Discussion on the sinistral strike-slip age and tectonic background of north-east fault in southern Anhui Province

Lying in the east of the Yangtze plate, southern Anhui experienced multiple periods of magmatic activity and tectonic deformation related to the subduction of the Paleo-Pacific Plate during the late Mesozoic. As an important structure controlling the tectonic framework, the NE-trending fault has undergone multiple stages of evolution since the Indosinian period. Previous studies mainly focused on the active stages of faults, and there were disputes on the active periods of each stage, which restricted the in-depth study of tectonic evolution in southern Anhui and even eastern China since Mesozoic. The field investigation reveals that sinistral strike-slip deformation of the NE-trending fault in southern Anhui is actually a high-angle translational fault. The inversion of the paleo-tectonic stress field indicates that it was formed in the NNE-SSW compression environment. Zircon U-Pb geochronology and stratigraphic cutting relationship indicate that its sinistral strike-slip age is at the end of Early Cretaceous. Combined with previous studies on paleontology and stratigraphy, it is believed that its sinistral strike slipping was formed in 121-110Ma, and may be related to the movement direction change of the Izenizaki Plate at the end of the Early Cretaceous.