R8: Metamorphic rocks and tectonics

[R8-01] Zircon–monazite–garnet behaviours during high-grade metamorphism in the Kontum Massif, Vietnam

*Vuong Thi Sinh Bui¹, Yasuhito Osanai², Nobuhiko Nakano², Tatsuro Adachi², Ippei Kitano², Masaaki Owada³ (1. ISGS, Kyushu Univ., 2. SCS, Kyushu Univ., 3. Sci, Yamaguchi Univ.)

Keywords:In situ U–Th–Pb ages, zircon, monazite, garnet, Kontum Massif

The Kontum Massif, central Vietnam composes of three main complexes: the Kannack (KC), Ngoc Linh (NLC) and Kham Duc Complexes (KDC). This study carried out monazite EPMA dating and zircon LA-ICP-MS dating from pelitic gneisses and mafic granulites from all three complexes, combining with zircon–monazite–garnet geochemistry. The results indicated that the ca. 250 Ma high temperature metamorphism in the KC, two high-grade metamorphic events at ca. 440–450 and 240–250 Ma in the NLC, and the medium pressure metamorphism at ca. 240 Ma in the KDC.