R8: Metamorphic rocks and tectonics

[R8-07] UHT metamorphic rocks from northern Mogok, Myanmar

Khaing Nyein Htay², *Yasuhito Osanai¹, Nobuhiko Nakano¹, Bolgbaatar Dolzodmaa⁴, Ippei Kitano³, Zaw Htet⁴, Tatsurou Adachi¹, Masaaki Owada⁵ (1. Kyushu Univ. SCS, 2. GIM, Myanmar, 3. Tochigi Pref. Mus., 4. Kyushu Univ. ISGS, 5. Yamaguchi Univ.)

Keywords:Mogok metamorphic belt, UHT metamorphism, Spl-Qz symplectite, Opx-Spl-Crd corona, Oligocene

Two types of UHT-metamorphic rocks have been newly found from Mogok metamorphic belt in Myanmar. Those are Spl-Qz symplectite bearing Grt-Sil-Qz-Kfs felsic gneiss and Grt-Opx-Crd-Sil granulite including Opx-Crd-Spl symplectite. Estimated metamorphic P-T conditions of these UHT-metamorphic rocks show 5.5 - 8 kbar and 850 - 1000 ℃, and LA-ICP-MS zircon U-Pb dating indicate various inherited ages ranging from 3100 to 60 Ma and concordant metamorphic age of 26.56±0.76 Ma.