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Articles 3151 - 3180 of 4541

Full-Text Articles in Earth Sciences

Earthquakes In Nebraska, R. R. Burchett Jan 1998

Earthquakes In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Oil And Gas Fields In Nebraska, R. R. Burchett Jan 1998

Oil And Gas Fields In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Estimates Of Annual Survival Probabilities For Adult Florida Manatees (Trichechus Manatus Latirostris), C. A. Langtimm, T. J. O'Shea, R. Pradel, C. A. Beck Jan 1998

Estimates Of Annual Survival Probabilities For Adult Florida Manatees (Trichechus Manatus Latirostris), C. A. Langtimm, T. J. O'Shea, R. Pradel, C. A. Beck

United States Geological Survey: Staff Publications

The population dynamics of large, long-lived mammals are particularly sensitive to changes in adult survival. Understanding factors affecting survival patterns is therefore critical for developing and testing theories of population dynamics and for developing management strategies aimed at preventing declines or extinction in such taxa. Few studies have used modern analytical approaches for analyzing variation and testing hypotheses about survival probabilities in large mammals. This paper reports a detailed analysis of annual adult survival in the Florida manatee (Trichechus manatus latirostris), an endangered marine mammal, based on a mark-recapture approach. Natural and boat- inflicted scars distinctively "marked" individual …

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Book Review Of Paleolimnology Of Europeanmaar Lakes By J. F.W. Negendank & B. Zolitschka (Eds)., J. Platt Bradbury Jan 1998

Book Review Of Paleolimnology Of Europeanmaar Lakes By J. F.W. Negendank & B. Zolitschka (Eds)., J. Platt Bradbury

United States Geological Survey: Staff Publications

This book represents a collection of papers presented at a symposium in May, 1991 on the formation and paleolimnology of European maar lakes. Paleolimnological discussions embrace maar lake deposits of late Quaternary to early Tertiary age in Germany, France and Italy. The goal of the symposium and its outgrowth, this book, is to develop a funding initiative to study, core and analyze the deposits of these remarkable depositional systems.

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Observation Of The Seismic Nucleation Phase In The Ridgecrest, California, Earthquake Sequence, William L. Ellsworth, Gregory C. Beroza Jan 1998

Observation Of The Seismic Nucleation Phase In The Ridgecrest, California, Earthquake Sequence, William L. Ellsworth, Gregory C. Beroza

United States Geological Survey: Staff Publications

Near-source observations of five M 3.8-5.2 earthquakes near Ridgecrest, California are consistent with the presence of a seismic nucleation phase. These earthquakes start abruptly, but then slow or stop before rapidly growing again toward their maximum rate of moment release. Deconvolution of instrument and path effects by empirical Green's functions demonstrates that the initial complexity at the start of the earthquake is a source effect. The rapid growth of the P-wave arrival at the start of the seismic nucleation phase supports the conclusion of Mori and Kanamori [1996] that these earthquakes begin without a magnitude-scaled slow initial phase of the …

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Continuous Lake-Sediment Records Of Glaciation In The Sierra Nevada Between 52,600 And 12,500 14c Yr B.P., Larry Benson, Howard M. May, Ronald C. Antweiler, Terry I. Brinton, Michaele Kashgarian, Joseph P. Smoot, Steve P. Lund Jan 1998

Continuous Lake-Sediment Records Of Glaciation In The Sierra Nevada Between 52,600 And 12,500 14c Yr B.P., Larry Benson, Howard M. May, Ronald C. Antweiler, Terry I. Brinton, Michaele Kashgarian, Joseph P. Smoot, Steve P. Lund

United States Geological Survey: Staff Publications

The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial-interstadial oscillations, Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ~24,500 and ended by ~13,600 14C yr B.P. Many of the components of glacial rock flour (e.g., TiO2 , MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and Si02 (amorphous) concentrations reached minimum values …

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Early Life History Stages Of Gulf Sturgeon In The Suwannee River, Florida, Kenneth J. Sulak, James P. Clugston Jan 1998

Early Life History Stages Of Gulf Sturgeon In The Suwannee River, Florida, Kenneth J. Sulak, James P. Clugston

United States Geological Survey: Staff Publications

Egg sampling confirmed that Suwannee River Gulf sturgeon Acipenser ozyrinchus desotoi, a subspecies of Atlantic sturgeon A. o. oxyrinchus use the same spawning site at river kilometer (rkm) 215 from the mouth of the river each year. Forty-nine eggs were recorded in 1995, and 368 were recorded in 1996. Spawning began 4-7 d after the March new moon in both years and lasted 10-11 d; in 1996, a second 10-d spawning round began on the April new moon. Developmental synchrony among eggs recovered suggested serval discrete spawning events in both years. Total eggs deposited for three 1996 sampling days …

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Subsurface Heavy-Metal Detection With The Use Of A Laser-Induced Breakdown Spectroscopy (Libs) Penetrometer System, Brian Miles, Javier Cortes Jan 1998

Subsurface Heavy-Metal Detection With The Use Of A Laser-Induced Breakdown Spectroscopy (Libs) Penetrometer System, Brian Miles, Javier Cortes

United States Army Corps of Engineers, Omaha District

U.S. Army Engineer Waterways Experiment Station (WES) investigators have designed, fabricated, and demonstrated a cone penetrometer sensor for subsurface in situ field screening based on LIBS. The LIBS probe (patent pending) presented here is one of a suite of contaminant and geophysical probes developed by the WES Site Characterization and Analysis Penetrometer System (SCAPS) program. The LIBS probe includes a laser as part of the optical LIBS sensor section for metals analysis and a cone and sleeve soil classification module at its tip. Soil classification data are acquired during the push, while LIBS data are recorded during probe retraction, after …

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Stable Isotopes And Sediments From Pickerel Lake, South Dakota, Usa: A 12ky Record Of Environmental Changes, Antje Schwalb, Walter E. Dean Jan 1998

Stable Isotopes And Sediments From Pickerel Lake, South Dakota, Usa: A 12ky Record Of Environmental Changes, Antje Schwalb, Walter E. Dean

United States Geological Survey: Staff Publications

Sedimentological parameters and stable O- and C-isotopic composition of marl and ostracode calcite selected from a 17.7 m long core from the 8 m deep center of Pickerel Lake, northeastern South Dakota, provide one of the longest (ca. 12ky) paleoenvironmental records from the northern Great Plains. The late Glacial to early Holocene climate in the northern Great Plains was characterized by changes from cold and wet to cold and dry, and back to cold and wet conditions. These climatic changes were controlled by fluctuations in the positions of the Laurentide ice sheet and the extent of glacial Lake Agassiz. We …

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Determination Of Bioavailable Contaminants In The Lower Missouri River Following The Flood Of 1993, Jimmie Petty, Barry Poulton, Colette Charbonneau, James Huckins, Susan Jones, Jennifer Cameron, Harry Prest Jan 1998

Determination Of Bioavailable Contaminants In The Lower Missouri River Following The Flood Of 1993, Jimmie Petty, Barry Poulton, Colette Charbonneau, James Huckins, Susan Jones, Jennifer Cameron, Harry Prest

United States Geological Survey: Staff Publications

The semipermeable membrane device (SPMD) technology was employed to determine the presence of bioavailable organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs) in the water of the main stem of the lower Missouri River and three of its tributaries. The SPMDs were deployed in 1994 following the extensive flood of 1993. Specifically, the SPMDs were deployed for 28 days at Wilson State Park, IA; Nebraska City, NE; Parkville, MO; the Kansas River in Kansas City, KS; Napoleon, MO; the Grand River; Glasgow, MO; the Missouri River upstream from the confluence of the Gasconade River; the Gasconade River; and …

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Occurrence Of Pesticides In Shallow Groundwater Of The United States: Initial Results From The National Water-Quality Assessment Program, Dana Kolpin, Jake Barbash, Robert Gilliom Jan 1998

Occurrence Of Pesticides In Shallow Groundwater Of The United States: Initial Results From The National Water-Quality Assessment Program, Dana Kolpin, Jake Barbash, Robert Gilliom

United States Geological Survey: Staff Publications

The first phase of intensive data collection for the National Water-Quality Assessment (NAWQA) was completed during 1993-1995 in 20 major hydrologic basins of the United States. Groundwater land-use studies, designed to sample recently recharged groundwater (generally within 10 years) beneath specific land-use and hydrogeologic settings, are a major component of the groundwater quality assessment for NAWQA. Pesticide results from the 41 land use studies conducted during 1993-1995 indicate that pesticides were commonly detected in shallow groundwater, having been found at 54.4% of the 1034 sites sampled in agricultural and urban settings across the United States. Pesticide concentrations were generally low, …

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Seismic Rock-Physics Model For Carbonates At Low Effective Stress Levels Jan 1998

Seismic Rock-Physics Model For Carbonates At Low Effective Stress Levels

United States Geological Survey: Staff Publications

When considering the seismic response from the Dammam aquifer, the first required component is a simple model relating porosity and stress state to frame moduli assuming a carbonate matrix. We explored two such relationships, one based on the empirical regression presented by Domenico (1984) and a second using the critical porosity model of Nur et al. (1998) calibrated to the ultrasonic measurements of Nur and Simmons (1969). Once frame properties for a given porosity/pressure state were estimated, the effect of fluid changes were calculated using the low-frequency form of the Biot-Gassmann model, better known as Gassmann fluid substitution (Mavko …

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Evolution Of The Aeluroid Carnivora: Diversity Of The Earliest Aeluroids From Eurasia (Quercy, Hsanda-Gol) And The Origin Of Felids, Robert M. Hunt Jr. Jan 1998

Evolution Of The Aeluroid Carnivora: Diversity Of The Earliest Aeluroids From Eurasia (Quercy, Hsanda-Gol) And The Origin Of Felids, Robert M. Hunt Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

The oldest known fossil aeluroids are from Lower Oligocene sediments in France (Quercy) and Upper Eocene-Lower Oligocene sediments in Mongolia. These small (< 5 kg) carnivorans are primarily represented by mandibles, with hypercarnivorous dentitions in almost all lineages. The six aeluroid genera from France and those from Mongolia share a common dental pattern despite their geographic separation near the extremes of the Eurasian landmass. This similarity is not surprising, however, because faunal exchange across Eurasia at this time is documented not only by populations of small aeluroids but also by small arctoid carnivorans. Basicrania of Oligocene aeluroids are preserved only in the Quercy deposits. The auditory regions of two genera from Quercy (Palaeoprionodon, Stenoplesictis), and of two additional aeluroid genera (Stenogale, Proailurus) known only from mandibles at Quercy (but matched with congeneric mandibles with associated basicrania from early Miocene sediments at St.-Gerand), reveal a common basicranial morphotype. The living African palm civet Nandinia binotata retains a basicranial and auditory anatomy closely approaching the ancestral aeluroid morphotype. European paleontologists working with the Quercy faunas have regarded several of these aeluroids as early members of the Viverridae and …

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Amphicyonidae, Robert Hunt Jan 1998

Amphicyonidae, Robert Hunt

University of Nebraska State Museum: Mammalogy Papers

The Amphicyonidae occur in North America from late Eocene (~40 Ma) to early late Miocene (~9 Ma), a span of 31 million years. In the North American land mammal biochronology, this diverse family extends from the Duchesnean to the end of the Clarendonian and is especially well represented in the Miocene (~5-24 Ma). In the Old World, amphicyonids survive no longer than in North America: The last European records are Vallesian (Dinotheriensande, Mainz Basin, Germany, Kuss, 1965, Tobien, 1980; Vallés-Penédes Basin, Spain, Crusafont-Pairó and Kurten, 1976), and the last representative may occur at about 9 Ma at Kohfidisch, Austria (latest …

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Estimation Of Suspended Sediment Concentration In Water Using Integrated Surface Reflectance, Mahtab A. Lodhi, Donald C. Rundquist, Luoheng Han, Mark S. Kuzila Jan 1998

Estimation Of Suspended Sediment Concentration In Water Using Integrated Surface Reflectance, Mahtab A. Lodhi, Donald C. Rundquist, Luoheng Han, Mark S. Kuzila

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource News-Winter 1997-98 Jan 1998

Resource News-Winter 1997-98

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource News-Spring 1998 Jan 1998

Resource News-Spring 1998

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Mineral Facts For Nebraska, Excluding Oil And Gas, R. R. Burchett Jan 1998

Mineral Facts For Nebraska, Excluding Oil And Gas, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Oil And Gas Facts For Nebraska, R. R. Burchett Jan 1998

Oil And Gas Facts For Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Twin Platte Natural Resources District Groundwater Quality Study, D. C. Gosselin, L. Howard, J. Goeke Jan 1998

Twin Platte Natural Resources District Groundwater Quality Study, D. C. Gosselin, L. Howard, J. Goeke

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Colfax County Test Hole Logs, Frank A. Smith, Raymond R. Burchett Jan 1998

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Dodge County Test Hole Logs, Frank A. Smith, Raymond R. Burchett Jan 1998

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Harlan County Test Hole Logs, Raymond R. Burchett Jan 1998

Harlan County Test Hole Logs, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Washington County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1998

Washington 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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Platte County Test Hole Logs, Raymond R. Burchett, Scott E. Summerside Jan 1998

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Cadmium Malonate Complexation In Aqueous Sodium Trifluoromethanesulfonate Media To 75°C; Including Dissociation Quotients Of Malonic Acid, Moira K. Ridley, Donald A. Palmer, David J. Wesolowski, Richard Kettler Jan 1998

Cadmium Malonate Complexation In Aqueous Sodium Trifluoromethanesulfonate Media To 75°C; Including Dissociation Quotients Of Malonic Acid, Moira K. Ridley, Donald A. Palmer, David J. Wesolowski, Richard Kettler

Department of Earth and Atmospheric Sciences: Faculty Publications

The molal formation quotients for cadmium-malonate complexes were measured potentiometrically from 5 to 75°C, at ionic strengths of 0.1, 0.3, 0.6 and 1.0 molal in aqueous sodium trifluoromethanesulfonate (NaTf) media. In addition, the stepwise dissociation quotients for malomc acid were measured in the same medium from 5 to 100°C, at ionic strengths of 0.1, 0.3, 0.6, and 1.0 molal by the same method. The dissociation quotients for malonic acid were modeled as a function of temperature and ionic strength with empirical equations formulated such that the equilibrium constants at infinite dilution were consistent, within the error estimates, with the malonic …

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Upper Cenozoic Calcareous Nannofossil Biostratigraphy Côte D'Ivoire-Ghana Margin, Eastern Equatorial Atlantic, Samir Shafik, David K. Watkins, Im Chul Shin Jan 1998

Upper Cenozoic Calcareous Nannofossil Biostratigraphy Côte D'Ivoire-Ghana Margin, Eastern Equatorial Atlantic, Samir Shafik, David K. Watkins, Im Chul Shin

Department of Earth and Atmospheric Sciences: Faculty Publications

The distribution of calcareous nannofossils in the upper Cenozoic sections sampled at four sites in the eastern equatorial Atlantic Ocean during Ocean Drilling Program (ODP) Leg 159 is documented here. A virtually complete upper Cenozoic sequence of nannofossil (sub)zones is identified at Site 959 on the shoulder of the Côte d’Ivoire-Ghana marginal ridge, with proxies for the rare marker species being employed. Hiatuses within the middle and upper Miocene are detected at two other sites on the same ridge, being more clearly defined at Site 960 on the crest of the ridge. Two of these hiatuses are of regional significance. …

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Calcareous Nannofossils From The Cretaceous Of The Deep Ivorian Basin, David K. Watkins, Samir Shafik, Im Chul Shin Jan 1998

Calcareous Nannofossils From The Cretaceous Of The Deep Ivorian Basin, David K. Watkins, Samir Shafik, Im Chul Shin

Department of Earth and Atmospheric Sciences: Faculty Publications

Micropaleontological investigation of four sites drilled by Ocean Drilling Program Leg 159 on the Côte d’Ivoire-Ghana Margin indicates that the initial invasion of oceanic surface waters into the Deep Ivorian Basin, as indicated by the presence of calcareous nannofossils, occurred during the late Albian. The nature of these assemblages suggests that these first Cretaceous oceanic surface waters were warm and relatively high in nutrients. These upper Albian sediments were deposited prior to significant tectonism at some of the sites, as indicated by their structurally deformed nature. The likely age of this tectonism is Cenomanian. The Upper Cretaceous consists of condensed …

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High-Resolution Pliocene–Pleistocene Biostratigraphy Of Site 959, Eastern Equatorial Atlantic Ocean, Im Chul Shin, Samir Shafik, David K. Watkins Jan 1998

High-Resolution Pliocene–Pleistocene Biostratigraphy Of Site 959, Eastern Equatorial Atlantic Ocean, Im Chul Shin, Samir Shafik, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

High-resolution calcareous nannofossil biostratigraphy was examined from Cores 159-959C-1H through 8H in 20-cm intervals for the Ocean Drilling Program in the eastern equatorial Atlantic Ocean. Well-preserved marker species occur continuously and are relatively abundant in Hole 959C. Six zones (CN10 through CN15) are identified. All calcareous nannofossils are well preserved. Late Neogene (Pliocene–Pleistocene) sediment is dominated by Florisphaera profunda, Gephyrocapsa caribbeanica, G. oceanica, Gephyrocapsa spp., Reticulofenestra pseudoumbilica, R. minutula, and small Reticulofenestra. The sedimentation rate varies from 0.4 cm/k.y. to 13.5 cm/k.y. This strong variations are related to disconformities. The lowest sedimentation rate occurs in the early late …

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Oligocene To Early Miocene Silicoflagellates From The Ivorian Basin, Eastern Equatorial Atlantic, Site 959, Maija E. Schellpeper, David K. Watkins Jan 1998

Oligocene To Early Miocene Silicoflagellates From The Ivorian Basin, Eastern Equatorial Atlantic, Site 959, Maija E. Schellpeper, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

Silicoflagellate biostratigraphy and relative abundance were determined for Site 959 in the eastern equatorial Atlantic. Five silicoflagellate zones, Corbisema apiculata, Naviculopsis biapiculata, Naviculopsis lata, Naviculopsis ponticula, and Corbisema triacantha Zones, were used with the Distephanus speculum hemisphaericus Subzone occurring in the N. biapiculata Zone. The Naviculopsis quadrata Zone is missing between the N. ponticula and N. lata Zones, indicating a hiatus in the lower Miocene cores that corresponds to hiatus NH1. Silicoflagellate relative abundance was graphed as a measure of paleoproductivity for Hole 959A. One large pulse of productivity occurred in the latest early Miocene, right before silica deposition …

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