REGIONAL STRUCTURAL EVOLUTION OF THE XIHE CHENGXIAN AREA, GANSU

According to the latest data of 1∶50 000 regional surveys in the Xihe Chengxian area, the Xihanshui system is disintegrated. The Middle Upper Proterozoic Haijiushan Formation and Upper Silurian Shuangliuzhou Formation have been newly established. On the basis of a detailed structural analysis, a succession of tectonic evolution since the Paleozoic has been set up .