Metamorphism in the Sanbagawa belt of SW Japan as a record of subduction processes

Simon Richard Wallis

Presentation information

[E] Oral

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

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

Wed. May 29, 2019 3:30 PM - 5:00 PM A09 (TOKYO BAY MAKUHARI HALL)

convener:Timothy B Byrne(University of Connecticut), Asuka Yamaguchi(Atomosphere and Ocean Research Institute, The University of Tokyo), Jonny Wu(University of Houston), Kyoko Okino(Atmosphere and Ocean Research Institute, The University of Tokyo), Chairperson:Asuka Yamaguchi(Atomosphere and Ocean Research Institute, The University of Tokyo), Tim Byrne

4:30 PM - 4:50 PM

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

★Invited Papers

*Simon Richard Wallis¹ (1.University of Tokyo)

Keywords:Tectonics, Sanbagawa belt, subduction

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