Japan Geoscience Union Meeting 2022

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[J] Oral

B (Biogeosciences ) » B-CG Complex & General

[B-CG05] Decoding the history of Earth: From Hadean to the present

Sun. May 22, 2022 1:45 PM - 3:15 PM 304 (International Conference Hall, Makuhari Messe)

convener:Tsuyoshi Komiya(Department of Earth Science & Astronomy Graduate School of Arts and Sciences The University of Tokyo), convener:Yasuhiro Kato(Department of Systems Innovation, Graduate School of Engineering, University of Tokyo), Katsuhiko Suzuki(Submarine Resources Research Center, Japan Agency for Marine-Earth Science and Technology), convener:Kentaro Nakamura(Department of Systems Innovation, School of Engineering, University of Tokyo), Chairperson:Yuki Tomimatsu(Department of Earth and Planetary Sciences, Kyushu University), Tsuyoshi Komiya(Department of Earth Science & Astronomy Graduate School of Arts and Sciences The University of Tokyo)

2:30 PM - 2:45 PM

[BCG05-16] High resolution Si isotope profile of pelagic radiolarites across the Triassic – Jurassic extinction interval

Maximilien Bole1,4,5, *Masayuki Ikeda1, Takayuki Ushikubo2, Rie Hori, S.3, Peter Baumgartner5, Yuki Nakai4 (1.University of Tokyo, 2.Kochi University, 3.Ehime University, 4.Shizuoka University, 5.Lausanne University)

Keywords:Triassic-Jurassic boundary mass extinction, Si isotope

The end-Triassic extinction event (ETE) marks one of the “Big five” mass extinction events of the Phanerozoic, yet the timing and nature of global environmental changes on a global scale remain elusive. Here we report mm-scale high-resolution δ30Si profile of sea surface-dwelling radiolaria, preserved as molds, spanning the end-Triassic radiolarian turnover interval of the deep-sea succession at the Katsuyama section, Inuyama, Japan. The δ30Si of the Triassic-Jurassic radiolarian molds between -0.6±0.5‰ and 2.6±0.3‰ overlap with available radiolarian δ30Si data for Triassic to Cenozoic, including modern samples. The mass balance of Si with dominant radiolaria molds up to 90% in chert supports the negligible impact of diagenesis on δ30Si of radiolarian mold. The cm-scale δ30Si variations up to 2 ‰ are overall associated with changes in silica contents.