Bibliography: p. 420-430. / In this thesis the processes that produced diamond placer deposits within closed endoreic basins along the west coast of Namibia are addressed. These deposits, first discovered in 1908, and documented by Kaiser in 1926, occur in an area of wind deflation between latitudes 26 and 28 degrees South. Salt rock weathering and aeolian abrasion has eroded elongated depressions that are up to 120 m deep, that happen to be parallel with the dominant wind flow from the south and south-southeast, which governs aeolian processes in the coastal tract. The velocity of winds from the south and south-southeast frequently averages 50 to 60 km/hour between October and March, and gusts at 80 to 90 km/hour. At these velocities, grains exceeding -1 phi (2 mm) in diameter are commonly entrained into the saltation load above stone pavement surfaces, making this an extremely active aeolian environment.

Note:

No description available.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982. / Microfiche copy available in Archives and Science / Vita. / Includes bibliographies. / by Daniel James Repeta. / Ph.D.

by Kwok Yuk Chun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 105-124). / Text in English; abstracts in English and Chinese. / by Kwok Yuk Chun. / Acknowledgements --- p.i / Abstract --- p.ii / Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xiii / List of Plates --- p.xiv / List of Appendices --- p.xv / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Hong Kong --- p.1 / Chapter 1.2 --- Sediment --- p.1 / Chapter 1.3 --- Pore water --- p.5 / Chapter 1.4 --- Toxicity identification evaluation (TIE) --- p.10 / Chapter 1.4.1 --- Phase 1: Toxicity characterization --- p.11 / Chapter 1.4.2 --- Phase 2: Toxicity identification --- p.11 / Chapter 1.4.3 --- Phase 3: Toxicity confirmation --- p.13 / Chapter 1.5 --- Bioassay --- p.15 / Chapter 1.6 --- Microtox® test --- p.16 / Chapter 2. --- OBJECTIVES --- p.18 / Chapter 3. --- MATERIALS AND METHODS --- p.19 / Chapter 3.1 --- Source of sediment samples --- p.19 / Chapter 3.2 --- Preparation of pore water --- p.19 / Chapter 3.3 --- Phase 1 Toxicity characterization: Baseline toxicity test --- p.22 / Chapter 3.3.1 --- Microtox® test --- p.22 / Chapter 3.3.2 --- Phase 1 Toxicity characterization --- p.26 / Chapter 3.3.3 --- pH adjustment test --- p.27 / Chapter 3.3.4 --- pH adjustment filtration test --- p.28 / Chapter 3.3.5 --- pH adjustment aeration test --- p.29 / Chapter 3.3.6 --- pH adjustment C18 solid phase extraction (SPE) test --- p.30 / Chapter 3.3.7 --- Cation exchange test --- p.32 / Chapter 3.3.8 --- Anion exchange test --- p.33 / Chapter 3.4 --- Phase 2 Toxicity identification --- p.34 / Chapter 3.4.1 --- Determination of metal ions by inductively coupled plasma emission spectroscopy (ICP-ES) --- p.35 / Chapter 3.4.2 --- Determination of anions by ion chromatography (IC) --- p.36 / Chapter 3.4.3 --- Determination of organic compounds by a total organic carbon (TOC) --- p.36 / Chapter 3.4.4 --- Determination of organic compounds by gas chromatography-mass spectroscopy (GC-MS) --- p.37 / Chapter 3.4.5 --- Determination of organic compounds by liquid chromatography-mass spectroscopy (LC-MS) --- p.38 / Chapter 3.4.6 --- Determination of sulphide by colorimetric method --- p.41 / Chapter 3.5 --- Phase 3 Toxicity confirmation --- p.41 / Chapter 3.5.1 --- Mass balance test --- p.44 / Chapter 3.5.2 --- Spiking test --- p.44 / Chapter 4. --- RESULTS --- p.45 / Chapter 4.1 --- General characteristics of the sediment collected in Kwun Tong Typhoon Shelter --- p.45 / Chapter 4.2 --- General characteristics of the pore water after the centrifugation of sediment --- p.45 / Chapter 4.3 --- Phase 1-Toxicity characterization: Baseline toxicity test --- p.45 / Chapter 4.4 --- Phase 1-Toxicity characterization --- p.48 / Chapter 4.4.1 --- Effect of manipulations on Sample S1 --- p.48 / Chapter 4.4.2 --- Effect of manipulations on Sample S2 --- p.50 / Chapter 4.4.3 --- Effect of manipulations on Sample S3 --- p.50 / Chapter 4.4.4 --- Effect of manipulations on Sample S4 --- p.52 / Chapter 4.4.5 --- Effect of manipulations on Sample S5 --- p.55 / Chapter 4.4.6 --- Effect of manipulations on Sample S6 --- p.57 / Chapter 4.4.7 --- Summary of the Phase 1 manipulations on the Microtox® test --- p.59 / Chapter 4.5 --- Phase 2-Toxicity identification --- p.59 / Chapter 4.5.1 --- Summary of the Phase 2 toxicity identification --- p.70 / Chapter 4.6 --- Phase 3-Toxicity confirmation --- p.70 / Chapter 4.6.1 --- Result of Phase 3 for Sample S3 --- p.70 / Chapter 4.6.2 --- Result of Phase 3 for Sample S4 --- p.73 / Chapter 4.6.3 --- Result of Phase 3 for Sample S5 --- p.76 / Chapter 4.6.4 --- Result of Phase 3 for Sample S6 --- p.79 / Chapter 4.6.5 --- Summary of the Phase 3 toxicity confirmation --- p.79 / Chapter 5. --- DISCUSSION --- p.82 / Chapter 5.1 --- Phase 1 Toxicity characterization: Baseline toxicity test --- p.82 / Chapter 5.1.1 --- Baseline toxicity of whole pore water samples on the Microtox® test --- p.82 / Chapter 5.2 --- Phase 1-Toxicity characterization: Manipulations --- p.83 / Chapter 5.2.1 --- Effect of manipulations on the Microtox® test --- p.83 / Chapter 5.2.2 --- pH adjustment test --- p.83 / Chapter 5.2.3 --- pH adjustment filtration test --- p.84 / Chapter 5.2.4 --- pH adjustment aeration test --- p.85 / Chapter 5.2.5 --- Cation exchange test --- p.85 / Chapter 5.2.6 --- Anion exchange test --- p.86 / Chapter 5.2.7 --- pH adjustment C18 solid phase extraction (SPE) test --- p.86 / Chapter 5.3 --- Phase 2-Toxicity identification --- p.87 / Chapter 5.4 --- Phase 3-Toxicity confirmation --- p.88 / Chapter 5.4.1 --- Mass balance on the Microtox® test --- p.89 / Chapter 5.4.2 --- Spiking test on the Microtox® test --- p.90 / Chapter 5.5 --- Explanation of S as the major toxicant in Phase 1，Phase 2 and Phase3 --- p.90 / Chapter 5.6 --- Characteristics of Sulphide (S2-) --- p.91 / Chapter 5.6.1 --- Sources of S2- --- p.91 / Chapter 5.6.2 --- Harmful effect of S “ and its toxicity --- p.93 / Chapter 5.6.3 --- Sulphide determination by colorimetric method --- p.94 / Chapter 5.6.4 --- Sulphide determination by other methods --- p.95 / Chapter 5.6.5 --- Sulphide preservation --- p.95 / Chapter 5.7 --- Synergistic effect of S2- and C18 SPE test elutriate --- p.96 / Chapter 5.8 --- Treatment of contaminated marine sediment in Hong Kong --- p.97 / Chapter 5.9 --- Treatment of contaminated marine sediment in Kwun Tong Typhoon Shelter --- p.98 / Chapter 5.10 --- Treatment of sediment contaminated with sulphide in Hong Kong --- p.99 / Chapter 5.11 --- Other treatment method of sediment contaminated with sulphide --- p.100 / Chapter 5.12 --- Current limitations and abilities in identification of toxicants in pore water --- p.101 / Chapter 5.13 --- Improvement and Recommendations --- p.102 / Chapter 6. --- CONCLUSIONS --- p.104 / Chapter 7. --- REFERENCES --- p.105 / Chapter 8. --- APPENDICES --- p.125

No description available.

Gas hydrates are crystalline compounds made of gas and water molecules. Methane hydrates are found in marine sediments and permafrost regions; extensive amounts of methane are trapped in the form of hydrates. The unique behavior of hydrate-bearing sediments requires the development of special research tools, including new numerical algorithms (tube- and pore-network models) and experimental devices (high pressure chambers and micromodels). Hydraulic conductivity decreases with increasing variance in pore size distribution; while spatial correlation in pore size reduces this trend, both variability and spatial correlation promote flow focusing. Invading gas forms a percolating path while nucleating gas forms isolated gas bubbles; as a result, relative gas conductivity is lower for gas nucleation than for gas invasion processes, and constitutive models must be properly adapted for reservoir simulations. Physical properties such as gas solubility, salinity, pore size, and mixed gas conditions affect hydrate formation and dissociation; implications include oscillatory transient hydrate formation, dissolution within the hydrate stability field, initial hydrate lens formation, and phase boundary changes in real field situations. High initial hydrate saturation and high depressurization favor gas recovery efficiency during gas production from hydrate-bearing sediments. Even a small fraction of fines in otherwise clean sand sediments can cause fines migration and concentration, vuggy structure formation, and gas-driven fracture formation during gas production by depressurization.

Graduation date: 1980

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aims of this investigation on the Holocene carbonate successions of three shallow, ephemeral lakes from the Cooring coastal plain were: to determine the timing of the sapropel ’events’ in the three lakes; to determine the origin of the sapropelic organic matter and evaluate changes; to establish whether sapropel deposition in these shallow, coastal lakes primarily reflects increased organic matter delivery to the sediments during periods of enhanced terrestrial input and/or aquatic productivity, and; to relate sapropel deposition in these three lakes to both regional and global palaeoenvironment reconstructions. --p. 23-24. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1324064 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aims of this investigation on the Holocene carbonate successions of three shallow, ephemeral lakes from the Cooring coastal plain were: to determine the timing of the sapropel ’events’ in the three lakes; to determine the origin of the sapropelic organic matter and evaluate changes; to establish whether sapropel deposition in these shallow, coastal lakes primarily reflects increased organic matter delivery to the sediments during periods of enhanced terrestrial input and/or aquatic productivity, and; to relate sapropel deposition in these three lakes to both regional and global palaeoenvironment reconstructions. --p. 23-24. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1324064 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007