2021 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)

Presentation information

Oral presentation

R6: Plutonic rocks, volcanic rocks and subduction factory

Thu. Sep 16, 2021 9:30 AM - 12:00 PM Zoom Session 2

Chairperson:Tatsuhiko Kawamoto(Shizuoka University), Atsushi Kamei(Shimane University), Masao 伴 Ban(Yamagata University)

10:45 AM - 11:00 AM

[R6-05] Gabbro–Diorite–Tonalite complex: Formation of juvenile crust in active continental margin, Cretaceous north Kyushu batholiths, southwest Japan

*Masaaki Owada1, Shungo Toyama4, Atsushi Kamei2, Yasuhito Osanai3, Nobuhiko Nakano3, Tatsuro Adachi3 (1. Yamaguchi Uni. Sci., 2. Shimane Uni. Sci., 3. Kyushu Uni. Int. Sci., 4. AI United Eng. Inc.)

Keywords:High-Nb basalt, High-Mg andesite, Adakite, Slab rollback

The gabbro–diorite–tonalite complex in the Sefuri Mountains, north Kyushu geochemically resembles high-Nb basalt, high-Mg andesite, and adakite, respectively, and shows juvenile character with positive epsilon Nd isotopic compositions. Considering the early Cretaceous tectonic setting, the magmatism occurred as an unusual heat flow due to mantle upwelling affected by the slab rollback.