301 |
Evaluation and application of the amino acid racemisation reaction in studies of quaternary coastal and marine sediments in Australia / by Colin Vincent Murray-WallaceMurray-Wallace, Colin Vincent January 1987 (has links)
Bibliography: leaves 275-290 / xviiii [i.e. xvix], 352 leaves : ill ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1987
|
302 |
Electrical resistivity methods in the unconsolidated glacial sediments of Delaware County, IndianaMay, Suzette Kimball 03 June 2011 (has links)
Delaware County, Indiana, is characterized by its glacial sediments and topography. With increasing development, the need for reliable, cost-effective subsurface surveying methods becomes more important. This thesis explores the possibilities of electrical resistivity methodology. Fifty survey sites were established on a one-mile grid over twenty square miles west of Muncie, Indiana. Three electrode arrays were tested, Wenner, Lee Partitioning, and Schlumberger, and the data interpreted by three methods, logarithmic curve matching, Moore's cumulative method, and Barnes' layer method.No one method proved to be completely accurate and reliable. Used in conjunction, however, data from the three are consistent and the techniques are viable measures for the analysis of heterogeneous glacial sediments. Additionally, apparent resistivity values which characterize the particular sediments in the study area were established and several pervasive stratigraphic units were defined.Ball State UniversityMuncie, IN 57406
|
303 |
Gas production from hydrate-bearing sediments:geo-mechanical implicationsJung, Jongwon 10 November 2010 (has links)
Gas hydrate consists of guest gas molecules encaged in water molecules. Methane is the most common guest molecule in natural hydrates. Methane hydrate forms under high fluid pressure and low temperature and is found in marine sediments or in permafrost region. Methane hydrate can be an energy resource (world reserves are estimated in 20,000 trillion m3 of CH4), contribute to global warming, or cause seafloor instability. Research documented in this thesis starts with an investigation of hydrate formation and growth in the pores, and the assessment of formation rate, tensile/adhesive strength and their impact on sediment-scale properties, including volume change during hydrate formation and dissociation. Then, emphasis is placed on identifying the advantages and limitations of different gas production strategies with emphasis on a detailed study of CH4-CO2 exchange as a unique alternative to recover CH4 gas while sequestering CO2. The research methodology combines experimental studies, particle-scale numerical simulations, and macro-scale analyses of coupled processes.
|
304 |
Carbonate diagenesis and chemical weathering in the Southeastern United States: some implications on geotechnical behaviorLarrahondo-Cruz, Joan Manuel 15 November 2011 (has links)
The Savannah River Site (SRS) deposits in the Southeastern US between 30-45 m of depth are calcium carbonate-rich, marine-skeletal, Eocene-aged sediments with varying clastic content and extensive diagenetic alteration, including meter-sized caves that coexist with brittle and hard limestone. An experimental investigation including geotechnical (P- and S-wave velocities, tensile strength, porosity) and geochemical (EDS, XRD, SEM, N2-adsorption, stable isotopes, K-Ar age dating, ICP-assisted solubility, groundwater) studies highlighted the contrast between hard and brittle limestones, their relationship with cave formation, and allowed calculation of parameters for geochemical modeling. Results demonstrate that brittle and hard limestones bear distinct geochemical signatures whereby the latter exhibits higher crystallinity, lower clastic load, and freshwater-influenced composition. Results also reveal carbonate diagenesis pathways likely driven by geologic-time seawater/freshwater cycles, microorganism-driven micritization, and freshwater micrite lithification. The second section of this investigation dealt with SRS surface soils which are largely coarse-grained and rich in iron oxides with various degrees of maturity. These soils were simulated in the laboratory using Ottawa sands that were chemically coated with goethite and hematite. Surface (SEM, AFM, N2-adsorption) and geotechnical properties (fabric, small-strain stiffness, shear strength) were investigated on the resulting "soil analog". Results indicate that iron-oxide coated sands bear distinct inherent fabric and enhanced small-strain stiffness and critical state parameters when compared to uncoated sands. Contact mechanics analyses suggest that iron oxide coatings yield an increased number of grain-to-grain contacts, higher surface roughness, and interlocking, which are believed to be responsible for the observed properties.
|
305 |
GIS analysis of the trapping efficiency of vegetative filter strips in the Bear Creek watershedMaracini, Kelly A. January 1997 (has links)
This project uses a Geographic Information System (GIS) as a tool for estimating soil erosion on a watershed scale. A new and key tool for managing ecosystems in North America are resource management plans based on watershed areas. Watershed management plans are a response to widespread concern about the cumulative effects of nonpoint source pollution (such as agriculture pollution) on water resource quality.The primary objective of this project was to develop a method using GIS to estimate the annual gross erosion for each of the watersheds. Sediment delivery was calculated within each of the subwatersheds of Bear Creek, and the amount of sediment that potentially could be trapped by vegetative filter strips in each watershed was determined. The area that was used for the study site is the Upper Bear Creek watershed. The Bear Creek watershed is a subwatershed of the Loblolly watershed in Jay County, Indiana.The analysis determined that 99% of sediment was contributed from cropland. When vegetative filter strips were modeled, the sediment delivered to a load cell was substantially reduced. Cropland area required for vegetative filter strips would be 2.3% for the whole watershed. / Department of Natural Resources and Environmental Management
|
306 |
Assessment of trace element contamination in streambed sediment and spatial associations in Palolo Valley watershed, Honolulu, Oʻahu, HawaiʻiHotton, Veronica K January 2005 (has links)
Thesis (M.A.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 146-156). / Also available by subscription via World Wide Web / xxi, 156 leaves, bound ill., maps 29 cm
|
307 |
Structural geology, metamorphism and origin of the Kanmantoo Copper deposit, South Australia / by Jeffrey Christopher Schiller.Schiller, Jeffrey Christopher January 2000 (has links)
Appendices 5 and 6 are made available in CD-ROM format. / Includes copies of articles co-authored by the author during the preparation of this thesis as appendix 7. / 14 maps (some folded, some col.); inserted in back pocket. / Includes bibliographical references (leaves 242-264). / System requirements for accompanying CD-ROM: Macintosh of IBM compatible computer. Other requirements: Adobe Acrobat Reader. / [15], 264 leaves : ill. (some col.), maps ; 30 cm. + 1 computer optical disk (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / On the basis of the present study it is concluded that there is no firm evidence that the bulk of the mineralisation is pre-metamorphic, although the possibility has not been excluded. / Thesis (Ph.D.)--Adelaide University, Dept. of Geology and Geophysics, 2001
|
308 |
The role of labile dissolved organic carbon in influencing fluxes across the sediment-water interface : from marine systems to mine lakesRead, Deborah J January 2009 (has links)
Sediment diagenesis in aquatic systems is usually understood to be controlled by the concentrations of both organic carbon and the oxidant. However, the concept that sediment respiration may be limited by the supply of organic carbon, even in systems with moderate concentrations of organic carbon in the water column, has yet to be fully explored. Typically we assume that a direct coupling between water column and sediment diagenesis processes occurs and the chemical evolution of porewater and surface water are linked through fluxes of chemical species across the sediment-water interface. While the dynamics of supply of particulate organic carbon (POC) to the sediments via plankton deposition and resuspension, has previously been examined, the fate of dissolved organic carbon (DOC) once in the sediments, has rarely been investigated. A series of experiments comprising batch tests, microcosms and sediment cores were conducted on sediment and water from four diverse field sites in which sediment respiration was considered to be carbon limited. Three sites were oligotrophic, acidic lakes and the fourth an oligotrophic coastal embayment. During each experiment dissolved organic carbon was added and measurements were undertaken of solutes that were considered participants in diagenetic processes. While each system differed in its chemical, biological and geological makeup, a key commonality was the rapid onset of anoxic conditions in the sediments irrespective of the overlying water oxygen concentrations, indicating lack of direct coupling between biogeochemical processes in the water column and sediments. Also, similar apparent DOC remineralisation rates were observed, measured solute fluxes after the addition of DOC indicated adherence to the ecological redox sequence, and increased ammonium concentrations were measured in the overlying waters of the acidic microcosms. In marine system experiments it was noted that diagenetic respiration, as indicated by decreasing concentrations of oxygen in the overlying water, increased rapidly after labile DOC was added. To explore the influence of geochemical processes on sediment respiration, a diagenetic model was tested against the laboratory data. The model was able to capture the rapid changes observed in the microcosms after addition of DOC in both the marine and acidic systems experiments. The model has the potential to serve as an essential tool for quantifying sediment organic matter decomposition and dissolved chemical fluxes. This work has focussed our attention on the control of DOC availability on sediment respiration and thus its ultimate control on solute fluxes across the sediment water interface. The results highlight the need to understand and quantify the supply of DOC to the sediment (as POC or already as the dissolved form), its transport through the sediment and its eventual remineralisation. This understanding is critical for improved management of aquatic systems, possibly even in systems where water column organic carbon is plentiful but sediment respiration is constrained by high organic carbon turnover rates in the water column and a resulting low flux of organic carbon to the sediment.
|
309 |
Structural geology, metamorphism and origin of the Kanmantoo Copper deposit, South Australia / by Jeffrey Christopher Schiller.Schiller, Jeffrey Christopher January 2000 (has links)
Appendices 5 and 6 are made available in CD-ROM format. / Includes copies of articles co-authored by the author during the preparation of this thesis as appendix 7. / 14 maps (some folded, some col.); inserted in back pocket. / Includes bibliographical references (leaves 242-264). / System requirements for accompanying CD-ROM: Macintosh of IBM compatible computer. Other requirements: Adobe Acrobat Reader. / [15], 264 leaves : ill. (some col.), maps ; 30 cm. + 1 computer optical disk (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / On the basis of the present study it is concluded that there is no firm evidence that the bulk of the mineralisation is pre-metamorphic, although the possibility has not been excluded. / Thesis (Ph.D.)--Adelaide University, Dept. of Geology and Geophysics, 2001
|
310 |
Using membrane interface probe (MIP) to characterize chlorinated volatile organic compounds in glacial sedimentsWasho, Dawn Llewellyn. January 2009 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Department of Geological Sciences, 2009. / Includes bibliographical references.
|
Page generated in 0.3515 seconds