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15330 full-text articles. Page 1 of 348.

Explosive Dome Eruptions Modulated By Periodic Gas-Driven Inflation, Jeffrey B. Johnson, J. J. Lyons, B. J. Andrews, J. M. Lees 2016 Boise State University

Explosive Dome Eruptions Modulated By Periodic Gas-Driven Inflation, Jeffrey B. Johnson, J. J. Lyons, B. J. Andrews, J. M. Lees

Jeffrey Lyons

Volcan Santiaguito (Guatemala) “breathes” with extraordinary regularity as the edifice's conduit system accumulates free gas, which periodically vents to the atmosphere. Periodic pressurization controls explosion timing, which nearly always occurs at peak inflation, as detected with tiltmeters. Tilt cycles in January 2012 reveal regular 26 ± 6 min inflation/deflation cycles corresponding to at least ~101 kg/s of gas fluxing the system. Very long period (VLP) earthquakes presage explosions and occur during cycles when inflation rates are most rapid. VLPs locate ~300 m below the vent and indicate mobilization of volatiles, which ascend at ~50 m/s. Rapid gas ...


Species Diversification In Eriogonum Umbellatum Var. Aureum, Majus, And Umbellatum In The Colorado Rocky Mountains, Erica Arcibal 2016 University of Northern Colorado

Species Diversification In Eriogonum Umbellatum Var. Aureum, Majus, And Umbellatum In The Colorado Rocky Mountains, Erica Arcibal

Ursidae: The Undergraduate Research Journal at the University of Northern Colorado

No abstract provided.


Recovery Of Acid Sulfate Sediments In The Lower Lakes, Leigh A. Sullivan, Nicholas J. Ward, Mark A. Rosicky, S Li, Richard T. Bush, Diane M. Fyfe, Michelle Bush, N Toppler 2016 Southern Cross University

Recovery Of Acid Sulfate Sediments In The Lower Lakes, Leigh A. Sullivan, Nicholas J. Ward, Mark A. Rosicky, S Li, Richard T. Bush, Diane M. Fyfe, Michelle Bush, N Toppler

Adjunct Professor Richard T Bush

No abstract provided.


Recovery Of Acid Sulfate Sediments In The Lower Lakes, Leigh A. Sullivan, Nicholas J. Ward, Mark A. Rosicky, S Li, Richard T. Bush, Diane M. Fyfe, Michelle Bush, N Toppler 2016 Southern Cross University

Recovery Of Acid Sulfate Sediments In The Lower Lakes, Leigh A. Sullivan, Nicholas J. Ward, Mark A. Rosicky, S Li, Richard T. Bush, Diane M. Fyfe, Michelle Bush, N Toppler

Dr Nicholas J Ward

No abstract provided.


Recovery Of Acid Sulfate Sediments In The Lower Lakes, Leigh A. Sullivan, Nicholas J. Ward, Mark A. Rosicky, S Li, Richard T. Bush, Diane M. Fyfe, Michelle Bush, N Toppler 2016 Southern Cross University

Recovery Of Acid Sulfate Sediments In The Lower Lakes, Leigh A. Sullivan, Nicholas J. Ward, Mark A. Rosicky, S Li, Richard T. Bush, Diane M. Fyfe, Michelle Bush, N Toppler

Adjunct Professor Leigh A Sullivan

No abstract provided.


Trajectory Analysis Of Black Carbon In The Arctic Region, Kimberly Gottschalk 2016 Portland State University

Trajectory Analysis Of Black Carbon In The Arctic Region, Kimberly Gottschalk

PSU McNair Scholars Online Journal

Black carbon (BC) is a troubling particulate. Commonly known as soot, BC forms through the incomplete combustion of fossil fuels, biofuels, and biomass. It has a very low albedo compared to natural particulates making it a very efficient absorber of solar radiation. As BC is deposited on snow and ice, albedo is decreased - enhancing solar heating and increasing meltwater production. With rising air temperatures, melting rates of polar ice are increasing and are being enhanced by BC, leading to accelerated global sea level rise.

This study aimed to document sources and deposition areas of BC in the Arctic. Utilizing HySplit ...


Teaching Big History, Richard B. Simon, Mojgan Behmand, Thomas Burke, Esther Quaedackers, Seohyung Kim, Kiowa Bower, Neal Wolfe, James B. Cunningham, Cynthia Taylor, Martin Anderson, J. Daniel May, Philip Novak, Debbie Daunt, Jaime Castner, Ethan Annis, Amy E. Gilbert, Anne Reid, Suzanne Roybal, Alan Schut, Cynthia Brown, Harlan Stelmach 2016 Department of Literature and Languages, Dominican University of California

Teaching Big History, Richard B. Simon, Mojgan Behmand, Thomas Burke, Esther Quaedackers, Seohyung Kim, Kiowa Bower, Neal Wolfe, James B. Cunningham, Cynthia Taylor, Martin Anderson, J. Daniel May, Philip Novak, Debbie Daunt, Jaime Castner, Ethan Annis, Amy E. Gilbert, Anne Reid, Suzanne Roybal, Alan Schut, Cynthia Brown, Harlan Stelmach

Harlan Stelmach

Big History is a new field on a grand scale: it tells the story of the universe over time through a diverse range of disciplines that spans cosmology, physics, chemistry, astronomy, geology, evolutionary biology, anthropology, and archaeology, thereby reconciling traditional human history with environmental geography and natural history.Weaving the myriad threads of evidence-based human knowledge into a master narrative that stretches from the beginning of the universe to the present, the Big History framework helps students make sense of their studies in all disciplines by illuminating the structures that underlie the universe and the connections among them.Teaching Big ...


Agenda: Coping With Water Scarcity In River Basins Worldwide: Lessons Learned From Shared Experiences, University of Colorado Boulder. Getches-Wilkinson Center for Natural Resources, Energy, and the Environment 2016 University of Colorado Law School

Agenda: Coping With Water Scarcity In River Basins Worldwide: Lessons Learned From Shared Experiences, University Of Colorado Boulder. Getches-Wilkinson Center For Natural Resources, Energy, And The Environment

Coping with Water Scarcity in River Basins Worldwide: Lessons Learned from Shared Experiences (Martz Summer Conference, June 9-10)

Water scarcity is increasingly dominating headlines throughout the world. In the southwestern USA, the looming water shortages on the Colorado River system and the unprecedented drought in California are garnering the greatest attention. Similar stories of scarcity and crisis can be found across the globe, suggesting an opportunity for sharing lessons and innovations. For example, the Colorado River and Australia's Murray-Darling Basin likely can share many lessons, as both systems were over-allocated, feature multiple jurisdictions, face similar climatic risks and drought stresses, and struggle to balance human demands with environmental needs. In this conference we cast our net broadly ...


Shell Bluff – A Fossiliferous Ridge, The Site Of The Extinct Oyster Crassostrea Gigantissima And History Of Its Identification, elliott o. edwards jr. 2016 Bartram Trail Conference

Shell Bluff – A Fossiliferous Ridge, The Site Of The Extinct Oyster Crassostrea Gigantissima And History Of Its Identification, Elliott O. Edwards Jr.

Georgia Journal of Science

Shell Bluff is described by geologists as stratigraphically one of the most important exposures in the Georgia Coastal Plain because the bluff is home to the large oyster, Crassostrea gigantissima, now extinct. Native Americans inhabited this area prior to Hernando DeSoto and his men who visited the area in 1540. They were probably the first Europeans to visit Shell Bluff. John and son William Bartram visited the bluff in 1764 and John described the bluff in his journal and the existence of large oysters. The British naturalist, John Finch, described a fossil oyster taken from the site in 1824 as ...


A Modified Delay-Time Method For Statics Estimation With The Virtual Refraction, T. Dylan Mikesell, Kasper van Wijk, Elmer Ruigrok, Andrew Lamb, Thomas E. Blum 2016 Boise State University

A Modified Delay-Time Method For Statics Estimation With The Virtual Refraction, T. Dylan Mikesell, Kasper Van Wijk, Elmer Ruigrok, Andrew Lamb, Thomas E. Blum

Dylan Mikesell

Topography and near-surface heterogeneities lead to traveltime perturbations in surface land-seismic experiments. Usually, these perturbations are estimated and removed prior to further processing of the data. A common technique to estimate these perturbations is the delay-time method. We have developed the “modified delay-time method,” wherein we isolate the arrival times of the virtual refraction and estimate receiver-side delay times. The virtual refraction is a spurious arrival found in wavefields estimated by seismic interferometry. The new method removes the source term from the delay-time equation, is more robust in the presence of noise, and extends the lateral aperture compared to the ...


The Terroir Of Pinot Noir Wine In The Willamette Valley, Oregon €“ A Broad Analysis Of Vineyard Soils, Grape Juice And Wine Chemistry, Kathryn Nora Barnard 2016 Portland State University

The Terroir Of Pinot Noir Wine In The Willamette Valley, Oregon €“ A Broad Analysis Of Vineyard Soils, Grape Juice And Wine Chemistry, Kathryn Nora Barnard

Dissertations and Theses

Terroir is determined by a combination of factors in the vineyard including the grape varietal, geology and soil, soil hydrology, physiography, and climate. Although most studies have examined regional differences in wine flavors and associated provenance of wine based on chemistry, few have examined the chemistry of the soil and the ability to trace that chemistry to grape juice and, finally, to the wine. This dissertation examines what soil physical and chemical differences specific to this region might influence grape juice chemistry and wine chemistry.

Wine-grapes in the Willamette Valley, Oregon, are grown on three major soil parent materials: volcanic ...


Quasi-Static Eocene–Oligocene Climate In Patagonia Promotes Slow Faunal Evolution And Mid-Cenozoic Global Cooling, Matthew J. Kohn, Caroline A.E. Strömberg, Richard H. Madden, Regan E. Dunn, Samantha L. Evans, Alma Palacios, Alfredo A. Carlini 2016 Boise State University

Quasi-Static Eocene–Oligocene Climate In Patagonia Promotes Slow Faunal Evolution And Mid-Cenozoic Global Cooling, Matthew J. Kohn, Caroline A.E. Strömberg, Richard H. Madden, Regan E. Dunn, Samantha L. Evans, Alma Palacios, Alfredo A. Carlini

Matthew J. Kohn

New local/regional climatic data were compared with floral and faunal records from central Patagonia to investigate how faunas evolve in the context of local and global climates. Oxygen isotope compositions of mammal fossils between c. 43 and 21 Ma suggest a nearly constant mean annual temperature of 16 ± 3 °C, consistent with leaf physiognomic and sea surface studies that imply temperatures of 16–18 °C. Carbon isotopes in tooth enamel track atmospheric δ13C, but with a positive deviation at 27.2 Ma, and a strong negative deviation at 21 Ma. Combined with paleosol characteristics and reconstructed Leaf ...


Structure And Geochronology Of The White Fork Pluton, Southern Sierra Nevada, Ian Richard Mahaffey 2016 California Polytechnic State University, San Luis Obispo

Structure And Geochronology Of The White Fork Pluton, Southern Sierra Nevada, Ian Richard Mahaffey

Natural Resources Management and Environmental Sciences

The Sierra Nevada batholith represents an archetypal continental arc, although the style of deformation throughout the history of the arc is only poorly understood, in part due to the voluminous nature of Late Cretaceous magmatism that has overprinted earlier structures. The purpose of this study is to gain a better understanding of pre-Late Cretaceous deformation in the Sierra Nevada batholith through a structural and geochronological study of the Jurassic White Fork pluton. A Jurassic age for the White Fork pluton is indicated by its inclusion of numerous 148 Ma Independence dikes, and geochronology on the White Fork pluton is limited ...


Quartz Crystal Preferred Orientation And Recrystallization Patterns From Naturally Deformed Rocks Under Constriction, Riley Quine 2016 California Polytechnic State University, San Luis Obispo

Quartz Crystal Preferred Orientation And Recrystallization Patterns From Naturally Deformed Rocks Under Constriction, Riley Quine

Materials Engineering

This study analyzes crystal preferred orientation (CPO) patterns within constrictional quartz-rich gneisses. Quartz deformation and CPO patterns are an area of interest because quartz is one of the most prevalent minerals in earth's crust. Understanding the typical way that quartz crystals reorient under different states of strain can provide geologists with an additional tool for understanding paleo-strain. Temperature and strain geometry are two dominant factors that control the orientation of quartz crystals within a rock. Temperature determines which slip planes are active and slip planes typically reorient so that they are perpendicular to maximum stress. Previous workers have suggested ...


Monitoring Southwest Greenland’S Ice Sheet Melt With Ambient Seismic Noise, Aurélien Mordret, T. Dylan Mikesell, Christopher Harig, Bradley P. Lipovsky, Germán A. Prieto 2016 Massachusetts Institute of Technology

Monitoring Southwest Greenland’S Ice Sheet Melt With Ambient Seismic Noise, Aurélien Mordret, T. Dylan Mikesell, Christopher Harig, Bradley P. Lipovsky, Germán A. Prieto

Dylan Mikesell

The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth’s crust, as measured with the correlation of seismic noise, may be used to infer seasonal ...


Distributed Modeling Of Ablation (1996–2011) And Climate Sensitivity On The Glaciers Of Taylor Valley, Antarctica, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston 2016 Los Alamos National Laboratory

Distributed Modeling Of Ablation (1996–2011) And Climate Sensitivity On The Glaciers Of Taylor Valley, Antarctica, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston

Andrew G. Fountain

The McMurdo Dry Valleys of Antarctica host the coldest and driest ecosystem on Earth, which is acutely sensitive to the availability of water coming from glacial runoff. We modeled the spatial variability in ablation and assessed climate sensitivity of the glacier ablation zones using 16 years of meteorological and surface mass-balance observations collected in Taylor Valley. Sublimation was the primary form of mass loss over much of the ablation zones, except for near the termini where melt, primarily below the surface, dominated. Microclimates in ~10 m scale topographic basins generated melt rates up to ten times higher than over smooth ...


The Need To Adapt The Exploration Model From The Oil Patch To Contaminated-Site Characterization: A Case From Hill Afb, Utah, Usa, John H. Bradford, Esther Babcock 2016 Boise State University

The Need To Adapt The Exploration Model From The Oil Patch To Contaminated-Site Characterization: A Case From Hill Afb, Utah, Usa, John H. Bradford, Esther Babcock

John H. Bradford

For decades, the oil industry has employed a working model for hydrocarbon exploration in which large-scale geophysical surveys are undertaken prior to a second phase of intensive, targeted drilling. This latter phase may be conducted in conjunction with further focused geophysical studies. The geophysical surveys provide lateral coverage and continuity that are used to drive placement of drilling locations. The reason for this approach is simple: wells are expensive relative to geophysical surveys. Also, practical limits on lateral coverage preclude optimization of exploration targets based on well information alone.


Dissolved Organic Carbon Fluxes From A New England Salt Marsh, Hayley Nicole Schiebel 2016 University of Massachusetts Boston

Dissolved Organic Carbon Fluxes From A New England Salt Marsh, Hayley Nicole Schiebel

Graduate Doctoral Dissertations

Blue carbon systems (mangroves, salt marshes, and seagrass beds) sequester large amounts of carbon via primary productivity and sedimentation. Sequestered carbon can be respired back to the atmosphere, buried for long time periods, or exported (“outwelled”) to adjacent ecosystems. This study estimates the total outwelling of dissolved organic carbon (DOC) from the Neponset Salt Marsh (Boston, Massachusetts) as well as the major plant and sediment processes contributing to the overall flux. The total export was quantified via high-resolution in situ chromophoric dissolved organic matter (CDOM) measurements as a proxy for DOC using 12 years of transect data. Seasonal trends, alternate ...


Trace Element Diffusivities In Bone Rule Out Simple Diffusive Uptake During Fossilization But Explain In Vivo Uptake And Release, Matthew J. Kohn, Randolph J. Moses 2016 Boise State University

Trace Element Diffusivities In Bone Rule Out Simple Diffusive Uptake During Fossilization But Explain In Vivo Uptake And Release, Matthew J. Kohn, Randolph J. Moses

Matthew J. Kohn

Diffusion rates of numerous trace elements in bone at 20 °C were determined using laser-ablation inductively coupled plasma mass spectrometry analysis of experimentally induced diffusion profiles. Diffusivities are about 1 order of magnitude slower than current semiquantitative geochemical views and about 1.5 orders of magnitude faster than indirect radiotracer estimates. Intrabone volume diffusion is too slow and too similar among many elements to explain trace element profiles in young fossils and archeological materials. Diffusivity differences among elements do, however, explain disparate biokinetic washout of Sr vs. Ba and of light vs. heavy rare earth elements (REEs). These results improve ...


Elastic Block Modeling Of Fault Slip Rates Across Southern California, Liam P. DiZio 2016 Macalester College

Elastic Block Modeling Of Fault Slip Rates Across Southern California, Liam P. Dizio

Macalester Journal of Physics and Astronomy

We present fault slip rate estimates for Southern California based on Global Positioning System (GPS) velocity data from the University NAVSTAR Consortium (UNAVCO), the Southern California Earthquake Center (SCEC), and new campaign GPS velocity data from the San Bernardino Mountains and vicinity. Fault slip-rates were calculated using Tdefnode, a program used to model elastic deformation within lithospheric blocks and slip on block bounding faults [2]. Our block model comprised most major faults within Southern California. Tdefnode produced similar slip rate values as other geodetic modeling techniques. The fastest slipping faults are the Imperial fault (37.4±0.1 mm/yr ...


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