R8: Metamorphic rocks and tectonics

[R8P-10] Detrital zircon U-Pb age and metamorphic thermal structure of the Yokokawagawa metamorphic rocks in central Japan

*Hiroshi Mori¹, Hiroki Mizumura², Tetsuya Tokiwa¹, Kohei Yoshikawa¹, Yuki Nobe³, Yui Kouketsu⁴ (1. Shinshu Univ., 2. Kyowa Sekkei, 3. Electric Power Development, 4. Nagoya Univ.)

Keywords:Yokokawagawa, Sanbagawa, detrital zircon U-Pb dating, Raman carbonaceous material geothermometry

The Yokokawagawa metamorphic rocks (YMR) are commonly considered as a part of the Sanbagawa metamorphic rocks (SMR), but there is no consensus on the attribution of the YMR. In this study, we conducted detrital zircon U-Pb dating and metamorphic thermal analysis on the YMR. The results of the U-Pb dating imply that the depositional age is ~100 Ma or later and the temperatures estimated with Raman carbonaceous material geothermometry were ~350–380 ºC. These are consistent with results of the SMR, supporting the idea that the YMR attributes to the SMR.