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Articles 2761 - 2790 of 4541

Full-Text Articles in Earth Sciences

Lake Sediments Record Large-Scale Shifts In Moisture Regimes Across The Northern Prairies Of North America During The Past Two Millennia, Kathleen R. Laird, Brian F. Cumming, Sybille Wunsam, James A. Rusak, Robert J. Oglesby, Sherilyn C. Fritz, Peter R. Leavitt Jan 2003

Lake Sediments Record Large-Scale Shifts In Moisture Regimes Across The Northern Prairies Of North America During The Past Two Millennia, Kathleen R. Laird, Brian F. Cumming, Sybille Wunsam, James A. Rusak, Robert J. Oglesby, Sherilyn C. Fritz, Peter R. Leavitt

Department of Earth and Atmospheric Sciences: Faculty Publications

Six high-resolution climatic reconstructions, based on diatom analyses from lake sediment cores from the northern prairies of North America, show that shifts in drought conditions on decadal through multicentennial scales have prevailed in this region for at least the last two millennia. The predominant broad-scale pattern seen at all sites is a major shift in moisture regimes from wet to dry, or vice versa (depending on location), that occurred after a period of relative stability. These large-scale shifts at the different sites exhibit spatial coherence at regional scales. The three Canadian sites record this abrupt shift between anno Domini 500 …

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Climate Effects On Corn Yield In Missour, Q. Steven Hu, Gregory Buyanovsky Jan 2003

Climate Effects On Corn Yield In Missour, Q. Steven Hu, Gregory Buyanovsky

Department of Earth and Atmospheric Sciences: Faculty Publications

Understanding climate effects on crop yield has been a continuous endeavor aiming at improving farming technology and management strategy, minimizing negative climate effects, and maximizing positive climate effects on yield. Many studies have examined climate effects on corn yield in different regions of the United States. However, most of those studies used yield and climate records that were shorter than 10 years and were for different years and localities. Although results of those studies showed various influences of climate on corn yield, they could be time specific and have been difficult to use for deriving a comprehensive understanding of climate …

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Furnas County Test Hole Logs, Frank A. Smith Jan 2003

Furnas County Test Hole Logs, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Weathering Of Sulfidic Shale And Copper Mine Waste: Secondary Minerals And Metal Cycling In Great Smoky Mountains National Park, Tennessee, And North Carolina, Usa, Jane M. Hammarstrom, Robert R. Seal Ii, Allen L. Meier, John C. Jackson Jan 2003

Weathering Of Sulfidic Shale And Copper Mine Waste: Secondary Minerals And Metal Cycling In Great Smoky Mountains National Park, Tennessee, And North Carolina, Usa, Jane M. Hammarstrom, Robert R. Seal Ii, Allen L. Meier, John C. Jackson

United States Geological Survey: Staff Publications

Metal cycling via physical and chemical weathering of discrete sources (copper mines) and regional (non-point) sources (sulfide-rich shale) is evaluated by examining the mineralogy and chemistry of weathering products in Great Smoky Mountains National Park, Tennessee, and North Carolina, USA. The elements in copper mine waste, secondary minerals, stream sediments, and waters that are most likely to have negative impacts on aquatic ecosystems are aluminum, copper, zinc, and arsenic because these elements locally exceed toxicity guidelines for surface waters or for stream sediments. Acid-mine drainage has not developed in streams draining inactive copper mines. Acid-rock drainage and chemical weathering processes …

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Field Trip Guide (For The Nebraska Well Drillers Association) Northeastern Nebraska Geology, S. Olafsen-Lackey, D. Eversoll Jan 2003

Field Trip Guide (For The Nebraska Well Drillers Association) Northeastern Nebraska Geology, S. Olafsen-Lackey, D. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Stream Bank Stability In Eastern Nebraska, Philip J. Soenksen, Mary J. Turner, Benjamin J. Dietsch, Andrew Simon Jan 2003

Stream Bank Stability In Eastern Nebraska, Philip J. Soenksen, Mary J. Turner, Benjamin J. Dietsch, Andrew Simon

United States Geological Survey: Publications

Dredged and straightened channels in eastern Nebraska have experienced degradation leading to channel widening by bank failure. Degradation has progressed headward and affected the drainage systems upstream from the modified reaches. This report describes a study that was undertaken to analyze bank stability at selected sites in eastern Nebraska and develop a simplified method for estimating the stability of banks at future study sites. Bank cross sections along straight reaches of channel and geotechnical data were collected at approximately 150 sites in 26 counties of eastern Nebraska. The sites were categorized into three groups based on mapped soil permeability. With …

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Streambed Adjustment And Channel Widening In Eastern Nebraska, David L. Rus, Benjamin J. Dietsch, Andrew Simon Jan 2003

Streambed Adjustment And Channel Widening In Eastern Nebraska, David L. Rus, Benjamin J. Dietsch, Andrew Simon

United States Geological Survey: Publications

In eastern Nebraska, stream straightening and dredging efforts since the 1890s have disturbed the natural equilibrium of stream channels and have led to streambed adjustment by degradation and subsequent channel widening. This report describes a study to evaluate the effect these disturbances have had on stream channels in eastern Nebraska.

Two sets of survey data were collected approximately 2 years apart during 1996–99 at 151 primary sites. Additionally, historical streambed-elevation data (dating back to the 1890s) were compiled from several sources for the primary sites and 45 supplemental sites, and relevant disturbances were identified for each of eight basin groupings. …

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Reconnaissance Of Acid Drainage Sources And Preliminary Evaluation Of Remedial Alternatives At The Copper Bluff Mine, Hoopa Valley Reservation, California, Charles N. Alpers, Michael P. Hunerlach, Scott N. Hamlin, Robert A. Zierenberg Jan 2003

Reconnaissance Of Acid Drainage Sources And Preliminary Evaluation Of Remedial Alternatives At The Copper Bluff Mine, Hoopa Valley Reservation, California, Charles N. Alpers, Michael P. Hunerlach, Scott N. Hamlin, Robert A. Zierenberg

United States Geological Survey: Publications

Acidic drainage from the inactive Copper Bluff mine cascades down a steep embankment into the Trinity River, on the Hoopa Valley Reservation in northern California. The Copper Bluff mine produced about 100,000 tons of sulfide-bearing copper-zinc-gold-silver ore during 1957–1962. This report summarizes the results of a water-resources investigation begun by the U.S. Geological Survey in 1994 with the overall objective of gathering sufficient geochemical, hydrologic, and geologic information so that a sound remediation strategy for the Copper Bluff mine could be selected and implemented by the Hoopa Valley Tribe. This study had the following specific objectives: (1) monitor the quality …

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Sediment-Water Interactions Affecting Dissolved-Mercury Distributions In Camp Far West Reservoir, California, James S. Kuwabara, Charles N. Alpers, Mark Marvin-Dipasquale, Brent R. Topping, James L. Carter, A. Robin Stewart, Steven V. Fend, Francis Parchaso, Gerald E. Moon, David P. Krabbenhoft Jan 2003

Sediment-Water Interactions Affecting Dissolved-Mercury Distributions In Camp Far West Reservoir, California, James S. Kuwabara, Charles N. Alpers, Mark Marvin-Dipasquale, Brent R. Topping, James L. Carter, A. Robin Stewart, Steven V. Fend, Francis Parchaso, Gerald E. Moon, David P. Krabbenhoft

United States Geological Survey: Publications

Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest …

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Groundwater Flow Andwater Quality – A Flowpath Study In The Seminolewell Field, Cedar Rapids, Iowa, Douglas J. Schnoebelen, Michael J. Turco, John D. North Jan 2003

Groundwater Flow Andwater Quality – A Flowpath Study In The Seminolewell Field, Cedar Rapids, Iowa, Douglas J. Schnoebelen, Michael J. Turco, John D. North

United States Geological Survey: Staff Publications

In Iowa, alluvial aquifers near major rivers are a source of water for many communities. The City of Cedar Rapids withdraws water from wells completed in the Cedar River alluvium, a shallow alluvial aquifer adjacent to the Cedar River. The City of Cedar Rapids is located within Linn County in east-central Iowa, and water for the City is supplied by four well fields (East, Northwest, Seminole, and West well fields) along the Cedar River. The City has a population of about 121,000, and several large industries are major water users. Currently, per capita water usage in the City is nearly …

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Annual Inflow Of Water To Nebraska And Annual Outflow Of Water From Nebraska, 1950 - 2003, S. E. Summerside, W. Myers, S. Olafsen-Lackey Jan 2003

Annual Inflow Of Water To Nebraska And Annual Outflow Of Water From Nebraska, 1950 - 2003, S. E. Summerside, W. Myers, S. Olafsen-Lackey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Lancaster County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 2003

Lancaster County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Democratizing Science, Management, And Public Policy In The Missouri River Ecosystem: A Pilot Study Of Agricultural Producers' Amenability To Adaptive And Collaborative Management, Meghan Sittler Jan 2003

Democratizing Science, Management, And Public Policy In The Missouri River Ecosystem: A Pilot Study Of Agricultural Producers' Amenability To Adaptive And Collaborative Management, Meghan Sittler

School of Natural Resources: Dissertations, Theses, and Student Research

Agricultural stakeholder involvement is central to the National Academy of Sciences' (NAS) National Research Council (NRC)(2002) recommendation for development and implementation of adaptive, ecosystem management principles, as well as the definition of a new management regime for the Missouri River. This document represents a pilot study of fifteen agricultural producers in three counties, Atchison County, Missouri, Fremont County, Iowa, and Otoe County, Nebraska, who were contacted via telephone and completed structured interviews. The interview questions centered upon the producers' relationship to the river, perceptions of the current management of the river, and willingness to support and participate in a proposed …

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Sulfate Oxygen-17 Anomaly In An Oligocene Ash Bed In Mid-North America: Was It The Dry Fogs?, Huiming Bao, Mark H. Thiemens, David B. Loope, Xun-Lai Yuan Jan 2003

Sulfate Oxygen-17 Anomaly In An Oligocene Ash Bed In Mid-North America: Was It The Dry Fogs?, Huiming Bao, Mark H. Thiemens, David B. Loope, Xun-Lai Yuan

Department of Earth and Atmospheric Sciences: Faculty Publications

The oxygen and sulfur isotope compositions of sulfate, particularly the oxygen-17 anomaly, provide clues to the origin of sulfate. We report a variable oxygen-17 anomaly for water- and acid-leached sulfate from an Oligocene volcanic ash bed in the northern High Plains, U.S.A. We find no sulfate O-17 anomaly, however, in freshly collected ashes from recent eruptions around the world. The Oligocene paleoclimatic and sedimentary evidence argues against a hyperarid condition in the High Plains, thus a long-term background atmospheric sulfate accumulation is less likely the origin. Combining sulfur isotope data, we suggest that the anomalous sulfate was associated with volcanic …

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Pliocene Summer Sea Surface Temperature Reconstruction Using Silicoflagellates From Southern Ocean Odp Site 1165, Jason M. Whitehead, Steven M. Bohaty Jan 2003

Pliocene Summer Sea Surface Temperature Reconstruction Using Silicoflagellates From Southern Ocean Odp Site 1165, Jason M. Whitehead, Steven M. Bohaty

Department of Earth and Atmospheric Sciences: Faculty Publications

In the modern marine environment the silicoflagellate genus Dictyocha is rare, or absent, south of the Antarctic polar front (APF); the genus Distephanus, in contrast, is dominant. In sediments recovered from ODP Site 1165, 1600 km south of the front, however, three intervals where Dictyocha is abundant are interpreted to represent Pliocene warm events. Comparison of our data with Ciesielski and Weaver’s [1974] modern core top silicoflagellate relationship with sea surface temperature (SST) indicates that at Site 1165 mean annual SST was approximately 5C at 3.7 Ma (event I), and approximately 4C at 4.3–4.4 Ma (event II) and 4.55–4.8 …

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2003 Changes To Water Transfer Law In Nebraska- Addendum, J. Michael Jess Jan 2003

2003 Changes To Water Transfer Law In Nebraska- Addendum, J. Michael Jess

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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A Reconnaissance Scale Assessment Of Confining Conditions Within The Ground-Water System Of The Principal Aquifer In The Upper Big Blue Nrd, S. E. Summerside, R. Vasek, D. C. Gosselin, J. M. Jess Jan 2003

A Reconnaissance Scale Assessment Of Confining Conditions Within The Ground-Water System Of The Principal Aquifer In The Upper Big Blue Nrd, S. E. Summerside, R. Vasek, D. C. Gosselin, J. M. Jess

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Estimation Of Hydraulic Conductivity From Borehole Flowmeter Tests Considering Head Losses, Vitaly A. Zlotnik, Brian R. Zurbuchen Jan 2003

Estimation Of Hydraulic Conductivity From Borehole Flowmeter Tests Considering Head Losses, Vitaly A. Zlotnik, Brian R. Zurbuchen

Department of Earth and Atmospheric Sciences: Faculty Publications

Recent numerical studies have demonstrated that the conventional interpretation of the borehole flowmeter test (BFT) may lead to considerable errors in estimates of the horizontal hydraulic conductivity (Kr) due to neglect of head loss across the electromagnetic borehole flowmeter (EBF). Even in uniform aquifers, the conventional interpretation underestimates Kr at the base and overestimates Kr at the top of the aquifer. In this paper, we derive exact analytical solutions for hydraulic head and streamlines induced by the BFT in a confined homogeneous aquifer. The solutions explicitly consider head loss across the EBF. The derived analytical solutions …

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Butler County Test Hole Logs, Scott E. Summerside, Raymond R. Burchett Jan 2003

Butler County Test Hole Logs, Scott E. Summerside, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Seward County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 2003

Seward County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Nebraska Birds In Recorded History, Fritz L. Knopf Jan 2003

Nebraska Birds In Recorded History, Fritz L. Knopf

United States Geological Survey: Staff Publications

The critical image of historical perspective is lacking in much of conservation biology's dialogue on protecting biotic diversity. Some biologists offer that the vision for bird conservation on the Central Grasslands of North America is to secure at least fragments of the avian assemblage that coexisted with Native Americans when Europeans first arrived. Nowhere, however, has anyone really tried to re-create such a historical image in any biological arena, until now.

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Eolian Sand Transport Pathways In The Southwestern United States: Importance Of The Colorado River And Local Sources, Daniel R. Muhs, Richard L. Reynolds, Josh Been, Gary Skipp Jan 2003

Eolian Sand Transport Pathways In The Southwestern United States: Importance Of The Colorado River And Local Sources, Daniel R. Muhs, Richard L. Reynolds, Josh Been, Gary Skipp

United States Geological Survey: Staff Publications

Geomorphologists have long recognized that eolian sand transport pathways extend over long distances in desert regions. Along such pathways, sediment transport by wind can surmount topographic obstacles and cross major drainages. Recent studies have suggested that three distinct eolian sand transport pathways exist (or once existed) in the Mojave and Sonoran Desert regions of the southwestern United States. One hypothesized pathway is eolian sand transport from the eastern Mojave Desert of California into western Arizona, near Parker, and would require sand movement across what must have been at least a seasonally dry Colorado River valley. We tested this hypothesis by …

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Quaternary Sedimentation And Subsidence History Of Lake Baikal, Siberia, Based On Seismic Stratigraphy And Coring, S. M. Colman, E. B. Karabanov, C. H. Nelson Iii Jan 2003

Quaternary Sedimentation And Subsidence History Of Lake Baikal, Siberia, Based On Seismic Stratigraphy And Coring, S. M. Colman, E. B. Karabanov, C. H. Nelson Iii

United States Geological Survey: Staff Publications

The long, continuous, high-latitude, stratigraphic record of Lake Baikal was deposited in three broad sedimentary environments, defined by high-resolution seismic-reflection and coring methods: (1) turbidite depositional systems, by far the most widespread, characterizing most of the margins and floors of the main basins of the lake, (2) large deltas of major drainages, and (3) tectonically or topographically isolated ridges and banks. Holocene sedimentation rates based on radiocarbon ages vary by more than an order of magnitude among these environments, from less than about 0.03 mm/yr on ridges and banks to more than about 0.3 mm/yr on basin floors. Extrapolating these …

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Birth Of The Modern Chesapeake Bay Estuary Between 7.4 And 8.2 Ka And Implications For Global Sea-Level Rise, John F. Bratton, Steven M. Colman, E. Robert Thieler, Robert R. Seal Ii Jan 2003

Birth Of The Modern Chesapeake Bay Estuary Between 7.4 And 8.2 Ka And Implications For Global Sea-Level Rise, John F. Bratton, Steven M. Colman, E. Robert Thieler, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum – meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystems which ring the world’s oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay which span the transition from fresh to brackish water conditions in the bay in the mid- Holocene. These data constrain sea-level change and resulting environmental change in the bay. They indicate …

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Acquisition And Evaluation Of Thermodynamic Data For Morenosite-Retgersite Equilibria At 0.1 Mpa, I-Ming Chou, Robert R. Seal Ii Jan 2003

Acquisition And Evaluation Of Thermodynamic Data For Morenosite-Retgersite Equilibria At 0.1 Mpa, I-Ming Chou, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Metal-sulfate salts in mine drainage environments commonly occur as solid solutions containing Fe, Cu, Mg, Zn, Al, Mn, Ni, Co, Cd, and other elements. Thermodynamic data for some of the endmember salts containing Fe, Cu, Zn, and Mg have been collected and evaluated previously, and the present study extends to the system containing Ni. Morenosite (NiSO4•7H2O)-retgersite (NiSO4•6H2O) equilibria were determined along five humidity buffer curves at 0.1 MPa and between 5 and 22 °C. Reversals along these humidity-buffer curves yield ln K = 17.58–6303.35/T, where K is the equilibrium constant, …

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Effects Of Crustal Stresses On Fluid Transport In Fractured Rock: Case Studies From Northeastern And Southwestern Usa, Roger H. Morin, William Z. Savage Jan 2003

Effects Of Crustal Stresses On Fluid Transport In Fractured Rock: Case Studies From Northeastern And Southwestern Usa, Roger H. Morin, William Z. Savage

United States Geological Survey: Staff Publications

The link between stress and hydrologic properties was examined at two sites that are distinguished by different rock types and different stress states. This investigation is based upon the analysis and interpretation of geophysical logs obtained in water wells at the two locations. At the northeast site (Newark Basin), the hydrologic characteristics of sedimentary rocks are dependent upon the relationship to the current regional stress field of two primary types of orthogonal features that serve as preferential pathways for fluid flow. Subhorizontal bedding-plane partings are highly transmissive near the surface and delineate transversely isotropic fluid flow at shallow depths. With …

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Influence Of The Pacific Decadal Oscillation On The Climate Of The Sierra Nevada, California And Nevada, Larry Benson, Braddock Linsley, Joe Smoot, Scott Mensing, Steve Lund, Scott Stine, Andre Sarna-Wojcicki Jan 2003

Influence Of The Pacific Decadal Oscillation On The Climate Of The Sierra Nevada, California And Nevada, Larry Benson, Braddock Linsley, Joe Smoot, Scott Mensing, Steve Lund, Scott Stine, Andre Sarna-Wojcicki

United States Geological Survey: Staff Publications

Mono Lake sediments have recorded five major oscillations in the hydrologic balance between A.D. 1700 and 1941. These oscillations can be correlated with tree-ring-based oscillations in Sierra Nevada snowpack. Comparison of a tree-ring-based reconstruction of the Pacific Decadal Oscillation (PDO) index (D’Arrigo et al., 2001) with a coral-based reconstruction of Subtropical South Pacific sea-surface temperature (Linsley et al., 2000) indicates a high degree of correlation between the two records during the past 300 yr. This suggests that the PDO has been a pan-Pacific phenomena for at least the past few hundred years. Major oscillations in the hydrologic balance of the …

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Age Of The Mono Lake Excursion And Associated Tephra, Larry Benson, Joseph Liddicoat, Joseph Smoot, Andrei Sarna-Wojcicki, Robert M. Negrini, Steve Lund Jan 2003

Age Of The Mono Lake Excursion And Associated Tephra, Larry Benson, Joseph Liddicoat, Joseph Smoot, Andrei Sarna-Wojcicki, Robert M. Negrini, Steve Lund

United States Geological Survey: Staff Publications

The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash #15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,620 ± 300 14C yr BP (~32,400 GISP2 yr BP) …

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Aeolian Cliff-Top Deposits And Buried Soils In The White River Badlands, South Dakota, Usa, J. Elmo Rawling Iii, Glen G. Fredlund, Shannon Mahan Jan 2003

Aeolian Cliff-Top Deposits And Buried Soils In The White River Badlands, South Dakota, Usa, J. Elmo Rawling Iii, Glen G. Fredlund, Shannon Mahan

United States Geological Survey: Staff Publications

Aeolian deposits in the North American Great Plains are important sources of Holocene palaeoenvironmental records. Although there are extensive studies on loess and dune records in the region, little is known about records in aeolian cliff-top deposits. These are common on table (mesa) edges in the White River Badlands. These sediments typically have loam and sandy-loam textures with dominantly very fine sand, 0.5–1% organic carbon and 0.5–5% CaCO3. Some of these aeolian deposits are atypically coarse and contain granules and fine pebbles. Buried soils within these deposits are weakly developed with A-C and A-AC-C profiles. Beneath these are …

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Quaternary Loess-Paleosol Sequences As Examples Of Climate-Driven Sedimentary Extremes, Daniel R. Muhs, E. Arthur Bettis Iii Jan 2003

Quaternary Loess-Paleosol Sequences As Examples Of Climate-Driven Sedimentary Extremes, Daniel R. Muhs, E. Arthur Bettis Iii

United States Geological Survey: Staff Publications

Loess is a widespread, wind-transported, silt-dominated deposit that contains geologic archives of atmospheric circulation and paleoclimate on continents. Loess may cover as much as 10% of the Earth’s land surface. It is composed mainly of quartz, feldspars, and clay minerals, with varying amounts of carbonate minerals. The geochemistry of loess differs from region to region, depending on source materials, but all loess is very high in SiO2 with lesser amounts of other major elements. Trends in loess downwind from source areas include systematic decreases in thickness and amounts of sand and coarse silt, and increases in amounts of fine silt …

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