A Study of Metamorphism of Metapelites from the Kuanping Group,
In this paper, the authors report petrological results on four garnet-bearing metapelites from this group, including a staurolite-kyanite-bearing sample collected from the Huilongsi Formation, and a sillimanite-bearing sample taken from the Zuolaozhuang Formation. Garnet from samples in the Huilongsi Formation exhibits a pronounced compositional zoning that resulted from progressive metamorphism, whereas that from samples in the Zuolaozhuang Formation is weakly affected by late low-temperature diffusion. The close association of lower-upper amphibolite facies Kuanping Group, lower amphibolite facies Erlangping Group and granulite facies Qinling Group with similar metamorphic ages (440~400 Ma) suggests that collisional orogenesis occurred between arc, microcontinent and southern margin of the North China craton during the Silurian to the Early Devonian.