P175-TU INVESTIGATION OF GEM-ALKANES IN SURFACE SEDIMENTS FROM THREE METHANE-SEEP SEA

• Main Authors: Areas Off Japan, Shigenori Ogihara, Yifeng Chen, Ryo Matsumoto, Juichiro Ashi
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Methane hydrate
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.505.2287; http://www.imog2007.org/files/Tuesday Posters/Tuesday Posters Microbial Geochemistry/P175-TU Ogihara.pdf

Mud samples collected from three methane-seep sites in the sea around Japan were analysed. All samples contain a small amount of pentamethylicosane (PMI) that characterizes anoxic oxidation of methane (AOM). The feature of the three samples is that they contain several kinds of gem-alkanes. These are the predominant biomarker compounds in the samples analysed in this study. The composition of these biomarkers is different from the known features of the methane-seep sites. Samples (1) Surface sediment on top of a mud volcano in the Nankai Trough: Nankai Trough is the subduction margin between the Philippine Sea Plate and the Eurasia Plate. The current accretionary prism is building out from the trench and is increasing in thickness landward. The Kumano forearc basin is located east of the Kii Peninsula and is the forearc basin of the Nankai Trough. The 2002 “DAISINKAI ” project investigated the Kumano basin for methane hydrate. KP-2 is the piston core collected from the top of one of the mud volcano in the Kumano basin, and the water depth was 1930 m. (2) Surface sediment covered by a bacterial mat with cold seep in the Ryuyo Canyon: In the eastern Nankai Trough, the accretionary prism formed by offscraping of incoming sediments from the Philippine Sea