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Articles 16381 - 16410 of 17789
Full-Text Articles in Entire DC Network
Bermuda Solution Pipe Soils: A Geochemical Evaluation Of Eolian Parent Materials, Stanley R. Herwitz, Daniel R. Muhs
Bermuda Solution Pipe Soils: A Geochemical Evaluation Of Eolian Parent Materials, Stanley R. Herwitz, Daniel R. Muhs
United States Geological Survey: Staff Publications
Solution pipes found in the Quaternary eolian and marine carbonates of Bermuda are filled with reddish to reddish-brown soil material. The bulk of the soil is composed of clay and silt-sized quartz and aluminosilicate clay minerals. The carbonates are of high purity and, therefore, are not likely to have been the parent material. Previous workers have hypothesized that Saharan dust may have been the soil parent material. The fine-grained component of loess from the Mississippi River Valley of North America also could have contributed. Paleoclimate models indicate that both North Africa and North America could have been important source areas …
Organic Facies And Maturation Of Jurassic/Cretaceous Rocks, And Possible Oil-Source Rock Correlation Based On Pyrolysis Of Asphaltenes, Scotian Basin, Canada, Prasanta K. Mukhopadhyay, John A. Wade, Michael A. Kruge
Organic Facies And Maturation Of Jurassic/Cretaceous Rocks, And Possible Oil-Source Rock Correlation Based On Pyrolysis Of Asphaltenes, Scotian Basin, Canada, Prasanta K. Mukhopadhyay, John A. Wade, Michael A. Kruge
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
This paper establishes source rock characterization and oil-oil and oil-source rock correlations of selected organic-rich shale source rocks and selected light oils and condensates from Jurassic and Cretaceous formations of the Scotian Basin. Multiple source rocks of Kerogen Types IIA (oil-prone), IIA-IIB (oil- and condensate-prone), IIB (condensate and gas prone), III (gas-prone), and IV (nonsource) are identified in various stratigraphic horizons. Vitrinite reflectance and Tmax data indicate variable maturation histories, in different parts of the basin, which are related to differences in lithology-related heat conductivity and the presence of older sediments closer to areas of rifting. Multiple linear regression …
Atrazine And Alachlor Dissipation Rates From Field Experiments, Stephen R. Workman, Andrew D. Ward, Norman R. Fausey, Sue E. Nokes
Atrazine And Alachlor Dissipation Rates From Field Experiments, Stephen R. Workman, Andrew D. Ward, Norman R. Fausey, Sue E. Nokes
Biosystems and Agricultural Engineering Faculty Publications
Chemical transport is being monitored in the root zone of three agricultural management systems at the Ohio Management Systems Evaluation Area (OMSEA). Atrazine and alachlor concentration data from soil cores taken to a depth of 0.9 m and partitioned into the increments of 0.0 to 0.15, 0.15 to 0.3, 0.45 to 0.6, and 0.75 to 0.9 m show the herbicides remained in the top 0.15 m of the profile during the 1991 and 1992 growing seasons. The slow movement of herbicides was partly due to below normal rainfall during the period. Since the herbicides have not been transported out of …
Elimination Of Dissolved Sulfide Interference In The Flow-Injection Determination Of Sigma-Co2 By Addition Of Molybdate, Rigel L. Lustwerk, David J. Burdige
Elimination Of Dissolved Sulfide Interference In The Flow-Injection Determination Of Sigma-Co2 By Addition Of Molybdate, Rigel L. Lustwerk, David J. Burdige
OES Faculty Publications
A previously described flow injection method for the analysis of ΣCO2 included the addition of ZnCl2 to some samples before analysis in order to precipitate dissolved sulfide (which interferes with the method) as ZnS. However, the use of Zn2+ in samples with high concentrations of dissolved sulfide causes the coprecipitation of ZnCO3, and in our experience with this technique, ZnCO3 also precipitates even in the absence of dissolved sulfide. The addition of molybdate effectively complexes dissolved sulfide without interfering with the determination of ΣCO2 by this technique.
Prey Selectivity By Naticid Gastropods From Tertiary Sediments Of The United States Coastal Plain, Robert N. Sickler
Prey Selectivity By Naticid Gastropods From Tertiary Sediments Of The United States Coastal Plain, Robert N. Sickler
Theses and Dissertations
Previous studies have shown that naticid gastropod predators are highly selective of prey species in accordance with the Kitchell et al. (1981) cost-benefit model. In addition, earlier studies have demonstrated selectivity of drillhole siting and intraspecific prey size. This study focuses on prey selectivity by Oligocene naticid gastropods and is used to test Vermeij's (1987) hypothesis of escalation. The hypothesis of escalation states that biologic hazards have increased during the Phanerozoic and that organisms have either had to adapt to these hazards or face possible extinction (Vermeij, 1987). Naticid predation on molluscan assemblages is one of several examples used to …
Freezing And Thawing Of Agricultural Soils: Implications For Soil, Water, And Air Quality, Brenton S. Sharratt, Keith E. Saxton, Jerry K. Radke
Freezing And Thawing Of Agricultural Soils: Implications For Soil, Water, And Air Quality, Brenton S. Sharratt, Keith E. Saxton, Jerry K. Radke
Journal of the Minnesota Academy of Science
Most agricultural lands in the USA are subject to subfreezing temperatures. Soil freezing and thawing affects both biotic and abiotic interactions and processes which vary with weather, soil type, land management, and topography. Soil fauna generally undergo physiological changes or rely on locomotion as a means of adapting to frozen soils. Managing faunal populations using soil management may be achievable with a better understanding of winter ecological processes. Many of the thermal, hydraulic, mechanical, and physical properties of soils are altered by freezing and thawing. Soil erosion may be accentuated by soil freezing and thawing as a result of changes …
Studies On Freezing And Thawing Soils In Iowa, Jerry K. Radke, Edwin C. Berry
Studies On Freezing And Thawing Soils In Iowa, Jerry K. Radke, Edwin C. Berry
Journal of the Minnesota Academy of Science
Frozen soils have a major influence on the cropping systems and farming practices in northern states. However, relatively little research has been done on the physical, chemical, and biological processes that occur in the field during the non-growing season. Experiments on frozen soils were started recently in Iowa to 1) study the effects of residue cover on soil freezing and thawing, 2) measure the movement of water and solutes and changes in soil structure due to freezing and thawing of repacked soil columns in the field, 3) test the SHAW (Simultaneous Heat And Water) model for its capability to predict …
Frozen Soils: A Perspective On Past And Future Research For Promoting Sustainable Agricultural Systems, Jerry K. Radke, Brenton S. Sharratt, W. Doral Kemper, Dale A. Bucks
Frozen Soils: A Perspective On Past And Future Research For Promoting Sustainable Agricultural Systems, Jerry K. Radke, Brenton S. Sharratt, W. Doral Kemper, Dale A. Bucks
Journal of the Minnesota Academy of Science
Frozen soils impact many industries which rely· on soil, water, and .air resources in developing and manufacturing products. Most noteworthy is the agricultural industry in the northern United States where soils, which sustain food and fiber production, are subjected to frequent freezing and thawing. Soil freezing and thawing influences soil erodibility, surface and ground water quality, air quality, and biological activity. Many strides toward understanding frozen soil processes and managing lands to minimize the adverse effects of freezing and thawing have been made over the last two decades. Yet, further efforts to identify frozen soil processes which influence wind and …
Morphological Indicators Of Seasonally-Saturated Soils For A Hydrosequence In Southeastern Minnesota, J. C. Bell, J. A. Thompson, C. A. Butler
Morphological Indicators Of Seasonally-Saturated Soils For A Hydrosequence In Southeastern Minnesota, J. C. Bell, J. A. Thompson, C. A. Butler
Journal of the Minnesota Academy of Science
The duration and depth of seasonal soil saturation affects soil suitability for many landuses and are critical factors in the determination of hydric soil boundaries for jurisdictional wetland delineations. Biochemical processes in saturated, anaerobic soil conditions lead to the genesis of soil morphological features that indicate the duration of seasonal saturation. However, few prior studies confirm the relationships between soil hydrology and soil morphology in Minnesota landscapes. We monitored water table and piezometric elevations, soil temperature, redox potential, and soil matric potential at multiple depths for five locations along a hillslope hydrosequence of well to very poorly drained prairie soils …
Modern Marine Sediments Of Bahia Concepcion: Patterns, Processes, And Potential Analogues To Neogene Rift Basin Deposits Of Baja California, Timothy William Reardon
Modern Marine Sediments Of Bahia Concepcion: Patterns, Processes, And Potential Analogues To Neogene Rift Basin Deposits Of Baja California, Timothy William Reardon
Honors Papers
Neogene strata in Baja California preserve a record of extensional basins produced during early phases of rifting in the Gulf of California. This actualistic study addresses the feasibility of using Holocene sediments of Bahia Concepcion - a rift basin forming a shallow marine bay In southern Baja California - as analogues for the interpretation of Neogene strata in the Pliocene Loreto Basin. Three major lithofacies occur in Bahia Concepcion: Mud sediments dominate most of the central portion of the bay. Moderately sorted sands occur adjacent to shorelines formed by coalesced alluvial fans and a broad alluvial plain, while carbonate sands …
Land Management Report For The Kent River Catchment, Sue Kelly
Land Management Report For The Kent River Catchment, Sue Kelly
Natural resources published reports
The Kent River Catchment is located in the South-West of Western Australia, approximately between latitudes 34° 15' and 35° 10' South and longitudes 116° 45" and 117° 50° East. The north-eastern boundary of the catchment stretches to the Albany Highway at Tenterden, and from there the catchment curves towards Rocky Gully before continuing to the South Coast (Figure 1.1.1). The catchment is located within the Shires of Cranbrook, Plantagenet and Denmark.
The Kent River Catchment is part of Basin 604, which is the Water Authority descriptor for the Kent, Bow and Kordabup River catchments collectively. Basin 604 has a total …
Avian Use Of Riparian Corridors And Adjacent Cropland In East-Central Nebraska, Rebecca L. Fitzmaurice
Avian Use Of Riparian Corridors And Adjacent Cropland In East-Central Nebraska, Rebecca L. Fitzmaurice
School of Natural Resources: Dissertations, Theses, and Student Research
No abstract provided.
Initial Transgressive Phase Of Leg 144 Guyots: Evidence Of Extreme Sulfate Reduction, Bjørn Buchardt, Mary Anne Holmes
Initial Transgressive Phase Of Leg 144 Guyots: Evidence Of Extreme Sulfate Reduction, Bjørn Buchardt, Mary Anne Holmes
Department of Earth and Atmospheric Sciences: Faculty Publications
The initial transgressive phase at the Leg 144 Guyots is characterized by a typical association of sedimentary facies (from bottom to top): in situ weathered volcanic rocks; variegated clays, partly pyritic; gray clay, pyritic, homogeneous, or mottled; black clay, peaty, laminated, or bioturbated; and marine argillaceous limestone. Site 877 at Wodejebato Guyot represents the typical development of the initial transgressive phase. The black clay is rich in organic carbon (up to 40%) and sulfur (up to 25%). The organic matter is dominantly of terrestrial origin, but it has a significant marine, algal input. The variegated clays consist of a red, …
Glacial Deposits, Vol. 23, 1994-1995, Department Of Geography-Geology
Glacial Deposits, Vol. 23, 1994-1995, Department Of Geography-Geology
Glacial Deposits
Newsletter of the Department of Geography-Geology
Dissociation Quotients Of Succinic Acid In Aqueous Sodium Chloride Media To 225°C, Richard Kettler, Donald A. Palmer, David J. Wesolowski
Dissociation Quotients Of Succinic Acid In Aqueous Sodium Chloride Media To 225°C, Richard Kettler, Donald A. Palmer, David J. Wesolowski
Department of Earth and Atmospheric Sciences: Faculty Publications
The first and second molal dissociation quotients of succinic acid were measured potentiometrically with a hydrogen-electrode, concentration cell. These measurements were carried out from 0 to 225"C over 25 ° intervals at five ionic strengths ranging from 0.1 to 5.0 molal (NaCl). The dissociation quotients from this and two other studies were combined and treated with empirical equations to yield the following thermodynamic quantities for the first acid dissociation equilibrium at 25°C: logK1a = -4.210±0.003; Δ H1̊a = 2.9±0.2 kJ-mol - 1 ; ΔS1̊a = -71±1 J-mol - 1 -K -1; and ΔCp̊,1a = -98±3 …
Soil Information Sheets For Ravensthorpe And Part Of The Jerramungup Agricultural Areas, Tim D. Overheu, Landcare Western Australia.
Soil Information Sheets For Ravensthorpe And Part Of The Jerramungup Agricultural Areas, Tim D. Overheu, Landcare Western Australia.
Agriculture reports
The soil information sheets produced for the Ravensthorpe Land Conservation District provide an easy reference guide to the soils for part of the Jerramungup and Ravensthorpe agricultural areas, and provide land use and soil management recommendations. Soil data are shown on the front of the sheet, and land use and land management information is given on the back. The information should be used as a guide, and encourage the user to seek further information through the relevant people and organisations.
Birds Of The Platte, Eileen M. Kirsch
Birds Of The Platte, Eileen M. Kirsch
United States Geological Survey: Staff Publications
Gary Lingle has done an outstanding job compiling information to make birding the Central Platte River and Rainwater Basin area of Nebraska easier and more rewarding. The book was not designed to replace a field guide. Rather, it provides maps, general information about the area, when and where birds can be seen, and likelihood of viewing each of 300 bird species possible. Sprinkled throughout the book are drawings by William S. Whitney and Ernest V. Ochsner that depict the structural simplicity of the prairie and the diversity of its wildlife. The writing style is personal and unpretentious, and the text …
19. Pedogenic Alteration Of Basalts Recovered During Leg 144, Mary Anne Holmes
19. Pedogenic Alteration Of Basalts Recovered During Leg 144, Mary Anne Holmes
Department of Earth and Atmospheric Sciences: Faculty Publications
Basalts erupted to form the atolls and guyots of the Western Pacific have been altered in various ways, ranging from hydrothermal alteration to subaerial weathering by meteoric waters in a tropical environment. Subaerial weathering has been moderate to extreme. Moderate subaerial weathering is expressed by dissolution or replacement of primary minerals (olivine, pyroxenes, plagioclase feldspar) and alteration of glassy or aphanitic matrix to clay minerals, goethite, and hematite. The clay minerals are kaolinite or a brown smectite. Kaolinite concentrations decrease downhole and smectite concentrations increase. Although primary minerals are generally not preserved, primary structures, such as vesicles (generally filled by …
Constructed Wetland Design Criteria : A Study Of Their Role In Contaminant Removal From Urban Stormwater Runoff, A. J. Braid
Constructed Wetland Design Criteria : A Study Of Their Role In Contaminant Removal From Urban Stormwater Runoff, A. J. Braid
Theses : Honours
This study was conducted to review effective design criteria for constructed wetlaads treating urban stormwater and to assess the design features of local constructed wetlands in relation to the theoretically ideal design features. The study was generated out of Water Authority of Western Australia (WAWA) concern that existing inconsistent design criteria may result in constructed wetlands not meeting contaminant removal objectives. Three components to the study involved: design criteria compiled from a critical review of relevant literature, field assessment of selected sites with significant differences in design, and a design critique of those sites based on the compiled design criteria. …
The Paleoecologic Significance Of Paleocene Palynomorph Assemblages From The Ludow, Slope, And Cannonball Formations, Southwestern North Dakota, Timothy J. Kroeger
The Paleoecologic Significance Of Paleocene Palynomorph Assemblages From The Ludow, Slope, And Cannonball Formations, Southwestern North Dakota, Timothy J. Kroeger
Theses and Dissertations
Paleoenvironment exerted control on the distribution of 133 palynomorph taxa from the Ludlow and Slope Formations and Boyce and Three V Tongues of the Cannonball Formation (Fort Union Group, I Paleocene) of southwestern North Dakota. The strata represent fluvial deltaic systems that prograded eastward into the Cannonball Sea. Depositional environments include distributary channels, crevasse splays, crevasse-splay feeder channels, lignite-producing swamps and/or marshes, lakes, brackish to slightly brackish bays, lake and bay fills, and marshes
Paleoenvironmentally sensitive palynomorph taxa were identified by subjective examination of pollen diagrams and objective analysis using detrended correspondence analysis. Two paleoenvironmentally restricted palynomorph associations were recognized. …
Karst In Siliceous Rocks: The Speleothem Medium Of Finger Flutings And Its Isotopic Geochemistry, Robert G. Bednarik
Karst In Siliceous Rocks: The Speleothem Medium Of Finger Flutings And Its Isotopic Geochemistry, Robert G. Bednarik
International Journal of Speleology
The isotopic geochemistry relating to the re-precipitation of calcite in caves is considered, in terms of its theory, natural manifestations, and relationship with questions of radiometric dating of carbonate speleothems. Specific forms of’ such deposits are considered, together with the various modification processes they are subjected to. More specifically, particular forms of rock art found within, as well as on or under such deposits are examined, such as finger flutings commonly found in caves of Europe and Australia. Some of the variables relating to their occurrence are elucidated, their preservation and possible dating is reviewed in the light of these …
Indicators Of Nutrient Limited Plankton Growth In Lakes Near Mount Saint Helens, Washington, Kurt Davis Carpenter
Indicators Of Nutrient Limited Plankton Growth In Lakes Near Mount Saint Helens, Washington, Kurt Davis Carpenter
Dissertations and Theses
Several lakes located in the blast zone of the 1980 eruption of Mount St. Helens were studied to determine if the plankton in the lakes were limited in their growth by nitrogen or phosphorus availability. Long term nutrient enrichment experiments were performed on lake water from five lakes and measures of chlorophyll-a, carbon fixation, and nutrient uptake were used to evaluate the extent of limitation. Nutrient concentrations, ratios, and uptake from 14 lakes provided additional evidence for limitation by nitrogen and/or phosphorus. The physical, chemical, and biological characteristics of the lakes were also examined to monitor the return of these …
Subsurface Glacial Geology Of The Area Between The Tekonsha And Kalamazoo Moraines, Kalamazoo County, Michigan, Kim Finkbeiner
Subsurface Glacial Geology Of The Area Between The Tekonsha And Kalamazoo Moraines, Kalamazoo County, Michigan, Kim Finkbeiner
Masters Theses
Cross sections profiling the stratigraphy of the glacial sediments were created using the geological logs recorded on water well records. Glacial sediments in the study area comprise a large outwash complex between two moraines. The surficial landforms are the result of the last Wisconsinan advance and retreat through the area.
Cross sections contructed for this project reveal at least three major till units. An additional till unit contains a weathered soil sequence. Therefore, it is possible that this paleosol represents the Sangamon Interglacial period between the Wisconsinan and Illinoian stages. No obvious evidence of movement of the Saginaw Lobe remains …
Hydrogeological And Hydrochemical Characterization Of The Matozinhos-Pedro Leopoldo Karst, Brazil, Augusto Auler
Hydrogeological And Hydrochemical Characterization Of The Matozinhos-Pedro Leopoldo Karst, Brazil, Augusto Auler
Masters Theses & Specialist Projects
The Matozinhos-Pedro Leopoldo limestone area is a tropical karst located near the metropolis of Belo Horizonte, East Central Brazil, in an area undergoing rapid urbanization and land degradation. Qualitative dye tracing experiments have determined the groundwater routes and catchment areas in the two major drainage basins in the area, Samambaia Basin and Palmeiras-Mocambo Basin. Other drainage basins were identified, but not traced due to the absence of related swallets. Fluorescein and optical brightener had a poor performance as tracers under tropical climate. Dilution due to the existance of lakes at some swallets prevented some dye traces. The water that flows …
Use Of Riparian Vegetated Filter Strips To Reduce Nitrate And Fecal Contamination In Surface Water, Mark S. Coyne, Robert L. Blevins, Rebecca A. Gilfillen
Use Of Riparian Vegetated Filter Strips To Reduce Nitrate And Fecal Contamination In Surface Water, Mark S. Coyne, Robert L. Blevins, Rebecca A. Gilfillen
KWRRI Research Reports
This research assessed fecal bacteria trapping in surface runoff by grass filters and their potential to enhance NO3- removal via denitrification. Grass filter strips 9.0 m long trapped over 99% of the soil in surface runoff in 1992. Fecal coliform removal was less than 75%. In 1993, 9.0 and 4.5 m grass filter strips trapped 99 and 95% of the sediment, respectively. Fecal coliform trapping efficiency was 90% in 9.0 m grass filters and 75% in 4.5 m filters. Fecal streptococci trapping efficiency was 77% in 9.0 m grass filters and only 56% in 4.5 m filters. Fecal …
Earth News, Fall 1994, Department Of Earth Science, University Of Northern Iowa.
Earth News, Fall 1994, Department Of Earth Science, University Of Northern Iowa.
Earth News
Inside this issue:
--- Year in Review
--- Staff News
--- Earth Science Seminar Series Spring Semester, 1994
--- Earth Science Seminar Series Fall Semester, 1994
--- Graduating Seniors
--- Earth Science Department to Host W.I.M.P.S.
--- Sigma Gamma Epsilon
--- News from Alumni
--- Seasons Greetings from the Department of Earth Science
Phosphorus Immobilization In Poultry Litter And Litter-Amended Soils With Aluminum, Calcium And Iron Amendments, D. M. Miller, P. A. Moore Jr., T. C. Daniels
Phosphorus Immobilization In Poultry Litter And Litter-Amended Soils With Aluminum, Calcium And Iron Amendments, D. M. Miller, P. A. Moore Jr., T. C. Daniels
Arkansas Water Resources Center Technical Reports
Arkansas produces approximately one billion broilers each year. Phosphorous (P) runoff from fields receiving poultry litter is believed to be one of the primary factors affecting water quality in Northwest Arkansas. Poultry litter contains approximately 20 g P kg-1, of which about 2 g P kg-1 is water soluble. Soils that have received repeated heavy applications of litter may have water soluble P contents of as high as 10 mg P Kg-1 soil. The objective of this study was to determine if soluble P levels could be reduced in poultry litter and litter-amended soils with Al,Ca, and/or Fe amendments. Poultry …
Exposure Of A Food Crop To Trichloroethylene From A Contaminated Aquifer, Richard G. Baringer
Exposure Of A Food Crop To Trichloroethylene From A Contaminated Aquifer, Richard G. Baringer
Theses and Dissertations
This research developed a methodology for assessment of the exposure of a mature corn crop to trichloroethylene from a contaminated aquifer. The methodology was then applied to the case of Hill AFB to determine the ability of the methodology to provide information about a specific exposure. Current procedures sample for food contamination but do not attempt to predict exposure problems. A review of the potential exposure pathways from the aquifer to the crop was conducted. Based on this review, the exposures due to soil gas and irrigation were modeled. Empirical estimated were used to approximate the expected flux of soil …
Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp
Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp
School of Marine Science and Ocean Engineering
ABSTRACT: The potential for Light- and nutrient-limitation of phytoplankton production was examined in the Delaware Estuary, USA, by combining a hierarchy of expenmental approaches including smallscale bioassay experiments, ecosystem-level analysis of nutrient concentration and stoichiometric ratios, and light-limitation modeling. Light was found to be the predominate regulator of phytoplankton growth throughout the estuary during the winter period as a result of high turbidity and a wellmixed water column. However, during late spring, phosphorus (P) was found to limit growth. This observation was confirmed at each of the experimental levels, and was related to several factors, including elevated input ratios (230:l) …
Hydrogeology And Hydrogeochemistry Of Government Marsh, North St. Joseph County, Michigan, Michael C. Kasenow
Hydrogeology And Hydrogeochemistry Of Government Marsh, North St. Joseph County, Michigan, Michael C. Kasenow
Dissertations
A hydrogeologic and hydrogeochemical investigation was conducted at Government Marsh located in St. Joseph County, Michigan from May, 1988, to November, 1993. Information on glacial geology, topography, drainage patterns, hydraulic conductivity, vegetation, water chemistry, and static water table elevations has been collected and analyzed. Data were collected in order to determine directions of ground water flow and areas of recharge and discharge. Bail-down tests, grain-size analysis, and permeameters were used to determine hydraulic conductivity adjacent to and within the wetland. Water table elevations and chemistry were analyzed from wells adjacent to the wetland perimeter and within the boundaries of the …