Organic geochemistry, visual composition, atomic ratios, and reflectance at DSDP Site 87-582, 87-583 and 87-584

Geochemical analyses of organic matter were carried out on Quaternary sediments from Sites 582 and 583 (Nankai Trough) and on Pliocene to Miocene sediments from Site 584 (Japan Trench), DSDP Leg 87, to evaluate petroleum-generating potential and to characterize the organic matter. The vitrinite-huminite reflectances of indigenous materials for these sites are less than 0.3% indicating the immature nature of the sediments. The sediments, however, contain remarkable amounts of recycled organic materials. The Quaternary sediments from Sites 582 and 583 contain small amounts of amorphous organic matter (less than 0.75 wt.% organic carbon and 66-90% amorphous debris), which is composed of predominantly recycled, oxidized, and over-matured (or matured) Type III material. The amount of hydrocarbon yield indicates that those sediments have lean-source potential for commercial hydrocarbon generation. The Pliocene to Miocene sediments from Site 584 contain organic matter (0.3-1.09 wt.% organic carbon) of predominantly amorphous debris (68-96%) that originated in two sources, an indigenous Type II material and a recycled, over-matured material. Pyrolysis shows an upward increase in the section of hydrocarbon yield and the same trend is also observed in organic-carbon content. The amount of the yield indicates that the Miocene sediments have lean-to-fair source potential and the Pliocene sediments have fair-to-good source potential.

Swath sonar bathymetry during SONNE cruise SO196 with links to multibeam raw data files

Multibeam data were measured during R/V Sonne cruise SO-196 (2008-03-02 to 2008-03-27) along survey profiles, transits and during stationary work. Data were achieved at the Okiwana Trough, particularly in the area of Yonaguni Knoll and Hatoma Knoll. The multibeam sonar system Kongsberg EM120 was operated using 191 beams and up to 150 deg aperture angle. The refraction correction was achieved using CTD profiles measured during this cruise. The quality of data might be reduced during bad weather periods. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.