[SGL33-P12] Deformation characteristics and metamorphic temperature of the high-pressure terrace of the Taiwan orogeny
Keywords:Raman Spectroscopy of Carbonaceous Material, fission track dating, structural analysis, high-pressure Yuli Belt, Taiwan orogeny
Three-stage foliations have been observed in eastern Central Range. The S1 is parallel to S0 associated with well-growth mica which is related to the highest metamorphism. The S2 is high-angle dipping foliation with fine-grain mica growth associated with tight to isoclinal folding. The S3 is shallow dipping foliation associated with small to mesoscale recumbent folding. The S3 results from the vertical force, which is strongly related to the recent exhumation process.
The RSCM results show the metamorphic temperature increases from ca. 340oC (low-grade slate) to ca. 500oC (high-pressure belt) in short distances that might infer a high shear zone; however, the zircon fission-track ages are similar in 0.7-1Ma and the eastern Central Range accelerate exhumation since ca. 2Ma simultaneously indicating the different metamorphic terranes have been merged before 2Ma. We suggest that the later stage foliation S2-S3 is related to this rapid exhumation process and the S1 is associated with the highest metamorphism suggesting it could be related to the subduction process.