S3: Tectonics of East Asia (Special Session)

[S3-02] Multi-stage metamorphic history of the Oki gneisses in Japan: Implications for Paleoproterozoic metamorphism
and tectonic correlations in northeastern Asia

*Takeshi Imayama¹, Ryoichi Kawabata¹, Takenori Kato², Chang Whan Oh³, Kenji Horie⁴, Mami Takehara⁴ (1. Okayama Univ. of Sci., 2. Nagoya Univ., 3. Jeonbuk National Univ., 4. NIPR)

Keywords:Multi-stage metamorphic history, Oki belt, Paleoproterozoic metamorphic event, Triassic tectonic event

In the Oki belt, the M1 stage occurred c. 1.85 Ga with high-T granulite-facies metamorphism which was overprinted by c. 230 Ma high-grade metamorphism (M2) and retrograde amphibolite-facies recrystallization (M3). The Oki gneisses are fragments of a Precambrian terrane rather than Paleozoic sediments derived from the terrane. The Oki belt geologically corresponds to the northern Gyeonggi Massif in South Korea due to their similar Paleoproterozoic and Triassic tectonothermal events.