons
Taphonomic Problems In Reconstructing Sea-Level History From The Late Quaternary Marine Terraces Of Barbados, Daniel R. Muhs, Kathleen R. Simmons
United States Geological Survey: Staff Publications
Although uranium series (U-series) ages of growth-position fossil corals are important to Quaternary sea-level history, coral clast reworking from storms can yield ages on a terrace dating to more than one high-sea stand, confounding interpretations of sea-level history. On northern Barbados, U-series ages corals from a thick storm deposit are not always younger with successively higher stratigraphic positions, but all date to the last interglacial period (~127 ka to ~112 ka), Marine Isotope Substage (MIS) 5.5. The storm deposit ages are consistent with the ages of growth-position corals found at the base of the section and at landward localities on …
Balancing Stability And Flexibility In Adaptive Governance: An Analysis Of Tools Available In U.S. Environmental Law, Robin Kundis Craig, Ahjond S. Garmestani, Craig R. Allen, Craig Anthony (Tony) Arnold, Hannah E. Birge, Hannah Birge, Daniel A. Decaro, Alexander K. Fremier, Alexander K. Fremier, Hannah Gosnell, Edella C. Schlager
Balancing Stability And Flexibility In Adaptive Governance: An Analysis Of Tools Available In U.S. Environmental Law, Robin Kundis Craig, Ahjond S. Garmestani, Craig R. Allen, Craig Anthony (Tony) Arnold, Hannah E. Birge, Hannah Birge, Daniel A. Decaro, Alexander K. Fremier, Alexander K. Fremier, Hannah Gosnell, Edella C. Schlager
United States Geological Survey: Staff Publications
Adaptive governance must work “on the ground,” that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased …
Smartphone Technologies And Bayesian Networks To Assess Shorebird Habitat Selection, Sara L. Zeigler, E. Robert Thieler, Benjamin T. Gutierrez, Nathaniel G. Plant, Megan Hines, James D. Fraser, Daniel H. Catlin
Smartphone Technologies And Bayesian Networks To Assess Shorebird Habitat Selection, Sara L. Zeigler, E. Robert Thieler, Benjamin T. Gutierrez, Nathaniel G. Plant, Megan Hines, James D. Fraser, Daniel H. Catlin
United States Geological Survey: Staff Publications
Understanding patterns of habitat selection across a species’ geographic distribution can be critical for adequately managing populations and planning for habitat loss and related threats. However, studies of habitat selection can be time consuming and expensive over broad spatial scales, and a lack of standardized monitoring targets or methods can impede the generalization of site-based studies. Our objective was to collaborate with natural resource managers to define available nesting habitat for piping plovers (Charadrius melodus) throughout their U.S. Atlantic coast distribution from Maine to North Carolina, with a goal of providing science that could inform habitat management in …
Camera System Considerations For Geomorphic Applications Of Sfm Photogrammetry, Adam R. Mosbrucker, Jon J. Major, Kurt R. Spicer, John Pitlick
Camera System Considerations For Geomorphic Applications Of Sfm Photogrammetry, Adam R. Mosbrucker, Jon J. Major, Kurt R. Spicer, John Pitlick
United States Geological Survey: Staff Publications
The availability of high-resolution, multi-temporal, remotely sensed topographic data is revolutionizing geomorphic analysis. Three-dimensional topographic point measurements acquired from structure-from-motion (SfM) photogrammetry have been shown to be highly accurate and cost-effective compared to laser-based alternatives in some environments. Use of consumer-grade digital cameras to generate terrain models and derivatives is becoming prevalent within the geomorphic community despite the details of these instruments being largely overlooked in current SfM literature.
A practical discussion of camera system selection, configuration, and image acquisition is presented. The hypothesis that optimizing source imagery can increase digital terrain model (DTM) accuracy is tested by evaluating accuracies …
Channel-Planform Evolution In Four Rivers Of Olympic National Park, Washington, Usa: The Roles Of Physical Drivers And Trophic Cascades, Amy E. East, Kurt J. Jenkins, Patricia J. Happe, Jennifer A. Bountry, Timothy J. Beechie, Mark C. Mastin, Joel B. Sankey, Timothy J. Randle
Channel-Planform Evolution In Four Rivers Of Olympic National Park, Washington, Usa: The Roles Of Physical Drivers And Trophic Cascades, Amy E. East, Kurt J. Jenkins, Patricia J. Happe, Jennifer A. Bountry, Timothy J. Beechie, Mark C. Mastin, Joel B. Sankey, Timothy J. Randle
United States Geological Survey: Staff Publications
Identifying the relative contributions of physical and ecological processes to channel evolution remains a substantial challenge in fluvial geomorphology. We use a 74-year aerial photographic record of the Hoh, Queets, Quinault, and Elwha Rivers, Olympic National Park, Washington, USA, to investigate whether physical or trophic-cascade-driven ecological factors – excessive elk impacts after wolves were extirpated a century ago – are the dominant drivers of channel planform in these gravel-bed rivers.We find that channel width and braiding show strong relationships with recent flood history. All four rivers widened significantly after having been relatively narrow in the 1970s, consistent with increased flood …
Semi-Arid Grassland Bird Responses To Patch-Burn Grazing And Drought, Susan K. Skagen, David J. Augustine, Justin D. Derner
Semi-Arid Grassland Bird Responses To Patch-Burn Grazing And Drought, Susan K. Skagen, David J. Augustine, Justin D. Derner
United States Geological Survey: Staff Publications
As grassland birds of central North America experience steep population declines with changes in land use, management of remaining tracts becomes increasingly important for population viability. The integrated use of fire and grazing may enhance vegetation heterogeneity and diversity in breeding birds, but the subsequent effects on reproduction are unknown. We examined the influence of patch-burn grazing management in shortgrass steppe in eastern Colorado on habitat use and reproductive success of 3 grassland bird species, horned lark (Eremophila alpestris), lark bunting (Calamospiza melanocorys), and McCown’s longspur (Rhynchophanes mccownii), at several spatial scales during 2011 …
Lack Of Observed Movement Response To Lead Exposure Of California Condors, Sharon A. Poessel, Joseph Brandt, Linda Uyeda, Molly Astell, Todd E. Katzner
Lack Of Observed Movement Response To Lead Exposure Of California Condors, Sharon A. Poessel, Joseph Brandt, Linda Uyeda, Molly Astell, Todd E. Katzner
United States Geological Survey: Staff Publications
Lead poisoning is an important conservation concern for wildlife, and scavenging birds are especially at risk from consumption of carcasses of animals killed with lead ammunition. Because current methods to identify lead exposure require animal capture and blood collection, management would benefit from the development of a less costly and noninvasive behavioral test for illness in wild animals. We attempted to design such a test to identify lead exposure in California condors (Gymnogyps californianus) that we tracked with global positioning system (GPS) telemetry in southern California, USA, 2013–2016. We measured blood-lead concentrations in tracked birds and expected that …
Effects Of Industrial And Investigator Disturbance On Arctic-Nesting Geese, Brandt W. Meixell, Paul L. Flint
Effects Of Industrial And Investigator Disturbance On Arctic-Nesting Geese, Brandt W. Meixell, Paul L. Flint
United States Geological Survey: Staff Publications
Oil and gas development on the Arctic Coastal Plain (ACP) of Alaska, USA may have effects on Arctic-nesting birds. To estimate effects of industrial activity and investigator disturbance on avian productivity, we monitored nests of greater white-fronted geese (Anser albifrons) with digital cameras and periodic nest visits during 2013–2014 at 2 sites on the ACP. A disturbed site was adjacent to human-made infrastructure and industrial clean-up activities initiated at the onset of the study and a control site was >2 km from sources of industrial disturbance. We assessed variation in estimates of incubation constancy, nest survival, and predator …
Simulating The Effects Of Management Practices On Cropland Soilorganic Carbon Changes In The Temperate Prairies Ecoregion Of Theunited States From 1980 To 2012, Zhengpeng Li, Shuguang Liu, Zhengxi Tan, Terry L. Sohl, Yiping Wu
Simulating The Effects Of Management Practices On Cropland Soilorganic Carbon Changes In The Temperate Prairies Ecoregion Of Theunited States From 1980 To 2012, Zhengpeng Li, Shuguang Liu, Zhengxi Tan, Terry L. Sohl, Yiping Wu
United States Geological Survey: Staff Publications
Understanding the effects of management practices on soil organic carbon (SOC) is important for design-ing effective policies to mitigate greenhouse gas emissions in agriculture. In the Midwest United States,management practices in the croplands have been improved to increase crop production and reduce SOCloss since the 1980s. Many studies of SOC dynamics in croplands have been performed to understandthe effects of management, but the results are still not conclusive. This study quantified SOC dynam-ics in the Midwest croplands from 1980 to 2012 with the General Ensemble Biogeochemical ModellingSystem (GEMS) and available management data. Our results showed that the total SOC in …
Underground Structures, Rock Structures And Rock Mechanics From Ancient Era To The Modern Age, Ebru Akiş, Özgür Satici
Underground Structures, Rock Structures And Rock Mechanics From Ancient Era To The Modern Age, Ebru Akiş, Özgür Satici
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Usage of underground space is an old habit for human beings since ancient era. Our ancestors have used caves as a shelter for protection from the wildlife and nature, and they excavated caves to extract valuable minerals. They also used them as sanctuaries, tombs or for storage of goods. In addition, they built tunnels to be used as assault systems or to underpass fortifications during ancient warfare. Later on, tunnels were driven to supply water to the towns or to protect the towns from floods. They also built them for communication purposes. Though not knowing the exact time when they …
Wellbore Stability Evaluation For Mishrif Formation, Ethar H.K. Alkamil, Husam R. Abbood, Ralph E. Flori, Andreas Eckert
Wellbore Stability Evaluation For Mishrif Formation, Ethar H.K. Alkamil, Husam R. Abbood, Ralph E. Flori, Andreas Eckert
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
During drilling operations for the E oilfield in the Mishrif formation in southern Iraq, stuck pipe has been identified as a significant geomechanical problem for several wells. In this study, a 1-D mechanical earth model (MEM) of the Mishrif formation is compiled based on its state of stress and rock strength parameters and is utilized to assess the contribution of borehole collapse leading to the stuck pipe problems. The MEM model is based on the principal in situ stresses and their orientation obtained from wireline logs measurements, measuring while drilling (MWD), and leak off test (LOT). Rock strength properties are …
Shocked Quartz Distribution, Andrew Mason
Shocked Quartz Distribution, Andrew Mason
UCARE: Research Products
Shocked quartz is typically used to test if sites experienced a meteorite impact in the past, however, sediment is readily transported by both earthly and extraterrestrial processes that blur the lines of where impact sites are on earth. The specific deformations in the clasts themselves reveal much about their origin and present location.
Re-Evaluating The Tectonic Model For The Arbuckle Mountains, Oklahoma By Spatial And Geometric Analysis Of Stratigraphic And Structural Trends, Dakota James Kolb
Re-Evaluating The Tectonic Model For The Arbuckle Mountains, Oklahoma By Spatial And Geometric Analysis Of Stratigraphic And Structural Trends, Dakota James Kolb
Electronic Theses and Dissertations
Understanding the spatial distribution and geometric relations between stratigraphy and structural features can allow for a more accurate tectonic timeline to be considered for not only the Arbuckle Mountains but for the assembly of modern North America. The Arbuckle Mountains in south central Oklahoma exhibit structurally complex stratigraphy associated with regional features like the Southern Oklahoma Aulacogen, the Arbuckle Anticline and the Washita Valley fault. Camp Classen YMCA and Turner Falls city park in Davis, OK, hosts observed, but largely unmapped, small scale structural features that best represent the magnitude of deformation. The goal of this study was to determine …
Weathering And Erosion Of Fractured Bedrock Systems, Marina I. Lebedeva, Susan L. Brantley
Weathering And Erosion Of Fractured Bedrock Systems, Marina I. Lebedeva, Susan L. Brantley
United States Geological Survey: Staff Publications
We explore the contribution of fractures (joints) in controlling the rate of weathering advance for a low-porosity rock by using methods of homogenization to create averaged weathering equations. The rate of advance of the weathering front can be expressed as the same rate observed in non-fractured media (or in an individual block) divided by the volume fraction of nonfractured blocks in the fractured parent material. In the model, the parent has fractures that are filled with a more porous material that contains only inert or completely weathered material. The low-porosity rock weathers by reaction-transport processes. As observed in field systems, …
Natural And Human-Induced Variability In Barrier-Island Response To Sea Level Rise, Jennifer Miselis, Jorge Lorenzo Trueba
Natural And Human-Induced Variability In Barrier-Island Response To Sea Level Rise, Jennifer Miselis, Jorge Lorenzo Trueba
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
Storm-driven sediment fluxes onto and behind barrier islands help coastal barrier systems keep pace with sea level rise (SLR). Understanding what controls cross-shore sediment flux magnitudes is critical for making accurate forecasts of barrier response to increased SLR rates. Here, using an existing morphodynamic model for barrier island evolution, observations are used to constrain model parameters and explore potential variability in future barrier behavior. Using modeled drowning outcomes as a proxy for vulnerability to SLR, 0%, 28%, and 100% of the barrier is vulnerable to SLR rates of 4, 7, and 10 mm/yr, respectively. When only overwash fluxes are increased …
Explaining Creep-Like Deformation In The Marmara Sea: Results From Avo-Derived Vp/Vs And Pore Pressure Analysis, Rahmi M. Bolat
Explaining Creep-Like Deformation In The Marmara Sea: Results From Avo-Derived Vp/Vs And Pore Pressure Analysis, Rahmi M. Bolat
Earth Sciences Theses and Dissertations
Recent studies suggest that high pore pressures have caused seafloor creep-like deformation and slope failure in the Marmara Sea (e.g. Shillington et al., 2012). Stratigraphic analysis provides evidence for creep-like deformation in Marmara Sea sediments, however, no detailed quantitative geophysical analysis has been conducted to determine whether elevated fluid pressures exist in the Marmara Sea sediments today, or if these sediments are potentially near-critically stressed. If fluid pressures are high and the sediments are close to failure, only minor ground accelerations from earthquakes along the active Northern Anatolian Fault might trigger failure. For this study, I use high resolution multichannel …
Zircon As A Proxy For "Taking The Temperature" Of Granites: An Example Using Zircon Thermometry Applied To Grenvillian Mid-Crustal Magmas In The Blue Ridge Province, Virginia, Samantha Rae Burk
Theses and Dissertations--Earth and Environmental Sciences
The Grenville orogeny was a protracted (~200 m.y.) series of “hot” magmatic- metamorphic events that contributed to the growth of the Laurentian margin in the late Mesoproterozoic. The granites contain remarkably high Zr content, lack xenocrysts, and become zircon saturated at high temperatures, which are all unusual for felsic magmas. The “hot Grenville granite” hypothesis is tested and use of high-Zr granitoids as potential zones of crustal magma generation through: U-Pb geochronology and cathodoluminescence imaging to assess inherited zircon components; quantitative modeling of zircon crystallization history using rhyolite-MELTS; and Ti-in-zircon thermometry. U-Pb zircon ages for two samples from the Virginia …
Callianassid Shrimp Diversity Around San Salvador Island, Bahamas: Why Marine Biologists And Geologists Should Care, H. Allen Curran, Koji Seike
Callianassid Shrimp Diversity Around San Salvador Island, Bahamas: Why Marine Biologists And Geologists Should Care, H. Allen Curran, Koji Seike
Geosciences: Faculty Publications
Reprinted from: Carol L. Landry, Lee J. Florea, & Daniel S. Kjar (eds.), Proceedings of the 1st Joint Symposium on the Natural History and Geology of The Bahamas: San Salvador, Gerace Research Centre
Post-Rift Magmatic Evolution Of The Eastern North American “Passive-Aggressive” Margin, Sarah E. Mazza, Esteban Gazel, Elizabeth A. Johnson, Michael Bizimis, Ryan Mcaleer, C. Berk Biryol
Post-Rift Magmatic Evolution Of The Eastern North American “Passive-Aggressive” Margin, Sarah E. Mazza, Esteban Gazel, Elizabeth A. Johnson, Michael Bizimis, Ryan Mcaleer, C. Berk Biryol
Geosciences: Faculty Publications
Understanding the evolution of passive margins requires knowledge of temporal and chemical constraints on magmatism following the transition from supercontinent to rifting, to post-rifting evolution. The Eastern North American Margin (ENAM) is an ideal study location as several magmatic pulses occurred in the 200 My following rifting. In particular, the Virginia-West Virginia region of the ENAM has experienced two postrift magmatic pulses at ∼152 Ma and 47 Ma, and thus provides a unique opportunity to study the long-term magmatic evolution of passive margins. Here we present a comprehensive set of geochemical data that includes new Ar/ Ar ages, major and …
St. Louis Area Earthquake Hazards Mapping Project: Seismic And Liquefaction Hazard Maps, Chris H. Cramer, Robert A. Bauer, Jaewon Chung, J. David Rogers, Larry Pierce, Vicki Voigt, Brad Mitchell, David Gaunt, Robert A. Williams, David J. Hoffman, Gregory L. Hempen, Phyllis J. Steckel, Oliver Salz Boyd, Connor M. Watkins, Kathleen B. Tucker, Natasha S. Mccallister
St. Louis Area Earthquake Hazards Mapping Project: Seismic And Liquefaction Hazard Maps, Chris H. Cramer, Robert A. Bauer, Jaewon Chung, J. David Rogers, Larry Pierce, Vicki Voigt, Brad Mitchell, David Gaunt, Robert A. Williams, David J. Hoffman, Gregory L. Hempen, Phyllis J. Steckel, Oliver Salz Boyd, Connor M. Watkins, Kathleen B. Tucker, Natasha S. Mccallister
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We present probabilistic and deterministic seismic and liquefaction hazard maps for the densely populated St. Louis metropolitan area that account for the expected effects of surficial geology on earthquake ground shaking. Hazard calculations were based on a map grid of 0.005°, or about every 500 m, and are thus higher in resolution than any earlier studies. To estimate ground motions at the surface of the model (e.g., site amplification), we used a new detailed near-surface shear-wave velocity model in a 1D equivalent- linear response analysis. When compared with the 2014 U.S. Geological Survey (USGS) National Seismic Hazard Model, which uses …