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Articles 3361 - 3390 of 4541

Full-Text Articles in Earth Sciences

Directory Of Nebraska Quarries, Pits, And Mines, R. R. Burchett Jan 1994

Directory Of Nebraska Quarries, Pits, And Mines, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Cleat-Filling Calcite In Illinois Basin Coals: Trace-Element Evidence For Meteoric Fluid Migration In A Coal Basin, Allan Kolker, Chen-Lin Chou Jan 1994

Cleat-Filling Calcite In Illinois Basin Coals: Trace-Element Evidence For Meteoric Fluid Migration In A Coal Basin, Allan Kolker, Chen-Lin Chou

Department of Earth and Atmospheric Sciences: Faculty Publications

The microdistribution of Mn (786 to 9480 ppm), Sr (<5 to 461 ppm), and Fe (52 to 16,700 ppm) was determined for cleat-filling calcites in the Herrin, Springfield, and Colchester Coals, using focussed synchrotron radiation. Compositional zonation in the calcites reflects a multistage history of precipitation from fluids with differing trace-element characteristics. In nearly all of the samples, a high Fe (≥~5000 ppm) calcite is the latest composition to form, replacing earlier stages with varying, but generally lower Fe contents. Partitioning data for Sr suggest that a typical calcite with 200 ppm Sr formed from a fluid with a Sr/Ca of about 0.005. This Sr/Ca is ~4 times lower than seawater, and ~12 times lower than the average for present day Illinois Basin saline formation waters. Formation of cleat-filling calcite is best explained by precipitation from fluids similar to present day dilute (shallow) formation waters having a meteoric source.

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A Field Trip To The Sand Hills Of Nebraska May 4-6, 1994 Jan 1994

A Field Trip To The Sand Hills Of Nebraska May 4-6, 1994

Conservation and Survey Division: Faculty and Staff Publications

The Sand Hills of central Nebraska, covering over 50,000 sq km (19,300 sq miles) constitute a unique physiographic, geologic and hydrologic province in the United States.

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Cass County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1994

Cass 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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Clay County Test Hole Logs, Raymond R. Burchett Jan 1994

Clay County Test Hole Logs, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 3: Source Of Water Vapor Overlying Pyramid Lake, Larry Benson, J. W. C. White Jan 1994

Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 3: Source Of Water Vapor Overlying Pyramid Lake, Larry Benson, J. W. C. White

United States Geological Survey: Staff Publications

During 1988 and 1989, a series of water-vapor extractions were conducted in the Pyramid Lake basin to determine the source of moisture that overlies the lake. Calculations of the isotopic and water-vapor balances were made from isotopic and meteorological data from the Pyramid Lake and Reno, Nevada, areas. The results indicate that in the warm season, most of the moisture that overlies the lake is derived from evaporation as opposed to advected moisture. Isotopic fluxes at the lake surface can be approximated by climatic data from the lake site, which simplifies the calculation of this input in numerical simulations of …

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Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 2. A Predictive Model Of Δ18O And Δ2H In Pyramid Lake, S. W. Hostetler, Larry Benson Jan 1994

Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 2. A Predictive Model Of Δ18O And Δ2H In Pyramid Lake, S. W. Hostetler, Larry Benson

United States Geological Survey: Staff Publications

A physically based model of variations in δ18O and δ2H in Pyramid Lake is presented. For inputs, the model uses measurements of liquid water inflows and outflows and their associated isotopic compositions and a set of meteorological data (radiative fluxes, air temperature, relative humidity, and windspced). The model simulates change of lake volume, thermal and isotopic stratification, evaporation, and the isotopic composition of evaporation. A validation of the model for 1987-1989 and 1991 indicates that it can reproduce measured intra- and interannual variations of δ18O and δ2H. Three applications of the model …

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Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System. 1. Data Analysis And Extraction Of Paleoclimatic Information, Larry Benson Jan 1994

Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System. 1. Data Analysis And Extraction Of Paleoclimatic Information, Larry Benson

United States Geological Survey: Staff Publications

The δ18O content of streamflow discharge entering Pyramid Lake is a simple mixture of isotopically enriched Lake Tahoe discharge and isotopically depleted snowmelt. The δ18O value of Pyramid Lake water varies continuously, as isotopically depleted water evaporates from the epilimnion and isotopically depicted water enters the lake as streamflow discharge and on-lake precipitation. In a normal water year, the δ18O of Pyramid Lake surface water varies seasonally because the components of the hydrologic balance in the Pyramid Lake system are seasonally shifted. The problem of isotopic and thermal heterogeneity can be minimized by analyzing …

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Initial Reference Models In Local Earthquake Tomography, E. Kissling, W. L. Ellsworth, D. Eberhart-Phillips, U. Kradolfer Jan 1994

Initial Reference Models In Local Earthquake Tomography, E. Kissling, W. L. Ellsworth, D. Eberhart-Phillips, U. Kradolfer

United States Geological Survey: Staff Publications

The inverse problem of three-dimensional (3-D) local earthquake tomography is formulated as a linear approximation to a nonlinear function. Thus the solutions obtained and the reliability estimates depend on the initial reference model. Inappropriate models may result in artifacts of significant amplitude. Here, we advocate the application of the same inversion formalism to determine hypocenters and one-dimensiona(1-D) velocity model parameters, including station corrections, as the first step in the 3-D modeling process. We call the resulting velocity model the minimum 1-D model.  For test purposes,  synthetic data set based on the velocity structure of the San Andreas fault zone in …

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Effects Of Lithology And Depth On The Permeability Of Core Samples From The Kola And Ktb Drill Holes, C. Morrow, D. Lockner, S. Hickman, M. Rusanov, T. Röckel Jan 1994

Effects Of Lithology And Depth On The Permeability Of Core Samples From The Kola And Ktb Drill Holes, C. Morrow, D. Lockner, S. Hickman, M. Rusanov, T. Röckel

United States Geological Survey: Staff Publications

Permeability measurements were conducted on intact core samples from
the Kola drill hole in Russia and the KTB drill hole in Germany. Samples included granodiorite gneisses, basalts and amphibolites from depths up to 11 km. The tests were intended to determine the pressure sensitivity of permeability and to compare the effects of stress relief and thermal microcracking on the matrix permeability of different rock types and similar samples from different depths. The pore pressure Pp was fixed at the estimated in situ pressure assuming a normal hydrostatic gradient;
the confining pressure Pc was varied to produce effective pressures(P …

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Ultrasonic Velocities In Cores From The Kola Superdeep Well And The Nature Of Subhorizontal Seismic Reflections, Lev Vernik, Stephen Hickman, David Lockner, Michael Rusanov Jan 1994

Ultrasonic Velocities In Cores From The Kola Superdeep Well And The Nature Of Subhorizontal Seismic Reflections, Lev Vernik, Stephen Hickman, David Lockner, Michael Rusanov

United States Geological Survey: Staff Publications

P wave velocity and orthogonally polarized S wave velocities were
measured on 12 cores recovered from the Kola superdeep well at depths of 0 to 12 km. Measurements were made along the core axis at a frequency of 1 MHz, at confiningp ressures ranging from 2 to 100 MPa, and under dry and water-saturated conditions. Cores were chosen to sample a variety of lithologies and were used to estimate interval velocities based on a simplified geological column of the well. These interval velocities were then compared with sonic log and vertical seismic profile (VSP) data. High-pressure lab velocities  correlated primarily …

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Herbicide Interchange Between A Stream And The Adjacent Alluvial Aquifer, Wuncheng Wang, Paul Squillace Jan 1994

Herbicide Interchange Between A Stream And The Adjacent Alluvial Aquifer, Wuncheng Wang, Paul Squillace

United States Geological Survey: Staff Publications

Herbicide interchange between a stream and the adjacent alluvial aquifer and quantification of herbicide bank storage during high streamflow were investigated at a research site on the Cedar River flood plain, 10 km southeast of Cedar Rapids, Iowa. During high streamflow in March 1990, alachlor, atrazine, and metolachlor were detected at concentrations above background in water from wells as distant as 20, 50, and 10 m from the river’s edge, respectively. During high streamflow in May 1990, alachlor, atrazine, cyanazine, and metolachlor were detected at concentrations above background as distant as 20, 50, 10, and 20 m from the river’s …

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Groundwater-Level Changes In Nebraska, 1992, Gregory V. Steele, Perry B. Wigley Jan 1994

Groundwater-Level Changes In Nebraska, 1992, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Nebraska Mineral Operations Review, 1993, Raymond R. Burchett, Duane A. Eversoll Jan 1994

Nebraska Mineral Operations Review, 1993, Raymond R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource Notes-Academic Year 1993-94 Jan 1994

Resource Notes-Academic Year 1993-94

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource News-Spring 1994 Jan 1994

Resource News-Spring 1994

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource News-Summer 1994 Jan 1994

Resource News-Summer 1994

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Location Of Registered Irrigation Wells In Nebraska As Of 1994 Jan 1994

Location Of Registered Irrigation Wells In Nebraska As Of 1994

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Further Evidence Of Lead Contamination Of Omaha Skeletons, A. Mohamad Ghazi, Karl J. Reinhard, Mary Anne Holmes, Eric M. Durrance Jan 1994

Further Evidence Of Lead Contamination Of Omaha Skeletons, A. Mohamad Ghazi, Karl J. Reinhard, Mary Anne Holmes, Eric M. Durrance

Department of Earth and Atmospheric Sciences: Faculty Publications

A previous analysis of Omaha skeletons dating between A.D. 1780 and 1820 revealed the presence of lead in all skeletons with high concentrations in children and adult males (Reinhard and Ghazi [1992] Am. J. Phys. Anthropol. 89: 183-195). Two likely explanations for the high lead levels were presented: 1) metabolic absorption of lead and 2) diagenetic uptake of lead by the bones from postmortem application of pigments to the corpse. Two types of lead were available to the Omaha tribe: 1) Mississippi Valley type, and 2) non-Mississippi Valley type. It has been suggested that red-lead pigment mixed with mercury sulfide …

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Home Range And Movement Characteristics Of Female White-Tailed Deer At Desoto National Wildlife Refuge, Kurt C. Vercauteren Dec 1993

Home Range And Movement Characteristics Of Female White-Tailed Deer At Desoto National Wildlife Refuge, Kurt C. Vercauteren

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

No abstract provided.

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Changes In Benthic Invertebrate Composition In Response To Reservoir Aging, Arthur Popp Dec 1993

Changes In Benthic Invertebrate Composition In Response To Reservoir Aging, Arthur Popp

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

No abstract provided.

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Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr. Oct 1993

Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Evidence of the climatic conditions in the mountain sediment source areas for the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska has been sought in an SEM (scanning electron microscope) study of surface features on detrital quartz grains from these deposits. The following lines of indirect evidence raised the possibility of glacial conditions: uplift of up to 3500 m in the source areas, paleohydrologic parameters indicative of a transport system analogous to the modern North Saskatchewan River, and possible cold climate surface features on cobbles from the deposits. SEM analysis shows that five of the nine …

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Epa's Map Of Radon Zones Nebraska, U.S. Environmental Protection Agency's, U.S. Geological Survey Sep 1993

Epa's Map Of Radon Zones Nebraska, U.S. Environmental Protection Agency's, U.S. Geological Survey

United States Environmental Protection Agency: Publications

Sections 301 and 309 of the 1988 Indoor Radon Abatement Act (IRAA) direct EPA to identify areas of the United States that have the potential to produce elevated levels of radon. EPA, the U.S. Geological Survey (USGS), and the Association of. American State Geologists (AASG) have worked closely over the past several years to produce a series of maps and documents which address these directives. The EPA Map of Radon Zones is a compilation of that work and fulfills the requirements of sections 307 and 309 of IRAA. The Map of Radon" Zones identifies, on a county-by-county basis, areas' of …

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Epa's Map Of Radon Zones, Nebraska, Sharon W. White, Lisa Ratcliff, Kirk Maconaughey, R. Thomas Peake, Dave Rowson, Steve Page, Linda C. S. Gundersen, R. Randall Schumann, James K. Otton, Doug Owen, Russell Dubiel, Kendell Dickinson, Sandra L. Szarzi Sep 1993

Epa's Map Of Radon Zones, Nebraska, Sharon W. White, Lisa Ratcliff, Kirk Maconaughey, R. Thomas Peake, Dave Rowson, Steve Page, Linda C. S. Gundersen, R. Randall Schumann, James K. Otton, Doug Owen, Russell Dubiel, Kendell Dickinson, Sandra L. Szarzi

United States Environmental Protection Agency: Publications

Sections 307 and 309 of the 1988 Indoor Radon Abatement Act (IRAA) direct EPA to identify areas of the United States that have the potential to produce elevated levels of radon. EPA, the U.S. Geological Survey (USGS), and the Association of, American State Geologists (AASG) have worked closely over the past several years to produce a series of maps and documents which address these directives. The EPA Map of Radon Zones is a compilation of that work and fulfills the requirements of sections 307 and 309 of IRAA. The Map of Radon Zones identifies, on a county-by-county basis, areas of …

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Limnological And Habitat Influences On Wetland Bird Communities In The Nebraska Sandhills, Timothy A. Cramer Aug 1993

Limnological And Habitat Influences On Wetland Bird Communities In The Nebraska Sandhills, Timothy A. Cramer

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

No abstract provided.

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Geology, Geologic Time And Nebraska, Marvin P. Carlson Aug 1993

Geology, Geologic Time And Nebraska, Marvin P. Carlson

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Groundwater Velocity In An Unconfined Aquifer With Rectangular Areal Recharge, Vitaly A. Zlotnik, Glenn Ledder Aug 1993

Groundwater Velocity In An Unconfined Aquifer With Rectangular Areal Recharge, Vitaly A. Zlotnik, Glenn Ledder

Department of Earth and Atmospheric Sciences: Faculty Publications

Three-dimensionsal solutions for the hydraulic head and velocity components for transient groundwater flow in an unconfined compressible aquifer of finite thickness with a rectangular areal recharge source are analyzed using a linearized mathematical model. The solution generalizes Dagan's (1967) results, which were obtained for an idealized aquifer of infinite thickness, and Hantush's (1967) results, which were derived using the Dupuit assumptions. Hydraulic head and velocity components are estimated by asymptotic methods for large times, which are most appropriate for contaminant transport problems. Numerical analysis of the solution demonstrates spatial features of the velocity components in general and a transient effect …

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Information And Regulations Pertaining To Industrial Minerals In Nebraska, Raymond R. Burchett Jun 1993

Information And Regulations Pertaining To Industrial Minerals In Nebraska, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Understanding Groundwater Starts With The Rocks: Geologic Fralnework, Groundwater Occurrence And Irrigation Development In Nebraska, Robert F. Diffendal Jr. Mar 1993

Understanding Groundwater Starts With The Rocks: Geologic Fralnework, Groundwater Occurrence And Irrigation Development In Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Nebraska is blessed with abundant groundwater. This groundwater is found beneath much of the state, principally in the sediments and sedimentary rocks that blanket the ancient and largely crystalline rocks geologists call Precambrian (see block diagram of Nebraska's geology, p. 50). These younger deposits contain pieces of evidence such as fossils and sedimentary features that reveal the tremendous changes in the environment that have gone on over the last 570 million years, during which these deposits accumulated. Change is the name of the game in geologic history, just as it is in human history. Fundamental changes in geologic history across …

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Profiles: Nelson Horatio Darton: His Surveys Laid The Foundation, Robert F. Diffendal Jr. Mar 1993

Profiles: Nelson Horatio Darton: His Surveys Laid The Foundation, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

No serious researcher studying the development of water resources in Nebraska, or for that matter in the central Great Plains, can overlook the works of Nelson Horatio Darton, the first geologist to study and publish about those resources in any detail. Darton originally published the names and characteristics of many hydrogeologic units beneath much of Nebraska, now used by groups as diverse as scientists, well drillers and the general public. These works are listed below. As an indication of the value of these early efforts, I have used these works for my research and can testify to their accuracy and …

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