Influence of Chemical, Physical, Biological and Geochemical Processes of EarlyDiagenesis and Material Exchange Across the Sediment/Seawater Interface in Margin Sediments

摘要

Long-Term Goals and Summary of Accomplishments: The goals of this project were todetermine links between sediment chemistry, physical properties, and microfabric during the early diagenesis of surface and near-surface, organic-rich sediments. To this end, we provided high resolution characterizations of sediment microfabric, physical properties, chemistry, mineralogy, and organic matter content as well as theoretical work on smectite interlayer hydration. The data collected were used to permit observation of organic matter as it occurs in natural sediments, determine the mechanism for the preservation of organic matter in continental margins and the important role clay minerals play in this regard, to evaluate the impact of the oxygen minimum zone on organic matter abundance and regeneration, and to demonstrate the significant impact organic matter has on sediment physical properties. Mathematical relations were also developed to permit the partitioning of 1120 between hydrous mineral phases in the sediment and intergranular porosity and sediment void ratio and preliminary studies were carried out to examine the potential of the stable isotopes of chlorine for fingerprinting sediment pore waters. In addition, statistical data were accumulated that indicate the range of variability of geotechincal properties on millimeter, centimeter, and kilometer scales for undissected portions of the western North American continental slope.