日本地球惑星科学連合2019年大会

講演情報

[E] 口頭発表

セッション記号 S (固体地球科学) » S-IT 地球内部科学・地球惑星テクトニクス

[S-IT26] New perspectives on the geodynamics of East Asia

2019年5月29日(水) 15:30 〜 17:00 A09 (東京ベイ幕張ホール)

コンビーナ:Timothy B Byrne(University of Connecticut)、山口 飛鳥(東京大学大気海洋研究所)、Jonny Wu(University of Houston)、沖野 郷子(東京大学大気海洋研究所)、座長:山口 飛鳥(東京大学大気海洋研究所)、Tim Byrne

16:30 〜 16:50

[SIT26-11] Metamorphism in the Sanbagawa belt of SW Japan as a record of subduction processes

★Invited Papers

*ウォリス サイモン1 (1.東京大学)

キーワード:テクトニクス、三波川帯、沈み込み

The Sanbagawa belt of SW Japan records Cretaceous suduction processes off the eastern Asian margin. The Sanbagawa belt can be traced for around 800 km throughout SW Japan, but the main exposure is found in Shikoku. The main constituent rock types are pelitic, quartz and mafic schists which were derived from the subducted oceanic slab. These are associated with widespread blocks and lenses of serpentinite and related rocks types derived from the mantle wedge.

A long running dispute about the age of peak metamorphism has recently been resolved. Evidence for an early stage of subduction associated at around 115 Ma is locally preserved with anticlockwise P-T paths. This is followed at around 90 Ma by the main been long disputed with estimates of the peak