Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- Western Michigan University (19480)
- University of Kentucky (10978)
- University of Nebraska - Lincoln (4538)
- University of South Florida (1871)
- China Coal Technology and Engineering Group (CCTEG) (1799)
-
- Department of Primary Industries and Regional Development, Western Australia (1669)
- Utah State University (1564)
- TÜBİTAK (917)
- Missouri University of Science and Technology (775)
- University of Arkansas, Fayetteville (760)
- Boise State University (667)
- Portland State University (665)
- Old Dominion University (661)
- University of Nevada, Las Vegas (521)
- University of Texas Rio Grande Valley (517)
- Montana Tech Library (496)
- Western Kentucky University (496)
- University of Colorado Law School (481)
- University of North Dakota (448)
- Louisiana State University (423)
- University of New Mexico (401)
- Montclair State University (383)
- Central Washington University (368)
- University of Texas at El Paso (316)
- City University of New York (CUNY) (314)
- University of South Carolina (275)
- Michigan Technological University (253)
- Brigham Young University (240)
- University of Texas at Arlington (237)
- University of New Hampshire (229)
- Keyword
-
- Western Australia (1183)
- Geology (901)
- Grains and field crops (625)
- Groundwater (619)
- Nebraska (589)
-
- Climate change (461)
- Grazing (407)
- Geochemistry (403)
- Soil (372)
- Hydrology (358)
- Montana (326)
- Nitrogen (323)
- Kentucky (302)
- Remote sensing (282)
- Salinity (282)
- Water quality (280)
- Drought (277)
- Utah (272)
- Water (240)
- Karst (233)
- Alfalfa (223)
- Climate (219)
- Geophysics (216)
- Hydrogeology (214)
- Phosphorus (213)
- Agriculture (203)
- Geomorphology (203)
- Stratigraphy (203)
- Irrigation (202)
- United States (191)
- Publication Year
- Publication
-
- Legacy Scout Tickets from Pure Oil Company (11044)
- IGC Proceedings (1977-2023) (9261)
- Thin Sections (6677)
- Coal Geology & Exploration (1799)
- Legacy Color Lithology Strip Logs (1152)
-
- United States Geological Survey: Staff Publications (1026)
- Turkish Journal of Earth Sciences (917)
- Conservation and Survey Division: Faculty and Staff Publications (901)
- International Journal of Speleology (888)
- Theses and Dissertations (826)
- Department of Earth and Atmospheric Sciences: Faculty Publications (670)
- Experimental Summaries - Plant Research (668)
- Masters Theses (591)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (454)
- School of Earth, Environmental, & Marine Sciences Faculty Publications (426)
- Bachelors Theses and Reports, 1928 - 1970 (423)
- Faculty Publications (407)
- Geosciences Faculty Publications and Presentations (392)
- Kentucky Alfalfa and Stored Forage Conference (382)
- School of Geosciences Faculty and Staff Publications (355)
- Earth and Planetary Sciences ETDs (343)
- Dissertations and Theses (342)
- Graduate Theses and Dissertations (338)
- Electronic Theses and Dissertations (326)
- Memorandum (316)
- Resource management technical reports (315)
- Open Access Theses & Dissertations (295)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (279)
- USF Tampa Graduate Theses and Dissertations (264)
- Department of Earth and Environmental Studies Faculty Scholarship and Creative Works (262)
- Publication Type
Articles 53131 - 53160 of 59392
Full-Text Articles in Entire DC Network
Resource News-July/August 1992
Resource News-July/August 1992
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Mineral Resource Map Of Nebraska, R. R. Burchett
Mineral Resource Map Of Nebraska, R. R. Burchett
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Geologic Bedrock Map Of Nebraska, R. R. Burchett
Geologic Bedrock Map Of Nebraska, R. R. Burchett
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Description Of Rocks From A Core Drilled At A Potential Low-Low Level Radioactive Waste Site In Nemaha County, R. R. Burchett
Description Of Rocks From A Core Drilled At A Potential Low-Low Level Radioactive Waste Site In Nemaha County, R. R. Burchett
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
United States Geological Survey Bridge Scour Evaluation Program In Texas, David D. Dunn, Henry R. Hejl Jr.
United States Geological Survey Bridge Scour Evaluation Program In Texas, David D. Dunn, Henry R. Hejl Jr.
United States Geological Survey: Staff Publications
The Federal Highway Administration has mandated that all bridges in the Federal Aid System crossing over water be evaluated for scour susceptibility. The United States Geological Survey and the Texas Department of Transportation (TXDOT) have initiated a multi-year, multi-phase program to develop scour evaluation and analysis procedures that will allow TXDOT to quickly and efficiently evaluate some 11,000 bridges crossing over water in the state.
Usgs Urban Stonnwater Investigations In The Dallas-Fort Worth, Texas Metroplex, R. Brad Jennings, Tim H. Raines, Lucia G. Colangione
Usgs Urban Stonnwater Investigations In The Dallas-Fort Worth, Texas Metroplex, R. Brad Jennings, Tim H. Raines, Lucia G. Colangione
United States Geological Survey: Staff Publications
Stormwater runoff in urban and industrialized areas carries a considerable amount of pollutants to nearby lakes and streams. In an effort to control this source of pollution, the U.S. Environmental Protection Agency has issued stormwater regulations to control these discharges. Municipalities with a population of 100,000 or more must undertake a process to obtain permits to control the quality of their storm runoff. The Dallas-Fort Worth metroplex includes seven cities that must meet these regulations and obtain permits. The U.S. Geological Survey is assisting the North Texas Council of Governments and its associated cities in meeting the water science requirements …
Numerical Methods 101 - Convergence Of Numerical Models, David B. Thompson
Numerical Methods 101 - Convergence Of Numerical Models, David B. Thompson
United States Geological Survey: Staff Publications
A numerical model is convergent if and only if a sequence of model solutions with increasingly refined solution domains approaches a fixed value. Furthermore, a numerical model is consistent only if this sequence converges to the solution of the continuous equations which govern the physical phenomenon being modeled. Given that a model is consistent, it is insufficient to apply it to a problem without testing for sensitivity to the size of the time and distance steps which form the discrete approximation of the solution domain. That is, convergence testing is a required component of any modeling study.
Two models were …
Flux Of Metals Between Sediment And The Water Column, N. S. Simon, K. O. Dennen
Flux Of Metals Between Sediment And The Water Column, N. S. Simon, K. O. Dennen
United States Geological Survey: Staff Publications
The role of nitrogen-containing compounds in the flux of metals between sediment and the overlying water column is discussed.
Stress-Strain Relation In Debris Flow Analysis, Chi-Hai Ling, Cheng-Lung Chen, Chyan-Deng Jan
Stress-Strain Relation In Debris Flow Analysis, Chi-Hai Ling, Cheng-Lung Chen, Chyan-Deng Jan
United States Geological Survey: Staff Publications
In debris flow analysis, the generalized viscop1astic fluid (GVF) model can be used as the constitutive equations. When the yield stress is negligible, the shear expression in the GVF model for simple shear flow reduces to r = µ1 (du/dz)n, where r is the shear stress, µ1 is the consistency index, du/dz is the shear rate, and n is the flow behavior index. In this paper the r versus du/dz relation is studied by running experiments with 14 mm dry glass spheres in a conveyor-belt flume. A comparison of the estimated r with the measured du/dz …
Topographic Effects On Stormflow Acidity, David Wolock
Topographic Effects On Stormflow Acidity, David Wolock
United States Geological Survey: Staff Publications
This paper describes the theoretical and observed effects of topography on stormflow acidity in upland, forested watersheds. The theoretical effects were determined by a sensitivity analysis using the hydrologic model TOPMODEL. The observed effects were determined by an analysis of topographic and stormflow acidity data collected from eight watersheds in Wales, Great Britain. Results of the analyses indicated that the observed effects of topography were consistent with the theoretical expectations; that is, topography has an important effect on flow path, and that flow path, in turn, has an effect on stormflow acidity.
Network Applications Of The Usgs Branch Model, Raymond W. Schaffranek
Network Applications Of The Usgs Branch Model, Raymond W. Schaffranek
United States Geological Survey: Staff Publications
Applications of a numerical model for simulating unsteady flow in dendritic or interconnected open-channel networks are presented to demonstrate the model's potential for addressing environmental problems and formulating engineering decisions in water-resources investigations. The model is computationally robust and readily adaptable to a broad spectrum of hydraulic conditions and open-channel configurations. The four-point, implicit, finite difference model has been implemented on numerous open-channel reaches and networks in support of various water-resources investigations conducted within the U.S. Geological Survey. In this paper, network applications of the model to a residential canal system in Cape Coral, Florida; to a distributary system of …
Modeling Flow And Flood-Plain Storage In A Tidally Affected River, A. G. Strickland, Jerad D. Bales
Modeling Flow And Flood-Plain Storage In A Tidally Affected River, A. G. Strickland, Jerad D. Bales
United States Geological Survey: Staff Publications
A one-dimensional, unsteady-flow model was calibrated, validated, and tested for a 30.4-mile reach of the tidally affected Roanoke River, North Carolina. The model includes a storage reservoir to represent the two-dimensional processes associated with flood-plain storage and release in the one-dimensional flow model. Simulated and measured water levels differed by less than 0.5 foot, and the average absolute difference between simulated and measured flows was 7 percent.
Incorporating Hydraulic Structures In An Open-Channel Model, Eric D. Swain
Incorporating Hydraulic Structures In An Open-Channel Model, Eric D. Swain
United States Geological Survey: Staff Publications
The open-channel flow model, BRANCH, is a routinely used numerical tool for modeling rivers, canals, and waterway networks. Although a simplified hydraulic structure representation is included in the model, no universal subroutine that can represent hydraulic structures by their rating curve equations has been included in the BRANCH model.
Accordingly, a subroutine has been developed that specifies flow through a structure by a stage-discharge relation. The structure flow equation is used to generate coefficients in the solution matrix that represent the structure in the same computational format as the open-channel flow equations. Field applications have shown that this new subroutine …
8. Cretaceous Subtropical Weathering Followed By Cooling At 60°S Latitude: The Mineral Composition Of Southern Kerguelen Plateau Sediment, Leg 120, Mary Anne Holmes
8. Cretaceous Subtropical Weathering Followed By Cooling At 60°S Latitude: The Mineral Composition Of Southern Kerguelen Plateau Sediment, Leg 120, Mary Anne Holmes
Department of Earth and Atmospheric Sciences: Faculty Publications
Kaolinite, goethite, minor hematite, and gibbsite were found in fluvial upper Lower Cretaceous basal sediment from the Southern Kerguelen Plateau, Sites 748 and 750, 55°S latitude. This mineral assemblage, derived from the weathering of basalt, indicates near-tropical weathering conditions with high orographic rainfall, at least 100 cm per year. The climate deteriorated by the Turonian or Coniacian, as indicated by the decline in kaolinite content of this sediment.
The Upper Cretaceous sediment at Site 748 consists of 200 m of millimeter-laminated, sparsely fossiliferous, wood-bearing glauconitic siltstone and clay stone with siderite concretions deposited on a shelf below wave base. Some …
9. Composition And Origin Of Cr-Rich Glauconitic Sediments From The Southern Kerguelen Plateus (Site 748), Peter Rene Bitschene, Mary Anne Holmes, James Brezza
9. Composition And Origin Of Cr-Rich Glauconitic Sediments From The Southern Kerguelen Plateus (Site 748), Peter Rene Bitschene, Mary Anne Holmes, James Brezza
Department of Earth and Atmospheric Sciences: Faculty Publications
Five hundred meters of a unique Upper Cretaceous Cr-rich glauconitic sequence (Unit III) that overlies a 3-m-thick alkali-basalt flow with underlying epiclastic volcanogenic sediments was drilled at ODP Leg 120 Site 748. The Cr-rich glauconitic sequence is lithostratigraphically and biostratigraphically divided into three subunits (IIIA, IIIB, IIIC) that can also be recognized by the Cr concentration of the bulk sediment, which is low (<200 ppm) in Subunits IIIC and IIIA and high (400-800 ppm) in Subunit IIIB. The Cr enrichment is caused by Cr-spinel, which is the only significant heavy mineral component beside Fe-Ti ores. Other Cr-bearing components are glauconite pellets and possibly some other clay minerals.
The glauconitic sequence of Subunit IIIB was formed by reworking of glauconite and volcanogenic components that were transported restricted distances and redeposited downslope by mass-transportation processes. The site of formation was a nearshore, shallow inner shelf …200>
Superambient Heat Capacities Of Synthetic Stibnite, Berthierite, And Chalcostibite: Revised Thermodynamic Properties And Implications For Phase Equilibria, Robert R. Seal Ii, Richard A. Robie, Paul B. Barton Jr., Bruce Hemingway
Superambient Heat Capacities Of Synthetic Stibnite, Berthierite, And Chalcostibite: Revised Thermodynamic Properties And Implications For Phase Equilibria, Robert R. Seal Ii, Richard A. Robie, Paul B. Barton Jr., Bruce Hemingway
United States Geological Survey: Staff Publications
Stibnite (Sb2S3), berthierite (FeSb2S4), and chalcostibite (CuSbS2) are important antimony-bearing minerals. Stibnite is the main ore mineral of antimony and occurs as an important accessory in many epigenetic ore deposits, especially in later stages of deposition or in peripheral facies of mineralization. Berthierite is a common accessory mineral in antimony deposits. Its occurrence, particularly in gold-antimony deposits, has received considerable scientific attention. Furthermore, stibnite, berthierite, and chalcostibite represent important reference phases for understanding phase equilibria in more complex systems, such as those containing tetrahedrite-tennantite solid solutions.
Stable Isotope Study Of Water-Rock Interaction And Ore Formation, Bayhorse Base And Precious Metal District, Idaho, Robert R. Seal Ii, Robert O. Rye
Stable Isotope Study Of Water-Rock Interaction And Ore Formation, Bayhorse Base And Precious Metal District, Idaho, Robert R. Seal Ii, Robert O. Rye
United States Geological Survey: Staff Publications
The Bayhorse base and precious metal district situated east of the Idaho batholiths in south-central Idaho. The ores occur near the Nevada Mountain granitic stock as veins cutting the lower Paleozoic Ramshorn Slate and the Garden Creek Phyllite, and as fillings around breccias fragments within the Bayhorse Dolomite. The veins are dominated by siderite and tetrahedrite, with lesser quartz and galena, whereas the breccias ores dominantly comprise only quartz and galena. Mineralization and intrusive activity were contemporaneous during Cretaceous time. Fluid inclusion and stable isotope data indicate that mineralization formed from hot (ca. 375° -225°C), CO2-rich (≤8.3 ± …
Introduction To Special Section On The Cajon Pass Scientific Drilling Project, Mark D. Zoback, Arthur H. Lachenbruch
Introduction To Special Section On The Cajon Pass Scientific Drilling Project, Mark D. Zoback, Arthur H. Lachenbruch
United States Geological Survey: Staff Publications
Over the past few decades a generally accepted conceptual model for the thermomechanics of the San Andreas fault was based on three factors believed to have been supported by observation: (1) maximum horizontal shear stress increases with depth in the crust at the rate of 7-8 MPa/km (as indicated by measurements in relatively shallow boreholes), roughly the same rate of shear stress increase as in other regions [e.g., McGarr et al., 1982], (2) the maximum horizontal stress direction in the vicinity of the fault was oriented at about 300-45 ° to its strike (as indicated by the predominance of right-lateral …
Sr-Isotope Record Of Quaternary Marine Terraces On The California Coast And Off Hawaii, Kenneth R. Ludwig, Daniel R. Muhs, Kathleen R. Simmons, James G. Moore
Sr-Isotope Record Of Quaternary Marine Terraces On The California Coast And Off Hawaii, Kenneth R. Ludwig, Daniel R. Muhs, Kathleen R. Simmons, James G. Moore
United States Geological Survey: Staff Publications
Strontium-isotopic ratios of dated corals have been obtained from submerged reefs formed during Quaternary glacial periods off the Hawaiian islands. These data, combined with data from deep-sea sediments, tightly constrain the secular variation of marine 87Sr/86Sr for the past 800,000 yr. Although long-term trends are apparent, no significant (>0.02‰), rapid (<100,000 yr) excursions in 87Sr/86Sr were resolved nor did we observe any samples with 87Sr/86Sr greater than that of modern seawater. Strontium in mollusks from elevated marine terraces formed during interglacial periods on the southern California coast show resolvable and consistent variations in …100,000>
Hydrogeologic Characterization Of A Discharge Wetland In Northeastern Grand Forks County, North Dakota, Dean R. Goebel
Hydrogeologic Characterization Of A Discharge Wetland In Northeastern Grand Forks County, North Dakota, Dean R. Goebel
Theses and Dissertations
Soil salinization associated with saline groundwater discharge results in decreased agricultural production in the central glacial Lake Agassiz plain of North Dakota. Saline discharge occurs in a belt of ephemeral wetlands in the lake plain. The physical and chemical hydrology of .the Lunby-stewart saline discharge wetland were investigated in order to provide information which could facilitate land management strategies applicable to this and other discharge wetlands.
Hydrologic data used to characterize the wetland were obtained from monitoring wells, staff gages, precipitation gages, borings, and earth electrical resistivity soundings. Temporal and spatial variations were observed in the water table, the vertical …
The First Documentation Of A Lower Middle Pennsylvanian Upland Flora From The Eastern Margin Of The Eastern Interior Basin (Illinois Basin), Vicki J. Comer
The First Documentation Of A Lower Middle Pennsylvanian Upland Flora From The Eastern Margin Of The Eastern Interior Basin (Illinois Basin), Vicki J. Comer
Masters Theses
The primary objective of this study is to reconstruct the paleofloristics of an unnamed shale of lower Middle Pennsylvanian age. The shale is periodically exposed in the highwall of the Ashboro Pit, Log Cabin Coal Company, Clay County, Indiana. This will be the first upland fossil flora to be described from the eastern margin of the Eastern Interior Basin (Illinois Basin). The gray shale containing the upland flora lies directly above the Upper Block Coal (SW 1/4, SE 1/4, sec. 17, T. 11N., R. 6W.)
Two collections, collected on three different occasions were made available for analysis: Smithsonian Natural …
Morphometric Analysis Of Dolines, A. Bondesan, M. Meneghel, U. Sauro
Morphometric Analysis Of Dolines, A. Bondesan, M. Meneghel, U. Sauro
International Journal of Speleology
The doline is the most specific surface form of karst landscapes, which enables one to distinguish them from “normal” erosion landscapes shaped by surface water. From a morphodynamic point of view the doline constitutes an elementary hydrographic unit, comparable to a simple basin, which, with its system of slopes, conveys water to the absorbing points at the bottom into an underground network. The morphometric study of these karst landforms enables a quantitative analysis of karst environment. Comparisons of the various parameters may give unexpected results and lead to new hypotheses about the evolution and the dynamism of the karst “geo-ecosystem”. …
Distribution Of Foraminifera And Pollen In Coastal Depositional Environments Of The Southern Delmarva Peninsula, Virginia, U.S.A., Han Jun Woo
OES Theses and Dissertations
The coastal zone of the southern Delmarva Peninsula exhibits a wide variety of barrier island system subenvironments. This study investigates whether 20 a priori subenvironments can be distinguished from each other on the basis of abiotic environmental variables, pollen assemblages, living foraminiferal populations, and total (living plus dead) foraminiferal assemblages.
The physical data collected from the coastal zone were subjected to canonical variate analysis which discriminated 83% of the stations in 19 groups. These groups were clustered into two internally overlapping sets which represented the inside and outside of the inlet.
Twenty-two pollen types were found in low-energy marsh and …
Remote Estimation Of The Diffuse Attenuation Coefficient In A Moderately Turbid Estuary, Richard P. Stumpf, Jonathan Pennock
Remote Estimation Of The Diffuse Attenuation Coefficient In A Moderately Turbid Estuary, Richard P. Stumpf, Jonathan Pennock
School of Marine Science and Ocean Engineering
Abstract
Solutions of the radiative transfer equation are used to derive relationships of water reflectance to the diffuse attenuation coefficient (K) in moderately turbid water (K > 0.5 m−1). Data sets collected from the NOAA AVHRR and in situ observations from five different dates confirm the appropriateness of these relationships, in particular the logistic equation. Values of K calculated from the reflectance data agree to within 60% of the observed values, although the reflectance derived using a more comprehensive aerosol correction is sensitive to chlorophyll concentrations greater than 50 μg L−1. Agreement between in situ and remote …Soil Surveys And Related Investigations In The Ord River Area, East Kimberley, 1944, George Henry Burvill
Soil Surveys And Related Investigations In The Ord River Area, East Kimberley, 1944, George Henry Burvill
Technical Bulletins
No abstract provided.
Geology Newsletter- 1991, Department Of Geology
Geology Newsletter- 1991, Department Of Geology
Geological and Environmental Sciences News
Vol.1, No. 16
- Core Research Lab
- Faculty News
- Service Staff News
- Alumni/ Friends/ Former Faculty Notes
- 1991 Speakers Program
- New Alumni
- Awards and Scholarships
- Geology Club
Ecological Aspects Of Burrowing Owl Nesting Strategies In The Nebraska Panhandle, Martha J. Desmond
Ecological Aspects Of Burrowing Owl Nesting Strategies In The Nebraska Panhandle, Martha J. Desmond
School of Natural Resources: Dissertations, Theses, and Student Research
No abstract provided.
Bird Response To Monofilament Lines At Backyard Feeders, Kimberly K. Kessler
Bird Response To Monofilament Lines At Backyard Feeders, Kimberly K. Kessler
School of Natural Resources: Dissertations, Theses, and Student Research
No abstract provided.
Groundwater Levels In Nebraska, 1990, Gregory V. Steele, Perry B. Wigley
Groundwater Levels In Nebraska, 1990, Gregory V. Steele, Perry B. Wigley
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Environmental Radiocesium In Subarctic And Arctic Alaska Following Chernobyl, M. Baskaran, J. J. Kelley, A. S. Naidu, D. F. Holleman
Environmental Radiocesium In Subarctic And Arctic Alaska Following Chernobyl, M. Baskaran, J. J. Kelley, A. S. Naidu, D. F. Holleman
Environmental Science and Geology Faculty Research Publications
Radiocesium (¹³⁴ Cs and ¹³⁷ Cs) concentrations were measured in soil, plant and wildlife samples from subarctic to arctic Alaska. Concentrations of ¹³⁷ Cs ranged from below detectable or low levels in whale and fish samples to as high as 242 Bq/kg in lichen. For all potential human food items, the radiocesium concentrations measured in this study were below accepted permissible levels for human consumption. Chernobyl-derived radiocesium concentrations ranged from below detectable or low levels in all arctic samples (soil, sediment, lichen, whale, fish and caribou) to 32 Bq/kg in subarctic moss. Therefore the distribution and subsequent deposition of Chernobyl-derived …