CENOZOIC TECTONIC EVOLUTION OF THE EASTERN QIULTAG STRUCTURAL BELT,KUQA FORELAND BASIN IN XINJIANG
Jin Wenzheng1, Tang Liangjie1, Wang Qinghua2, Wan Guimei1, Yang Wenjing2, Yu Yixin1, Peng Gengxin2
1. Basin and Reservoir Research Center, China University of Petroleum, Beijing 102249; 2. Research Institute of Petroleum Exploration and Development, Tarim Oil-field Branch Company, China National Petro-leum Corp., Korla, Xinjiang 841000
The eastern Qiultag structural belt,which was on the southern edge of Kuqa foreland basin,has occurred tense tectonic compression and subsidence during Cenozoic.The tectonic evolution history was analyzed by means of the balanced cross section,the growth strata and the numerical modeling of some key wells’subsidence history.The results showed that the tectonic movement was relatively weak and the subsidence rate was minimal during sedimentary stage of the Kumugeliemu Group in age of Paleocene to Eocene.The tectonic activity began to enhance and the subsidence rate increased,and therefore developed some thrusts with small fault displacement during sedimentary stage of the Suweiyi Formation in age of Oligocene.The tectonic movement enhanced further and the subsidence rate increased again during Miocene,so that deposited thick salt layer of the Jidike Formation,then the salt layer flowed by tectonic compression and formed salt pillow during the sedimentary stage of Kangcun Formation,when the growth strata occurred.Subsequently,the studied area subsided quickly during depositional stage of the Kuqa Formation in age of Pliocene.With the South Tianshan Mountains uplifted rapidly,the thrust expanded southwards rapidly,and the front of the Kuqa fold-and-thrust belt arrived the eastern Qiultag structural belt in Early Pleistocene when the regional tectonics fell into its pattern.To sum up,the tectonic deformation was tense in this area where developed many thrusts,and the salt layer flowed evidently and formed salt nappe.