Geological Tectonics Control on the Karstic Water in the South Margin of the Ordos Basin

In the southern margin of Ordos basin,it is dry and lack of water,which restricts the economic development and the life quality of the people in the area.Through drawing investigation,drilling verification and rift structure and multidisciplinary studies,a systematic study of the karstic water in the southern margin of Ordos basin was carried out.The results show that the development of karst and karstic water are subject to the control of rift structure.NE-trending rift has a strong water yield property,and is a rift of control water.Compared with NE-trending rift,the NW-trending rift karst of compression-shear or fault-twisting is worse.Nearly east-west compressive fracture,water yield property is worse,and is a water-blocking rift.Interaction among the three major tectonic belts formed a grid-like and layered undergro und piping system.It has the control effect on alternating karstic groundwater,migration and enrichment,runoff and drainage of karstic water.