Metamorphism and geodynamics at the south boundary of the Dabie eclogite terrain, China

摘要

The south boundary of the Dabie eclogite terrain is concordant with the south margin of the granitic gneiss with eclogite blocks. The boundary extends west-east along Taihu-Mamiao with a south dip. The range of the peak metamorphic pressure-temperature is estimated from the eclogite as 2.0-2.5 GPa and 460-520 deg. C, as suggesting a paleo-geothermal gradient as low as 7-10 deg. C/km. The mafic blocks, amphibolite and garnet-amphibolite, in mica-gneiss on the south of the boundary experienced metamorphism of epidote amphibolite facies.