Japan Geoscience Union Meeting 2015

Presentation information


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

[M-IS34] Paleoclimatology and paleoceanography

Thu. May 28, 2015 4:15 PM - 6:00 PM 301A (3F)

Convener:*Kazuyoshi Yamada(Museum of Natural and Environmental history, Shizuoka), Minoru Ikehara(Center for Advanced Marine Core Research, Kochi University), Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Ikuko Kitaba(Research Centre for Palaleoclimatology, Ritsumeikan University), Akihisa Kitamura(Institute of Geosciences, Faculty of Science, Shizuoka University), Masaki Sano(Research Institute for Humanity and Nature), Takeshi Nakagawa(Ritsumeikan University), Akira Hayashida(Department of Environmental Systems Science, Doshisha University), Chair:Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University)

5:45 PM - 6:00 PM

[MIS34-23] Reconstruction of Andaman Sea coastal environment during the past 500 years

*Yuki OTA1, Hodaka KAWAHATA1, Yusuke YOKOYAMA2, Masafumi MURAYAMA3, Mayuri INOUE4, Yousuke MIYAIRI2 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.Atmosphere and Ocean Research Institute, University of Tokyo, 3.Center for Advanced Marine Core Research , Kochi University, 4.Department of Earth Sciences, Okayama University)

Keywords:sedimentary condition, Andaman Sea, grain size analysis

The Andaman Sea is a semi enclosed marginal sea in the northern Indian Ocean. Marine sediment of Andaman Sea is supplied not only from Ayeyawady‐Salween river system but also from surface current from the Bay of Bengal driven by Indian monsoon. Although the change of coastal sediment environment in Andaman Sea is important for understanding climate system associated with livelihood, their reconstruction remains unclear. In this study, a marine sedimentary record sampled at a water depth of 75 m (core length: 450cm) in coastal environment of the Andaman Sea (15oN, 96oE, southwestern Myanmar) was used to reconstruct the paleo-environmental change over the past 500 years. We find the evidence from 14C ages that the sediment rate decreased between about 150〜170 cm bsf (1600〜1750 cal yr A.D) of the core. Moreover, grain size analysis reveals finer between about the 150〜170 cm bsf part. Therefore, our results suggest the reduction of sedimentary supply into Andaman Sea coastal area from rivers around 1600〜1750 cal yr A.D. There is a possibility that these results were reflected various environmental changes (e.g. onshore precipitation).