The companion processes of dewatering and compaction that occur during sediment burial are strongly influenced by sediment composition and micro-fabric (i.e., grain-to-grain interactions). Improved documentation of these two processes is needed to gain better understanding of fluid flow, accretion, underplating and faulting in subduction zone settings. Drs. Tribble and Wilkens will extend earlier work from the Barbados accretionary prism to include studies of DSDP/ODP cores from Nankai Trough. X-ray diffraction will be used to determine the mineralogy of samples at several locations to develop a uniformly archived data set. Special emphasis will be placed on determining the abundances and diagenetic alteration of smectite and biogenic silica. Progressive alteration of volcanic ash to smectite will be traced. Microfabric studies will be conducted with both scanning and transmission electron microscopy, with the intention of quantifying changes in fabric with depth, composition and tectonic setting.
