Japan Geoscience Union Meeting 2014

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Symbol S (Solid Earth Sciences) » S-IT Science of the Earth's Interior & Techtonophysics

[S-IT41_28PM1] Origin, Evolution, Destruction, and Recycling of Oceanic Plate

Mon. Apr 28, 2014 2:15 PM - 4:00 PM 314 (3F)

Convener:*Tomoaki Morishita(School of Natural System, Colleage of Science and Technology, Kanazawa University), Toshitsugu Yamazaki(Atmosphere and Ocean Research Institute, The University of Tokyo), Nobukazu Seama(Department of Earth and Planetary Sciences, Graduate School of Science, Kobe University), Ryo Anma(Faculty of Life and Environmental Science, University of Tsukuba), Hidenori Kumagai(Independent Administrative Institution, Japan Agency for Marine-Earth Science and Technology), Daisuke Nakamura(Okayama University), Chair:Katsuyoshi Michibayashi(Institute of Geosciences, Shizuoka University), Ryoko Senda(Institute for Research on Earth and Evolution, Japan Agency for Marine-Earth Science and Technology)

3:30 PM - 3:45 PM

[SIT41-14] Mafic minerals within a sediment core sampled by ABISMO in Mariana Trench

*Katsuyoshi MICHIBAYASHI1, Naonobu TERUMINE2, Yumiko HARIGANE3, Takuro NUNOURA4, Shigeki UEHARA1, Yasuhiko OHARA5, Junichi MIYAZAKI4, Ken TAKAI4 (1.Institute of Geosciences, Shizuoka University, 2.Institute of Geosciences, Shizuoka University, 3.AIST/GSJ, 4.JAMSTEC, 5.Hydrographic and Oceanographic Department of Japan)

Keywords:ABISMO, Mariana Trench, Challenger Deep, sediment core, spinel, olivine

Mariana Trench is one of the deepest oceans in the world more than 10,000 m depth. Although the mantle section outcrops along the land-side slope of the southern Mariana Trench, the studied depth so far is approximately shallower than 7,000 m and therefore few geological information is available for the mantle section deeper than 7,000 m. In 2008, a sediment core has been sampled at 10,350 m in Challenger Deep of Mariana Trench by ABISMO (Automatic Bottom Inspection and Sediment Mobile) during KR08-05 cruise. The sediment core is 161.5 cm in length and contains mafic sandy grains such as olivine and spinel. In this study, we sampled the mafic minerals from the sediment core and analyzed their major element compositions. As a result, the chemical compositions of the mafic sandy grains were compatible with those of mafic minerals within the peridotites along the land-side slope of Mariana Trench shallower than 7,000 m. We will discuss the origin of these sandy grains.