R8: Metamorphic rocks and tectonics

[R8-04] Process and timing of ultrahigh-temperature metamorphism of metagabbro from the Kurosegawa tectonic belt in Kyushu

*Yasuhito Osanai¹, Nobuhiko Nakano¹, Ippei Kitano², Masaaki Owada³, Vuong Bui Thi Sinh⁴, Dolzodmaa Boldbaatar¹ (1. Kyushu Univ., 2. Hokkaido Univ., 3. Yamaguchi Univ., 4. Vietnam Academy of Science and Technology)

Keywords:Kurosegawa tectonic belt, UHT metamorphism, Grt-Cpx granulite, Ordovician magmatism, Permo-Triassic metamorphism

Ultrahigh-temperature metamorphic rocks of the Kurosegawa tectonic belt in Eastern Kyushu derived from ca. 450 Ma volcanic-arc type gabbro, and metamophosed under the peak P-T conditions of 950-1050°C and 10-12 kbar. Partial melting also took place during the near isothermal decompression and formed Opx-Pl corona after the breakdown of Grt.