ANALYSIS ON THRUSTINGS OF THE MAZHATAGE STRUCTURAL BELT IN THE TARIM BASIN
Yang Haijun1, Li Yuejun2, Feng Xiaojun3, Zheng Min2, Zhang Chunlian3, Zhao Yan2
1. China University of Geosciences, Wuhan 430074; 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029; 3. Tarim Oilfield Branch Company, China National Petroleum Corp., Korla, Xinjiang 841000
The Mazhatage structural belt is a boundary between the Markit Slope and the Bachu Fault-Uplift in the Tarim Basin.The Hetianhe(Hetian River) Gasfield was discovered in Markit-Bachu area,and the fault structures were one of the dominant factors for trap-formation and hydrocarbon migration and accumulation.On the basis of seismic section interpretation,3 generations of thrusting structures were recognized in the Mazhatage structural belt.The first generation occurred in Late Cretaceous or towards the end of Cretaceous,when the detachment occurred along the Middle Cambrian gypsum-salt layer and the strata thrust from Markit to Bachu,accompanied with the fault-propagation folding,which resulted in creation of the Mazhatage anticline belt.The second generation occurred towards the end of Miocene,when the basement-involved faults formed,composed of the parallel South Mazhatage and North Mazhatage fractures,and the both making up a back-thrust structure.The third generation developed in Pleistocene to Holocene.In this period,the Cenozoic rocks detached and slided along the basal gypsum-salt layer of the Paleogene,and over-thrust northeastwards,from the Markit Slope to the Bachu Fault-Uplift.The faut-propagation fold was formed in the upper wall of the thrust in the neotectonic period.Based on what mentioned above,the relation between development of the Mazhatage structural belt and the regional tectonic evolution in Late Mesozoic and Cenozoic was explored.