R8: Metamorphic rocks and tectonics

[R8-09] Significance of talc-calcite vein from the Yaeyama metamorphic rocks

*Masahiro Yoshikawa¹, Kenji Asakura¹, Takao Hirajima¹ (1. Kyoto Uni.)

Keywords:Talc, Calcite, Yaeyama metamorphic rocks

To investigate fliud activity in the Yaeyama metamorphic rocks, we studied mineral veins developed in the metamorphic rock. Here we report talc(Tlc)-calcite(Cal) bg.vein developed in mafic schist with epidote and actinolite. The following reaction is inferred from the development of Tlc in the vein:
6Cal+5Tlc+4SiO2=3Act+6CO2+2H2O
Thermodynamic analysis suggest that Tlc-Cal assemblage can be formed by infiltration of H2O-rich fluid during the exhumation stage.