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Articles 901 - 930 of 965
Full-Text Articles in Earth Sciences
Book Review: Water In Karst: Management, Vulnerability, And Restoration, Arthur N. Palmer
Book Review: Water In Karst: Management, Vulnerability, And Restoration, Arthur N. Palmer
International Journal of Speleology
Neven Kresic.
Water in Karst: Management, Vulnerability, and Restoration
New York, McGraw-Hill, 2013. ISBN 978-0-07-175333.3, 19×24 cm, 736 p. + 14 p. of color plates, hardbound,
US $125 (also available as e-book)
A Bank Erosion Hazard Index (Behi) Study Of Dry Run Creek, Cedar Falls, Iowa, Cara Wright
A Bank Erosion Hazard Index (Behi) Study Of Dry Run Creek, Cedar Falls, Iowa, Cara Wright
Honors Program Theses
Dry Run Creek is a watershed located in Cedar Falls; Iowa and it is on a list of the state's impaired waterways. One reason it may be impaired is that there is excessive erosion in the stream. This study assessed the Bank Erosion Hazard Index of portions of the creek to determine erosion hotspots. The majority of the banks in all the branches had a Low score, meaning that the BEHI was less than 11.9. The minimum BEHI score is O and the maximum score is 40. The lower the score, the better the condition of the bank. Portions of …
Book Review: Trevor Shaw And Alenka Čuk Slovene Caves & Karst, Pictured 1545-1914, Arrigo A. Cigna
Book Review: Trevor Shaw And Alenka Čuk Slovene Caves & Karst, Pictured 1545-1914, Arrigo A. Cigna
International Journal of Speleology
Trevor Shaw and Alenka Čuk.
Slovene Caves & Karst, pictured 1545-1914
Založba ZRC, Ljubljana, 2012.
ISBN 978-961-254-369-3, 230 p. 200x290, 258 b/w and colour illustrations, paper cover, € 25.00
Full Issue 42(2)
International Journal of Speleology
All articles in Volume 42 Issue 2. Does not include cover image.
Inter- And Intra-Annual Variability Of Vegetation In The Northern Hemisphere And Its Association With Precursory Meteorological Factors, Boksoon Myoung, Yong-Sang Choi, Seungbum Hong, Seon Ki Park
Inter- And Intra-Annual Variability Of Vegetation In The Northern Hemisphere And Its Association With Precursory Meteorological Factors, Boksoon Myoung, Yong-Sang Choi, Seungbum Hong, Seon Ki Park
Mathematics, Physics, and Computer Science Faculty Articles and Research
Determination of phenological variation is one of the most critical challenges in dynamic vegetation modeling, given the lack of a strong theoretical framework. Previous studies generally focused on the timing of a phenological event (e.g., bud-burst or onset of growing season) and its atmospheric prompts, but not on the interactive variations across phenological stages. This study, therefore, investigated the inter- and intra-annual variability existing in all the phenological stages and the relations of the variability with four meteorological variables (surface temperature (Ts), shortwave radiation (SW ), vapor pressure deficit (VPD), and precipitation (PRCP)) using a 25-year (1982-2006) dataset of leaf …
Multi Geophysical Parameters For Earthquake Forecasting, Ramesh P. Singh
Multi Geophysical Parameters For Earthquake Forecasting, Ramesh P. Singh
Mathematics, Physics, and Computer Science Faculty Articles and Research
This article focuses on the importance of keeping the public aware of earthquake forecasting. This article also encourages proper seismic codes to design buildings in the seismic-prone regions because such practice can save lives and property associated with an earthquake.
Hydraulic Fracturing Design For Horizontal Wells In The Bakken Formation, Williston Basin, Hadi Jabbari
Hydraulic Fracturing Design For Horizontal Wells In The Bakken Formation, Williston Basin, Hadi Jabbari
Theses and Dissertations
Unconventional hydrocarbon reservoirs have proved to be challenging in terms of reservoir characterization, predicting production potential, estimating ultimate recovery, and optimizing hydraulic fracture stimulations. The methods by which these resources are extracted use progressive, or unconventional, technologies. Today, through the use of hydraulic fracturing and horizontal drilling, extraordinary amounts of oil and natural gas from deep shale formations across the United States and around the world are being safely produced.
Performing a hydraulic fracture design requires modeling of fracture propagation and tracking the fluid front in the created fracture. In this dissertation, the roles of all effective parameters and properties …
Geophysical Investigation And Assessment Of The Rye Patch Known Geothermal Resource Area, Rye Patch, Nevada, Mark Richmond Mcdonald
Geophysical Investigation And Assessment Of The Rye Patch Known Geothermal Resource Area, Rye Patch, Nevada, Mark Richmond Mcdonald
Theses and Dissertations
A gravity and ground-based magnetic survey was conducted at the Rye Patch Known Geothermal Resource Area located at Rye Patch, Nevada. The purpose of the study was to attempt to further delineate the geothermal reservoir and/or to identify potential drilling targets. The survey consisted of collecting data at 264 new stations to augment data from 203 stations collected in 2008. Information from previous seismic, aeromagnetic and geochemical investigations was also examined and incorporated. Filtering methods including removal of a polynomial trend surface and wavelength filtering were utilized on the gravity data to remove the strong regional overprint caused by the …
Correcting Heat Flow Data In The United States To Account For Climate Change, Godswill Njoku
Correcting Heat Flow Data In The United States To Account For Climate Change, Godswill Njoku
Theses and Dissertations
Heat flow measurements may require correction for both recent warming and post-glacial warming signals. Warming during the last century can be detected in borehole temperature profiles. Both climate warming signals during the past century and post-glacial warming signals during the past 10 millennia are greatest near the surface and diminish with depth.
Both atmospheric data and borehole temperature data show that recent warming varies systematically with latitude along a north-south transect in the United States. The systematic increase with latitude from +0.7 oC at 41.6oN to +2.3 oC at 49oN during the last century is consistent with the prediction that …
Geomechanics And Elastic Anisotropy Of The Bakken Formation, Williston Basin, Mehdi Ostadhassan
Geomechanics And Elastic Anisotropy Of The Bakken Formation, Williston Basin, Mehdi Ostadhassan
Theses and Dissertations
Many of the earth’s rocks exhibit anisotropic characteristics. Anisotropy is particularly common in many sedimentary rocks, such as shales. Anisotropy is defined as the spatial alignment of mineral grains, layers, fractures and stresses which causes elastic wave velocity and other elastic properties to vary with direction. There are two types of anisotropy: intrinsic and stress-induced. Intrinsic anisotropy is caused by beddings, microstructures or aligned fractures formed during deposition. Stress-induced anisotropy is caused by strain associated with external stresses. Intrinsic anisotropy originates in the absence of external stresses, while stress-induced anisotropy results from tectonic and overburden stresses. The style of earth …
Lithological And Sequence Stratigraphic Examination Of The Madison Group Marker Beds, Eastern Williston Basin Margin, North Dakota, Troy Jd. Skitt
Lithological And Sequence Stratigraphic Examination Of The Madison Group Marker Beds, Eastern Williston Basin Margin, North Dakota, Troy Jd. Skitt
Theses and Dissertations
The Frobisher-Alida interval consists of eight log-defined subintervals or “beds” within the Mississippian upper Mission Canyon and lower Charles Formations of the Madison Group in the Williston Basin. The subintervals are composed of predominantly evaporite and carbonate lithologies, and include in descending order: 1) Midale, 2) Rival, 3) Bluell, 4) Sherwood, 5) Mohall, 6) Glenburn, 7) Wayne, and 8) Landa. The top of the lower six subintervals are separated by thin but areal extensive log-defined markers of contrasting lithologies and include in descending order: 1) State A, 2) Sherwood Argillaceous Marker (S.A.M.), 3) K-1, 4) K-2, 5) K-3, and 6) …
Early Eocene To Middle Miocene Cooling And Aridification Of East Antarctica, Sandra Passchier, Steven M. Bohaty, Francisco J. Jiménez‐Espejo, Jörg Pross, Ursu Röhl, Tina Van De Flierdt, Carlota Escutia, Henk Brinkhuis
Early Eocene To Middle Miocene Cooling And Aridification Of East Antarctica, Sandra Passchier, Steven M. Bohaty, Francisco J. Jiménez‐Espejo, Jörg Pross, Ursu Röhl, Tina Van De Flierdt, Carlota Escutia, Henk Brinkhuis
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
[1] Few high‐latitude terrestrial records document the timing and nature of the Cenozoic “Greenhouse” to “Icehouse” transition. Here we exploit the bulk geochemistry of marine siliciclastic sediments from drill cores on Antarctica's continental margin to extract a unique semiquantitative temperature and precipitation record for Eocene to mid‐Miocene (~54–13 Ma). Alkaline elements are strongly enriched in the detrital mineral fraction in fine‐grained siliciclastic marine sediments and only occur as trace metals in the biogenic fraction. Hence, terrestrial climofunctions similar to the chemical index of alteration (CIA) can be applied to the alkaline major element geochemistry of marine sediments on continental margins …
Visualizing And Understanding Tectonism And Volcanism On Earth And Other Terrestrial Bodies, Mladen M. Dordevic
Visualizing And Understanding Tectonism And Volcanism On Earth And Other Terrestrial Bodies, Mladen M. Dordevic
Physics Theses & Dissertations
This dissertation presents new methods of visualizing, teaching, assessing, modeling, and understanding tectonics on Earth and other celestial bodies. Tectonics is the study of planetary lithospheres and includes impact, plate, plume, cryo- and gravitational mechanisms. This dissertation is concerned with plate tectonics and plate/mantle plume interactions. Plate tectonics describes the mainly horizontal motion of lithospheric plates over the asthenosphere. Lithosphere is created at ridges and consumed at subduction zones. In addition to the plate tectonic system, mantle plumes also contribute to mass motions in the subsurface Earth. Both plate tectonics and plume upwelling processes help shape the present form of …
Balanced Cross Section Of The Northeast Of Adiyaman, Turkey, Mustafa Tuncer
Balanced Cross Section Of The Northeast Of Adiyaman, Turkey, Mustafa Tuncer
Masters Theses
"Deformation during closure of an ocean basin and continent-continent collision in southeast Anatolia Turkey during the Late Cretaceous to Middle Miocene was investigated by construction of a geologic map, structural cross-section and retrodeformed palinspastically restored cross-section. The area of study is a N-S transect across the Bitlis Suture Zone of Northeast of Adiyaman. The study area is situated in the southeast Anatolian orogenic belt which includes, from south to north, the Arabian platform, the zone of Imbrication, and the zone of Nappes. A geologic map of this region was prepared in order to construct balanced and restored cross sections from …
Watershed-Scale Hybrid Stochastic-Deterministic Modeling Framework And Diffused Sources Superpositioning, Ruby Juvah Damalie
Watershed-Scale Hybrid Stochastic-Deterministic Modeling Framework And Diffused Sources Superpositioning, Ruby Juvah Damalie
Civil & Environmental Engineering Theses & Dissertations
Predicting hydrologic system behavior is imperative to planning and management of water resources. The study developed an integrated hybrid stochastic and deterministic framework to improve prediction accuracy for overland flow and diffused sources in a watershed. The methodology includes sampling input parameters at system level and contribution of nonpoint source from hydrologically disconnected areas (heretofore referred to as system-level approach and superpositioning respectively). System-level approach includes the integration of a topography-based sampling grid generalized linear model developed by the study and Monte Carlo methods. The superpositioning method adopts in-stream water quality equation for overland flow pollution estimation.
The system-level approach …
The Geologic Records Of Dust In The Quaternary, Daniel R. Muhs
The Geologic Records Of Dust In The Quaternary, Daniel R. Muhs
United States Geological Survey: Staff Publications
Study of geologic records of dust composition, sources and deposition rates is important for understanding the role of dust in the overall planetary radiation balance, fertilization of organisms in the world’s oceans, nutrient additions to the terrestrial biosphere and soils, and for paleoclimatic reconstructions. Both glacial and non-glacial processes produce fine-grained particles that can be transported by the wind. Geologic records of dust flux occur in a number of depositional archives for sediments: (1) loess deposits; (2) lake sediments; (3) soils; (4) deep-ocean basins; and (5) ice sheets and smaller glaciers. These archives have several characteristics that make them highly …
Loess And Its Geomorphic, Stratigraphic, And Paleoclimatic Significance In The Quaternary, Daniel R. Muhs
Loess And Its Geomorphic, Stratigraphic, And Paleoclimatic Significance In The Quaternary, Daniel R. Muhs
United States Geological Survey: Staff Publications
Loess is aeolian silt visible in the field as a sedimentary body. It covers a significant portion of the land surface of the Earth. Loess thickness, particle size, and carbonate content decrease downwind from sources, useful trends for paleowinds. Many loess sections consist of relatively thick deposits of mostly unaltered sediment with intercalated paleosols. Paleosols represent periods of landscape stability when loess deposition slowed significantly. Loess in most regions was deposited during glacial periods and paleosols formed during interglacial periods. Loess has the potential to record the timing and environment of glacial–interglacial cycles of the Quaternary on many continents.
Reproductive Health Of Yellow Perch Perca Flavescens In Selected Tributaries Of The Chesapeake Bay, Vicki S. Blazer, Alfred E. Pinkney, Jill A. Jenkins, Luke R. Iwanowicz, Steven Minkkinen, Rassa O. Draugelis-Dale, James H. Uphoff
Reproductive Health Of Yellow Perch Perca Flavescens In Selected Tributaries Of The Chesapeake Bay, Vicki S. Blazer, Alfred E. Pinkney, Jill A. Jenkins, Luke R. Iwanowicz, Steven Minkkinen, Rassa O. Draugelis-Dale, James H. Uphoff
United States Geological Survey: Staff Publications
Reduced recruitment of yellow perch has been noted for a number of years in certain urbanized watersheds (South and Severn Rivers) of the Chesapeake Bay. Other rapidly developing watersheds such as Mattawoman Creek are more recently showing evidence of reduced recruitment of anadromous fishes. In this study, we used a battery of biomarkers to better document the reproductive health of adult yellow perch collected during spring spawning in 2007–2009. Perch were collected in the South and Severn Rivers, Mattawoman Creek and the less developed Choptank and Allen's Fresh watersheds for comparison. Gonadosomatic indices, plasma reproductive hormone concentrations, plasma vitellogenin concentrations …
Human-Caused Mortality Influences Spatial Population Dynamics: Pumas In Landscapes With Varying Mortality Risks, Jesse R. Newby, L. Scott Mills, Toni K. Ruth, Daniel H. Pletscher, Michael S. Mitchell, Howard B. Quigley, Kerry M. Murphy, Rich Desimone
Human-Caused Mortality Influences Spatial Population Dynamics: Pumas In Landscapes With Varying Mortality Risks, Jesse R. Newby, L. Scott Mills, Toni K. Ruth, Daniel H. Pletscher, Michael S. Mitchell, Howard B. Quigley, Kerry M. Murphy, Rich Desimone
United States Geological Survey: Staff Publications
An understanding of how stressors affect dispersal attributes and the contribution of local populations to multi-population dynamics are of immediate value to basic and applied ecology. Puma (Puma concolor) populations are expected to be influenced by inter-population movements and susceptible to human induced source–sink dynamics. Using long-term datasets we quantified the contribution of two puma populations to operationally define them as sources or sinks. The puma population in the Northern Greater Yellowstone Ecosystem (NGYE) was largely insulated from human-induced mortality by Yellowstone National Park. Pumas in the western Montana Garnet Mountain system were exposed to greater human-induced mortality, …
Performance Of Human Fecal Anaerobe-Associated Pcr-Based Assays In A Multi-Laboratory Method Evaluation Study, Blythe A. Layton, Yiping Cao, Darcy L. Ebentier, Kaitlyn Hanley, Elisenda Balleste, Joao Brandao, Muruleedhara Byappanahalli, Reagan Converse, Andreas H. Farnleitner, Jennifer Gentry-Shields, Maribeth L. Gidley, Michele Gourmelon, Chang Soo Lee, Jiyoung Lee, Solen Lozach, Tania Madi, Wim G. Meijer, Rachel Noble, Lindsay Peed, Georg H. Reischer, Raquel Rodrigues, Joan B. Rose, Alexander Schriewer, Chris Sinigalliano, Sangeetha Srinivasan, Jill Stewart, Laurie C. Van De Werfhorst, Dan Wang, Richard Whitman, Stefan Wuertz, Jenny Jay, Patricia A. Holden, Alexandria B. Boehm, Orin Shanks, John F. Griffith
Performance Of Human Fecal Anaerobe-Associated Pcr-Based Assays In A Multi-Laboratory Method Evaluation Study, Blythe A. Layton, Yiping Cao, Darcy L. Ebentier, Kaitlyn Hanley, Elisenda Balleste, Joao Brandao, Muruleedhara Byappanahalli, Reagan Converse, Andreas H. Farnleitner, Jennifer Gentry-Shields, Maribeth L. Gidley, Michele Gourmelon, Chang Soo Lee, Jiyoung Lee, Solen Lozach, Tania Madi, Wim G. Meijer, Rachel Noble, Lindsay Peed, Georg H. Reischer, Raquel Rodrigues, Joan B. Rose, Alexander Schriewer, Chris Sinigalliano, Sangeetha Srinivasan, Jill Stewart, Laurie C. Van De Werfhorst, Dan Wang, Richard Whitman, Stefan Wuertz, Jenny Jay, Patricia A. Holden, Alexandria B. Boehm, Orin Shanks, John F. Griffith
United States Geological Survey: Staff Publications
A number of PCR-based methods for detecting human fecal material in environmental waters have been developed over the past decade, but these methods have rarely received independent comparative testing in large multi-laboratory studies. Here, we evaluated ten of these methods (BacH, BacHum-UCD, Bacteroides thetaiotaomicron (BtH), BsteriF1, gyrB, HF183 endpoint, HF183 SYBR, HF183 Taqman®, HumM2, and Methanobrevibacter smithii nifH (Mnif)) using 64 blind samples prepared in one laboratory. The blind samples contained either one or two fecal sources from human, wastewater or non-human sources. The assay results were assessed for presence/absence of the human markers and also quantitatively while …
An Algorithmic And Information-Theoretic Approach To Multimetric Index Construction, Donald R. Schoolmaster Jr., James B. Grace, E. William Schweiger, Glenn R. Guntenspergen, Brian R. Mitchell, Kathryn M. Miller, Amanda M. Little
An Algorithmic And Information-Theoretic Approach To Multimetric Index Construction, Donald R. Schoolmaster Jr., James B. Grace, E. William Schweiger, Glenn R. Guntenspergen, Brian R. Mitchell, Kathryn M. Miller, Amanda M. Little
United States Geological Survey: Staff Publications
The use of multimetric indices (MMIs), such as the widely used index of biological integrity (IBI), to measure, track, summarize and infer the overall impact of human disturbance on biological communities has been steadily growing in recent years. Initially, MMIs were developed for aquatic communities using preselected biological metrics as indicators of system integrity. As interest in these bioassessment tools has grown, so have the types of biological systems to which they are applied. For many ecosystem types the appropriate biological metrics to use as measures of biological integrity are not known a priori. As a result, a variety of …
Controls On Recent Alaskan Lake Changes Identified From Water Isotopes And Remote Sensing, Lesleigh Anderson, Jennifer Rover, Nikki Gaulager, Jean Birks
Controls On Recent Alaskan Lake Changes Identified From Water Isotopes And Remote Sensing, Lesleigh Anderson, Jennifer Rover, Nikki Gaulager, Jean Birks
United States Geological Survey: Staff Publications
High-latitude lakes are important for terrestrial carbon dynamics and waterfowl habitat driving a need to better understand controls on lake area changes. To identify the existence and cause of recent lake area changes in the Yukon Flats, a region of discontinuous permafrost in north central Alaska, we evaluate remotely sensed imagery with lake water isotope compositions and hydroclimatic parameters. Isotope compositions indicate that mixtures of precipitation, river water, and groundwater source ~95% of the studied lakes. The remaining minority are more dominantly sourced by snowmelt and/or permafrost thaw. Isotope-based water balance estimates indicate 58% of lakes lose more than half …
Extending Airborne Electromagnetic Surveys For Regional Active Layer And Permafrost Mapping With Remote Sensing And Ancillary Data, Yukon Flats Ecoregion, Central Alaska, Neal J. Pastick, M. Torre Jorgenson, Bruce K. Wylie, Burke J. Minsley, Lei Ji, Michelle A. Walvoord, Bruce D. Smith, Jared D. Abraham, Joshua R. Rose
Extending Airborne Electromagnetic Surveys For Regional Active Layer And Permafrost Mapping With Remote Sensing And Ancillary Data, Yukon Flats Ecoregion, Central Alaska, Neal J. Pastick, M. Torre Jorgenson, Bruce K. Wylie, Burke J. Minsley, Lei Ji, Michelle A. Walvoord, Bruce D. Smith, Jared D. Abraham, Joshua R. Rose
United States Geological Survey: Staff Publications
Machine-learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at-sensor reflectance, thermal, TM-derived spectral indices, digital elevation models and other relevant spatial data to estimate near-surface (0–2.6-m depth) resistivity at 30-m resolution. A piecewise regression model (r = 0.82) and a presence/absence decision tree classification (accuracy of 87%) were used to estimate active-layer thickness (ALT) (< 101 cm) and the probability of near-surface (up to 123-cm depth) permafrost occurrence from field data, modelled near-surface (0–2.6m) resistivity, and other relevant remote sensing and map data. At site scale, the predicted ALTs were similar to those previously observed for different vegetation types. At the landscape scale, the predicted ALTs tended to be thinner on higher-elevation loess deposits than on low-lying alluvial and sand sheet deposits of the Yukon Flats. The ALT and permafrost maps provide a baseline for future permafrost monitoring, serve as inputs for modelling hydrological and carbon cycles at local to regional scales, and offer insight into the ALT response to fire and thaw processes. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
A Review Of Environmental Impacts Of Salts From Produced Waters On Aquatic Resources, Aida M. Farag, David D. Harper
A Review Of Environmental Impacts Of Salts From Produced Waters On Aquatic Resources, Aida M. Farag, David D. Harper
United States Geological Survey: Staff Publications
Salts are frequently amajor constituent ofwastewaters produced during oil and gas production. These produced waters or brines must be treated and/or disposed and provide a daily challenge for operators and resourcemanagers. Some elements of salts are regulated with water quality criteria established for the protection of aquatic wildlife, e.g. chloride (Cl−), which has an acute standard of 860 mg/L and a chronic standard of 230 mg/L. However, data for establishing such standards has only recently been studied for other components of produced water, such as bicarbonate (HCO3 −), which has acute median lethal concentrations (LC50s) ranging from …
Ice-Age Megafauna In Arctic Alaska: Extinction, Invasion, Survival, Daniel H. Mann, Pamela Groves, Michael L. Kunz, Richard E. Reanier, Benjamin V. Gaglioti
Ice-Age Megafauna In Arctic Alaska: Extinction, Invasion, Survival, Daniel H. Mann, Pamela Groves, Michael L. Kunz, Richard E. Reanier, Benjamin V. Gaglioti
United States Geological Survey: Staff Publications
Radical restructuring of the terrestrial, large mammal fauna living in arctic Alaska occurred between 14,000 and 10,000 years ago at the end of the last ice age. Steppe bison, horse, and woolly mammoth became extinct, moose and humans invaded, while muskox and caribou persisted. The ice age mega fauna was more diverse in species and possibly contained 6x more individual animals than live in the region today. Mega faunal biomass during the last ice age may have been 30x greater than present. Horse was the dominant species in terms of number of individuals. Lions, short-faced bears, wolves, and possibly grizzly …
Origin Of The Sinai-Negev Erg, Egypt And Israel: Mineralogical And Geochemical Evidence For The Importance Of The Nile And Sea Level History, Daniel R. Muhs, Joel Roskin, Haim Tsoar, Gary Skipp, James Budahn, Amihai Sneh, Naomi Porat, Jean-Daniel Stanley, Itzhak Katra, Dan G. Blumberg
Origin Of The Sinai-Negev Erg, Egypt And Israel: Mineralogical And Geochemical Evidence For The Importance Of The Nile And Sea Level History, Daniel R. Muhs, Joel Roskin, Haim Tsoar, Gary Skipp, James Budahn, Amihai Sneh, Naomi Porat, Jean-Daniel Stanley, Itzhak Katra, Dan G. Blumberg
United States Geological Survey: Staff Publications
The Sinai-Negev erg occupies an area of 13,000 km2 in the deserts of Egypt and Israel. Aeolian sand of this erg has been proposed to be derived from the Nile Delta, but empirical data supporting this view are lacking. An alternative source sediment is sand from the large Wadi El Arish drainage system in central and northern Sinai. Mineralogy of the Negev and Sinai dunes shows that they are high in quartz, with much smaller amounts of K-feldspar and plagioclase. Both Nile Delta sands and Sinai wadi sands, upstream of the dunes, also have high amounts of quartz relative …
Chronology And Provenance Of Last-Glacial (Peoria) Loess In Western Iowa And Paleoclimatic Implications, Daniel R. Muhs, E. Arthur Bettis Iii, Helen M. Roberts, Stephen S. Harlan, James B. Paces, Richard L. Reynolds
Chronology And Provenance Of Last-Glacial (Peoria) Loess In Western Iowa And Paleoclimatic Implications, Daniel R. Muhs, E. Arthur Bettis Iii, Helen M. Roberts, Stephen S. Harlan, James B. Paces, Richard L. Reynolds
United States Geological Survey: Staff Publications
Geologic archives show that the Earth was dustier during the last glacial period. One model suggests that increased gustiness (stronger, more frequent winds) enhanced dustiness. We tested this at Loveland, Iowa, one of the thickest deposits of last-glacial-age (Peoria) loess in the world. Based on K/Rb and Ba/Rb, loess was derived not only from glaciogenic sources of the Missouri River, but also distal loess from non-glacial sources in Nebraska. Optically stimulated luminescence (OSL) ages provide the first detailed chronology of Peoria Loess at Loveland. Deposition began after ~27 ka and continued until ~17 ka. OSL ages also indicate that mass …
Radiocarbon Dating Late Quaternary Loess Deposits Using Small Terrestrial Gastropod Shells, Jeffrey S. Pigati, John Mcgeehin, Daniel R. Muhs, E. Arthur Bettis Iii
Radiocarbon Dating Late Quaternary Loess Deposits Using Small Terrestrial Gastropod Shells, Jeffrey S. Pigati, John Mcgeehin, Daniel R. Muhs, E. Arthur Bettis Iii
United States Geological Survey: Staff Publications
No abstract provided.
Toxic Exposure Of Songbirds To Lead In The Southeast Missouri Lead Mining District, W. Nelson Beyer, J. Christian Franson, John B. French, Thomas May, Barnett A. Rattner, Valerie I. Shearn-Bochsler, Sarah E. Warner, John Weber, David Mosby
Toxic Exposure Of Songbirds To Lead In The Southeast Missouri Lead Mining District, W. Nelson Beyer, J. Christian Franson, John B. French, Thomas May, Barnett A. Rattner, Valerie I. Shearn-Bochsler, Sarah E. Warner, John Weber, David Mosby
United States Geological Survey: Staff Publications
Mining and smelting in the Southeast Missouri Lead Mining District has caused widespread contamination of soils with lead (Pb) and other metals. Soils from three study sites sampled in the district contained from approximately 1,000–3,200 mg Pb/kg. Analyses of earthworms [33–4,600 mg Pb/kg dry weight (dw)] collected in the district showed likely high Pb exposure of songbirds preying on soil organisms. Mean tissue Pb concentrations in songbirds collected from the contaminated sites were greater (p < 0.05) than those in songbirds from reference sites by factors of 8 in blood, 13 in liver, and 23 in kidney. Ranges of Pb concentrations in livers (mg Pb/kg dw) were as follows: northern cardinal (Cardinalis cardinalis) = 0.11–3.0 (reference) and 1.3–30 (contaminated) and American robin (Turdus migratorius) = 0.43–8.5 (reference) and 7.6–72 (contaminated). Of 34 …