Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

2012

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 571 - 600 of 988

Full-Text Articles in Earth Sciences

Two New Species Of Trigonotylus (Hemiptera: Heteroptera: Miridae: Stenodemini) From Western Canada And Northwestern United States, G G.E. Scudder, Michael D. Schwartz Jan 2012

Two New Species Of Trigonotylus (Hemiptera: Heteroptera: Miridae: Stenodemini) From Western Canada And Northwestern United States, G G.E. Scudder, Michael D. Schwartz

Green Canyon Environmental Research Area, Logan Utah

No abstract provided.

Go to article

Vent-Fault Spatial Study Of Selected Volcanic Fields Of Southwestern North America And Mexico, Michelle Leonard Jan 2012

Vent-Fault Spatial Study Of Selected Volcanic Fields Of Southwestern North America And Mexico, Michelle Leonard

USF Tampa Graduate Theses and Dissertations

Of fundamental concern in volcanic hazard and risk assessment studies of volcanic systems is what role crustal structures might play in the ascent of magma through the crust. What are the processes that govern the spatial distribution and timing of eruptions, especially in populated areas or near sensitive facilities? Many studies have drawn the conclusion that faults play a critical role as easily–exploitable crustal weaknesses along which magma can ascend. Great care must be used when assuming a causative relationship between patterns of vents and faults especially when such relationships may be incorporated into hazard assessment models or other forecasting …

Go to article

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson Jan 2012

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson

CGISS Publications and Presentations

Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt-driven elevation changes on the Greenland ice sheet. This is especially true in Greenland’s percolation zone, where firn density profiles are poorly documented because few ice cores are extracted in regions with surface melt. We used georadar to investigate firn density variations with depth along a ~70 km transect through a portion of the accumulation area in western Greenland that partially melts. We estimated electromagnetic wave velocity by inverting reflection traveltimes picked from common midpoint gathers. We followed a procedure designed to find the simplest velocity …

Go to article

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson Jan 2012

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson

Geosciences Faculty Publications

Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt-driven elevation changes on the Greenland ice sheet. This is especially true in Greenland’s percolation zone, where firn density profiles are poorly documented because few ice cores are extracted in regions with surface melt.We used geoader to investigate firn density variations with depth along an about 70 km transect through a portion of the accumulation area in western Greenland that partially melts. We estimated electromagnetic wave velocity by inverting reflection travel times picked from common midpoint gathers. We followed a procedure designed to find the simplest …

Go to article

Thermal Tracking Of Meltwater Retention In Greenland’S Accumulation Area, Neil F. Humphrey, Joel T. Harper, W. Tad Pfeffer Jan 2012

Thermal Tracking Of Meltwater Retention In Greenland’S Accumulation Area, Neil F. Humphrey, Joel T. Harper, W. Tad Pfeffer

Geosciences Faculty Publications

Poorly understood processes controlling retention of meltwater in snow and firn have important implications for Greenland Ice Sheet’s mass balance and flow dynamics. Here we present results from a 3 year (2007-2009) field campaign studying firn thermal profiles and density structure along an 85 km transect of the percolation zone of west Greenland. We installed one or two thermistor strings at 14 study sites, each string having 32 sensors spaced between 0 and 10 m depth. Data from our network of over 500 sensors were collected at 15-60 min intervals for 1-2 years, thereby recording the thermal signature of meltwater …

Go to article

The Emergency Mind: How We Adjust To And Cope With Living In Dangerous Places, Matt Davis Jan 2012

The Emergency Mind: How We Adjust To And Cope With Living In Dangerous Places, Matt Davis

Collected Faculty Scholarship

No abstract provided.

Go to article

A Global Assessment Of The Water Footprint Of Farm Animal Products, Mesfin Mekonnen, Arjen Y. Hoekstra Jan 2012

A Global Assessment Of The Water Footprint Of Farm Animal Products, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

The increase in the consumption of animal products is likely to put further pressure on the world’s freshwater resources. This paper provides a comprehensive account of the water footprint of animal products, considering different production systems and feed composition per animal type and country. Nearly one-third of the total water footprint of agriculture in the world is related to the production of animal products. The water footprint of any animal product is larger than the water footprint of crop products with equivalent nutritional value. The average water footprint per calorie for beef is 20 times larger than for cereals and …

Go to article

A Mineralogical Study Of Late Bronze Age Ceramics From Palatca (Transylvania, Romania), Lucretia M. Ghergari, Carmen Stâncel Jan 2012

A Mineralogical Study Of Late Bronze Age Ceramics From Palatca (Transylvania, Romania), Lucretia M. Ghergari, Carmen Stâncel

Studia UBB Geologia

Our paper studies the mineralogical and petrographical characteristics of 28 ceramic fragments that were excavated in the village of Palatca, Transylvania (Romania). Optical microscopy, X-Ray powder diffraction (XRD), scanning electron microscopy (SEM), grain size analyses, and porosity measurements were used to investigate the samples. Our objective was to describe or reconstruct the corresponding products and to elucidate the manufacturing process, the firing techniques, and the transformation pathways. Based on our results, we conclude that the Late Bronze Age ceramics (1600-1300 BC) were produced from clay and temper material such as river sand and ceramoclasts. It has been modeled by hand …

Go to article

Chemical And Isotopic Evaluation Of Sulfur Sources And Cycling In The Pecos River, New Mexico, Usa, Fasong Yuan, Bernhard Mayer Jan 2012

Chemical And Isotopic Evaluation Of Sulfur Sources And Cycling In The Pecos River, New Mexico, Usa, Fasong Yuan, Bernhard Mayer

Biological, Geological, and Environmental Faculty Publications

The use of stable isotopes in studies of watershed biogeochemical processes has increased greatly throughout the last several decades. Much of the sulfur cycling research has addressed the influence of changes in atmospheric acid deposition on sulfur dynamics in temperate ecosystems. Little is known about sulfur cycling in dryland ecosystems such as those in the American Southwest. To identify the sources and assess the cycling of sulfur in dryland ecosystems, chemical and isotopic compositions of water were measured on samples collected from the Pecos River (New Mexico, USA) during a reconnaissance survey in spring 2010. Based on the chemical and …

Go to article

Mineralogical Composition Of Diabase And Altered Dolostone From The St. Francois Mountains Near Annapolis, Missouri, Usa, Jessica K. Walter, C. Renee Rohs Jan 2012

Mineralogical Composition Of Diabase And Altered Dolostone From The St. Francois Mountains Near Annapolis, Missouri, Usa, Jessica K. Walter, C. Renee Rohs

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Dolostones of Cambrian and Ordovician age are found in the St. Francois Mountains on the Ozark Plateau in southeastern Missouri and often lie unconformably over Precambrian basement rocks due to the paleo-topography. In some areas, there is distinct evidence of alteration and mineralization within the dolostones. One such location is found near Annapolis, Missouri where nearly all of the original dolomitic material is replaced with quartz. A diabase dike is in close proximity to the silicified dolostone and may have provided the conduit for fluids during alteration. The purpose of this study was to examine samples from the relatively unaltered …

Go to article

Tools Of The Geology Trade And Their Origin, Dan Merriam, Walter Youngquist Jan 2012

Tools Of The Geology Trade And Their Origin, Dan Merriam, Walter Youngquist

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Tools of the trade help a geologist in the field to measure, describe, and record data about rocks and their position and spatial relationships. We explore some of the trademark tools of a geologist and the origin of each tool.

Go to article

The Compass, Volume 1, Number 2, 1920 Jan 2012

The Compass, Volume 1, Number 2, 1920

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

Go to article

Acknowledgements, Larry E. Davis Jan 2012

Acknowledgements, Larry E. Davis

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

Go to article

The Compass: A Shifting Paradigm, Larry E. Davis Jan 2012

The Compass: A Shifting Paradigm, Larry E. Davis

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

Go to article

Major Milestones In The Development Of Sigma Gamma Epsilon's Core Traditions, Richard L. Ford Jan 2012

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.

Go to article

Extent And Mechanism Of Footwall Shear Adjacent To The Ruby's Inn Thrust Fault, Southern Utah, Skyler B. May, Roger E. Leavitt, John S. Maclean Jan 2012

Extent And Mechanism Of Footwall Shear Adjacent To The Ruby's Inn Thrust Fault, Southern Utah, Skyler B. May, Roger E. Leavitt, John S. Maclean

The Compass: Earth Science Journal of Sigma Gamma Epsilon

The Ruby’s Inn Thrust, located in the Bryce Canyon region, is an uncharacteristic demonstration of a south-directed shortening episode located near the predominately east-directed contractional structures of the Sevier Orogeny. The Paleocene to Eocene Claron Formation in the footwall of the Ruby’s Inn Thrust contains conjugate shear structures and vertical fault planes with slickensides and slickenlines, indicating complex multidirectional shearing. We determined the north-south extent of a broad shear zone along a traverse immediately west of Bryce Canyon National Park, and shearing intensifies slowly from the main thrust at the northern end of our traverse to a maximum intensity at …

Go to article

Algal Stromatolites In The Willow River Member Of The Lower Ordovician Shakopee Formation Near Chatfield, Minnesota, Usa, Sophia L. May, Larry E. Davis, David G. Brown Jan 2012

Algal Stromatolites In The Willow River Member Of The Lower Ordovician Shakopee Formation Near Chatfield, Minnesota, Usa, Sophia L. May, Larry E. Davis, David G. Brown

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

Go to article

Mary Anning: Princess Of Palaeontology And Geological Lioness, Larry E. Davis Jan 2012

Mary Anning: Princess Of Palaeontology And Geological Lioness, Larry E. Davis

The Compass: Earth Science Journal of Sigma Gamma Epsilon

On April 17, 2005, delegates at the 39th Biennial Convention of the Society of Sigma Gamma Epsilon passed a motion to include Mary Anning as one of the guiding pillars of geology in the Ritual of the Society. Mary Anning, of Lyme Regis, England, was a 19th century collector of fossils who made significant contributions to the growth of British palaeontology. Among her finds was one of the most complete specimens of Ichthyosaurs found in Britain, as well as the discovery of the first British Plesiosaurus and Dimorphodon (pterosaur). Mary Anning also discovered the true nature of coprolites. …

Go to article

Sigma Gamma Epsilon News And Information Jan 2012

Sigma Gamma Epsilon News And Information

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

Go to article

The Compass, Volume 1, Number 1, 1920 Jan 2012

The Compass, Volume 1, Number 1, 1920

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

Go to article

Ancient Cataclysmic Floods In The Pacific Northwest: Ancestors To The Missoula Floods, Erica Medley Jan 2012

Ancient Cataclysmic Floods In The Pacific Northwest: Ancestors To The Missoula Floods, Erica Medley

Dissertations and Theses

Ancient Cataclysmic Floods were the Ice Age Floods that left erosional and depositional features and preceded the Missoula Floods (15-18,000 ka) in the Pacific Northwest of the United States (Allen et al., 2009). All previously studied ancient sites were visited (14) and new sites (11) were found; four Missoula Flood quarries were also visited; a total of 29 sites were studied in this thesis. The use of calcrete paleosols to provide relative age dates for flood deposits was analyzed in this thesis. Missoula Flood gravel pits were sampled in order to examine the degree of calcrete development in flood deposits …

Go to article

Allen-Carlson, Dawn Elaine (Fa 34), Manuscripts & Folklife Archives Jan 2012

Allen-Carlson, Dawn Elaine (Fa 34), Manuscripts & Folklife Archives

Folklife Archives Finding Aids

Finding aid only for Folklife Archives Project 34. [Dr. Joe Daugherty: collector] Oral history project completed by Dawn Elaine Allen-Carlson concerning the collections of Daugherty for a folk studies class at Western Kentucky University. Contains data sheet, journal, 2 indices, tape summary and transcription.

Go to article

Soil Mapping On A Swanton Pacific Ranch Rangeland, Thomas N. Witman Jan 2012

Soil Mapping On A Swanton Pacific Ranch Rangeland, Thomas N. Witman

Natural Resources Management and Environmental Sciences

Knowledge of soils has become very important in most land based enterprises. The understanding of soils is necessary for all different types of land management projects. The USDA mapped all of the soils in the United States starting in the late 1950’s to provide the necessary information. However because the mappers often times had to map entire counties in short amounts of time ,did not have modern technology, and had rather a vague operating procedure, there was no way to be accurate on the small scaled. To solve this problem I evaluated Dr. Ron Taskey’s landscape hierarchy, a method that …

Go to article

Investigations Into The Degassing And Eruption Mechanisms Of Nyamuragira Volcano, Democratic Republic Of The Congo (Africa) , Elisabet Marie Head Jan 2012

Investigations Into The Degassing And Eruption Mechanisms Of Nyamuragira Volcano, Democratic Republic Of The Congo (Africa) , Elisabet Marie Head

Dissertations, Master's Theses and Master's Reports - Open

One of two active volcanoes in the western branch of the East African Rift, Nyamuragira (1.408ºS, 29.20ºE; 3058 m) is located in the D.R. Congo. Nyamuragira emits large amounts of SO2 (up to ~1 Mt/day) and erupts low-silica, alkalic lavas, which achieve flow rates of up to ~20 km/hr. The source of the large SO2 emissions and pre-eruptive magma conditions were unknown prior to this study, and 1994-2010 lava volumes were only recently mapped via satellite imagery, mainly due to the region’s political instability. In this study, new olivine-hosted melt inclusion volatile (H2O, CO2, S, …

Go to article

Comparison Of Magnetic Properties And Petrography Between Dykes And Lava Flows From La Cienega, New Mexico And Thunder Bay Area, Canada, Elise A. Desplas Jan 2012

Comparison Of Magnetic Properties And Petrography Between Dykes And Lava Flows From La Cienega, New Mexico And Thunder Bay Area, Canada, Elise A. Desplas

Dissertations, Master's Theses and Master's Reports - Open

Data on the evolution of geomagnetic paleointensity are crucial for understanding the geodynamo and Earth’s thermal history. Although basaltic flows are preferred for paleointensity experiments, quickly cooled mafic dykes have also been used. However, the paleointensity values obtained from the dykes are systematically lower than those from lava flows. This bias may originate from the difference in cooling histories and resultant magnetic mineralogies of extrusive and intrusive rocks. To explore this hypothesis, the magnetic mineralogy of two feeder dyke-lave flow systems, from Thunder Bay (Canada) and La Cienega (New-Mexico), has been studied using magnetic and microscopy methods. Within each system, …

Go to article

Lava Discharge Rate Estimates From Thermal Infrared Satellite Data At Pacaya Volcano, Guatemala , Hilary A. Morgan Jan 2012

Lava Discharge Rate Estimates From Thermal Infrared Satellite Data At Pacaya Volcano, Guatemala , Hilary A. Morgan

Dissertations, Master's Theses and Master's Reports - Open

Time-averaged discharge rates (TADR) were calculated for five lava flows at Pacaya Volcano (Guatemala), using an adapted version of a previously developed satellite-based model. Imagery acquired during periods of effusive activity between the years 2000 and 2010 were obtained from two sensors of differing temporal and spatial resolutions; the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Geostationary Operational Environmental Satellites (GOES) Imager. A total of 2873 MODIS and 2642 GOES images were searched manually for volcanic “hot spots”. It was found that MODIS imagery, with superior spatial resolution, produced better results than GOES imagery, so only MODIS data were used …

Go to article

Remote Sensing Of Volcanic Plumes Using The Advanced Spaceborne Thermal Emission And Reflection Radiometer (Aster)., Lorna Alison Henney Jan 2012

Remote Sensing Of Volcanic Plumes Using The Advanced Spaceborne Thermal Emission And Reflection Radiometer (Aster)., Lorna Alison Henney

Dissertations, Master's Theses and Master's Reports - Open

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) has been used to quantify SO2 emissions from passively degassing volcanoes. This dissertation explores ASTER’s capability to detect SO2 with satellite validation, enhancement techniques and extensive processing of images at a variety of volcanoes. ASTER is compared to the Mini UV Spectrometer (MUSe), a ground based instrument, to determine if reasonable SO2 fluxes can be quantified from a plume emitted from Lascar, Chile. The two sensors were in good agreement with ASTER proving to be a reliable detector of SO2. ASTER illustrated the advantages of imaging a …

Go to article

Sampling Bias In Evaluating The Probability Of Seismically Induced Soil Liquefaction With Spt & Cpt Case Histories, Abhishek Jain Jan 2012

Sampling Bias In Evaluating The Probability Of Seismically Induced Soil Liquefaction With Spt & Cpt Case Histories, Abhishek Jain

Dissertations, Master's Theses and Master's Reports - Open

Several deterministic and probabilistic methods are used to evaluate the probability of seismically induced liquefaction of a soil. The probabilistic models usually possess some uncertainty in that model and uncertainties in the parameters used to develop that model. These model uncertainties vary from one statistical model to another. Most of the model uncertainties are epistemic, and can be addressed through appropriate knowledge of the statistical model. One such epistemic model uncertainty in evaluating liquefaction potential using a probabilistic model such as logistic regression is sampling bias. Sampling bias is the difference between the class distribution in the sample used for …

Go to article

Using Auto- And Cross-Correlations From Seismic Noise To Monitor Velocity Changes At Villarrica Volcano, Chile, Kathleen F. Mckee Jan 2012

Using Auto- And Cross-Correlations From Seismic Noise To Monitor Velocity Changes At Villarrica Volcano, Chile, Kathleen F. Mckee

Dissertations, Master's Theses and Master's Reports - Open

We used the Green's functions from auto-correlations and cross-correlations of seismic ambient noise to monitor temporal velocity changes in the subsurface at Villarrica volcano in the Southern Andes of Chile. Campaigns were conducted from March to October 2010 and February to April 2011 with 8 broadband and 6 short-period stations, respectively. We prepared the data by removing the instrument response, normalizing with a root-mean-square method, whitening the spectra, and filtering from 1 to 10 Hz. This frequency band was chosen based on the relatively high background noise level in that range. Hour-long auto- and cross-correlations were computed and the Green's …

Go to article

Effect Of Tray Type And Tray Covering On Wicking Speed, Germination, And Spiral Rooting Of Tobacco, William A. Bailey, Bill Pitt Jan 2012

Effect Of Tray Type And Tray Covering On Wicking Speed, Germination, And Spiral Rooting Of Tobacco, William A. Bailey, Bill Pitt

Plant and Soil Sciences Research Report

Poor tray wicking and spiral rooting continue to be recurring concerns in tobacco float systems. Poor wicking of trays can usually be attributed to old media or media that was improperly stored for extended periods of time. Tray design may also influence speed of wicking. The clay-based pelleting materials used to coat tobacco seeds are thought to cause damage to the emerging root radical under certain conditions, leading to an increased incidence of spiral root. Practices that change the microenvironment at the top of the cell area surrounding the seed may reduce spiral rooting by altering the breakdown of the …

Go to article

First Prev Next Last