日本地球惑星科学連合2021年大会

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セッション記号 S (固体地球科学) » S-CG 固体地球科学複合領域・一般

[S-CG45] 海洋底地球科学

2021年6月5日(土) 10:45 〜 12:15 Ch.19 (Zoom会場19)

コンビーナ:沖野 郷子(東京大学大気海洋研究所)、座長:新井 隆太(国立研究開発法人海洋研究開発機構)、藤井 昌和(国立極地研究所 / 総合研究大学院大学)

12:00 〜 12:15

[SCG45-12] Examining the origin and depositional process of turbidites in the southern part of Okinawa Trough based on cores from Expedition KH-21-3

*蔡 之榕1、成瀬 元1、池原 研2、- KH-21-3乗船研究者一同 (1.京都大学大学院理学研究科、2.産業技術総合研究所地質情報研究部門)


キーワード:沖縄トラフ、混濁流、タービダイト

Okinawa Trough is an actively rifting back-arc basin and an important area for examining the tectonic history of the Ryukyu subduction zone. Past studies showed that the main sources of sediment deposition in the southern part of Okinawa Trough were Taiwan and the East China Sea continental shelf. The main process of sediment transportation to the Okinawa Trough was turbidity currents in addition to hemipelagic sediment transport. Estimating sediment flux from Taiwan as well as local sediment input from volcanic arcs into this region is important for understanding the development of the Okinawa Trough and the temporal changes in orogenic activity in Taiwan. However, the scale and source of turbidity current events related to the depositional process within the region is still unclear.

The KH-21-3 expedition surveyed the southern part of Okinawa Trough and four piston cores were obtained. Each core contained more than one turbidite unit. In order to better understand the origin and scale of turbidity current events that resulted in turbidites in the southern part of Okinawa Trough, we conducted a 2D numerical experiment of turbidity current events using a shallow water equation model that reproduced turbidites in borehole cores. This presentation will also contain a preliminary report of the characteristics of turbidites within the cores obtained from KH-21-3 and an overview of the numerical model used for simulation.