Abstract:The Xichangjing Group is related to late Neoproterozoic glaciation in the Beishan orogen, which is of great significance to understand the Precambrian tectonic evolution. The field investigation, geochronology, and zircon Lu- Hf isotope were conducted on the Xichangjing Group of the Pochengshan area. The results show that it is characterized by glacial sedimentation. The ages of the youngest detrital zircons are 579±12 Ma and 574±8 Ma for pelitic siltstone and silty- fine sandstone. Combined with the parallel unconformity between the Xichangjing Group and the overlying early Cambrian Shuangyingshan Formation, the sedimentary age of the Xichangjing Group is limited to the late Ediacaran. There is a single age peak (635~631 Ma) for detrital zircons of the clastic rocks from the Xichangjing Group, and during this period the crustal Hf model ages of zircons are mainly concentrated in 1.52~0.60 Ga, which shows the crustal growth and reworking of the Mesoproterozoic crust. The Xichangjing Group is obviously similar to the Talisayi Formation in the Tianshan orogen. Moreover, the Xichangjing Group has some detrital zircons associated with ~0.9 Ga and ~1.4 Ga magmatism in the Beishan orogen. Its gravel is mainly composed of dolomite, siliceous dolomite and a small amount of quartzite, which are consistent with the rock associations of the Pingtoushan Formation and Gudongjing Group. Therefore, it is believed that the detrital materials of the Xichangjing Group were derived from the Beishan orogen. In addition, the Xichangjing Group was formed by the synthetical effects of glacier and water erosion in middle- high latitude. We further suggest that the Beishan and Tianshan were located in the same tectonic location during late Ediacaran, which had been separated from an ancient craton, and they might have been subjected to the subduction.