Japan Geoscience Union Meeting 2015

Presentation information

Print

Oral

Symbol B (Biogeosciences) » B-PT Paleontology

[B-PT23] Decoding the history of Earth: From Hadean to Modern

Mon. May 25, 2015 4:15 PM - 6:00 PM 104 (1F)

Convener:*Tsuyoshi Komiya(Department of Earth Science & Astronomy Graduate School of Arts and Sciences The University of Tokyo), Yasuhiro Kato(Department of Systems Innovation, Graduate School of Engineering, University of Tokyo), Katsuhiko Suzuki(Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology), Chair:Koichiro Fujinaga(Frontier Research for Energy and Resources, School of Engineering, University of Tokyo), Yutaro Takaya(Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology)

4:30 PM - 4:45 PM

★ [BPT23-22] Acoustic characterization of deep-sea sediments by sub-bottom profiler

*Kentaro NAKAMURA1, Shiki MACHIDA2, Yuka MASAKI3, Kyoko OKINO4, Koichi IIJIMA3, Katsuhiko SUZUKI3, Yasuhiro KATO1, KR13-02, Cruise menbers 3, MR13-E02 LEG2, Cruise menbers 3, KR14-02, Cruise menbers 3, MR14-E02, Cruise menbers 3 (1.Univ. of Tokyo, 2.Waseda Univ., 3.JAMSTEC, 4.AORI, Univ. of Tokyo)

Subbottom profiling was conducted in the Japanese Exclusive Economic Zone (EEZ) around Minamitorishima Island to reveal the distribution of REY-rich mud in the Minamitorishima EEZ. Based on the shape and pattern of the reflectors, three discrete acoustic facies of opaque (O) type, transparent (T) type, and layered (L) type were distinguished. Distribution of the O-type facies is restricted to just on or immediate vicinity of seamounts, suggesting that this acaustic facies corresponds to rocky outcrop without soft sediment cover. The T-type facies occurs in northern part and southern to southeastern part of the Minamitorishima EEZ, whereas the L-type facies widely covers central part of the area. By comparing the sub-bottom profiler record with sediment core samples obtained by piston coring shows that the acoustic facies T corresponds to REY-rich mud, whereas acoustic facies L corresponds to non-REY-rich terrigenous sediment.