R6: Plutonic rocks, volcanic rocks and subduction factory

[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.