Japan Geoscience Union Meeting 2015

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS24] Gas hydrates in environmental-resource sciences

Wed. May 27, 2015 4:15 PM - 6:00 PM 101B (1F)

Convener:*Hitoshi Tomaru(Department of Earth Sciences, Chiba University), Akihiro Hachikubo(Environmental and Energy Resources Research Center, Kitami Institute of Technology), Sumito Morita(Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology), Chair:Hitoshi Tomaru(Department of Earth Sciences, Chiba University)

5:36 PM - 5:39 PM

[MIS24-P08] Paleoenvironmental change elucidated from the total organic carbon concentration and stable isotope from Mogami trough

3-min talk in an oral session

*Tasuku URABE1, Fujio KUMON2 (1.Faculty of Science, Shinshu university, 2.Department of Environmental Sciences, Faculty of Science, Shinshu University)

Keywords:Paleoenvironmental change, Quaternary, Japan sea, organic carbon, stable isotope

The temporal changes in total organic carbon (TOC) concentration for cored sediment off Joetsu city, Japan Sea is very similar to the millennial scale climate change at the northern hemisphere (Urabe et al., 2014). Then, we analyzed the TOC, total nitrogen (TN) concentration and these stable isotope ratio δ13C and δ15N values with high temporal resolution for new core RC1408 from Mogami trough, Japan Sea. TOC concentration and δ13C value for RC1408 is high during Holocene, and low in Last glacial maxima (LGM).
The high TOC concentration during middle to late Holocene suggests high biological productivity in the sea surface. The contribution of marine organic matter to TOC was increasing with sea level rising, suggesting the decreasing trend of C/N ratio and increasing trend of δ13C value during 6.0~9.8 ka, and then becoming current oceanological condition at 6.0 ca. In the last deglaciation, the rapid increasing TOC concentration and δ13C value suggest increasing marine biological productivity. In the last glacial maxima, the marine biological productivity was very low and the contribution of terrestrial organic matter increased but the inflow was very little, according to the lowest TOC concentration and δ13C value.This study is a part of a develooment methane hydrate project, Ministry of Economy, Trade and Industry.