Japan Geoscience Union Meeting 2015

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Symbol S (Solid Earth Sciences) » S-CG Complex & General

[S-CG64] Ocean Floor Geoscience

Thu. May 28, 2015 2:15 PM - 4:00 PM A05 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Kyoko Okino(Ocean Research Institute, University of Tokyo), Keiichi Tadokoro(Research Center for Seismology, Volcanology and Earthquake and Volcano Research Center, Nagoya University), Osamu Ishizuka(Geological Survey of Japan, AIST), Tomohiro Toki(Faculty of Science, University of the Ryukyus), Narumi Takahashi(Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology), Chair:Mikiya Yamashita(Japan Agency for Marine-Earth Science and Technology), Tomohiro Toki(Faculty of Science, University of the Ryukyus)

3:45 PM - 4:00 PM

[SCG64-36] The changes of past sea-bottom environment deduced from the recent benthic foraminifera Southern off Costa Rica

*Hitomi UCHIMURA1, Shiro HASEGAWA2, Hiroshi NISHI2 (1.Department of Earth Science, Tohoku University, 2.Tohoku University Museum)

Keywords:the recent benthic foraminifera, Paleobathymetory, the erosional subduction zone, southern off Costa Rica

IODP Exp.344 (Costa Rica Seismogenesis Project: CRISP 2) is designed to understand the processes that control nucleation and seismic rupture of large earthquakes at erosional subduction zones and drilled five sites off the western coast of Costa Rica around the southern end of the Middle America Trench, where the oceanic Cocos Plate is subsiding beneath the Carribbean Plate. In this cruse, the benthic foraminiferal data were strongly needed because the distribution of recent living benthic foraminifera is essential tool to estimate the past bottom-ocean environment and paleobathymetory. However, there are few data about the distribution of the recent foraminifera southern off Middle America.
In this study, we have recognized six assemblages out of samples of southern off Costa Rica.
And we identified the the shallower-water environment assemblages of U1413 using these recent data.