Study on differentiation cause about tectonic evolution of northern and southern segments in Ningdong Coalfield

In order to discuss the influence of tectonic evolution process on the present hosting condition of coal series, based on the tectonic dynamics backgroun d, the tectonic evolution process and its differentiation genesis of northern and southern segments in Ningdong Coalfield were analyzed by using the tectonic subsidenc e history and tectonic stress field recovery. It showed that the tectonic evolution process of Ningdong Coalfield was complicated due to the joint control of different tecto nic units.The subsidence history of the coalfield was obviously different from west to east. Due to the different position of the thrust nappe structure system, the uplifting denudation in the west is larger than that in the east.The tectonic stress field of coalfield was obviously different from north to south. Due to the different thrust nappe te ctonic systems, the direction of maximum compressive stress in the north and south of the stress field is not the same.The tectonic evolution was mainly affected by the control of the northern Qllian fold belt and the Alashan block. The north and south segments belonged to the Liupanshan and Helan Mountain thrust nappe tectonic syst ems, and the western force was stronger than the eastern part.