Tectonic analysis on Tumuxiuke fault belt in the western Tarim Basin
Liu Yalei1, Yang Haijun2, Qi Yingmin2, Hu Xiufang3, Wang Yueran2, Li Yuejun1, Wang Haiyan2, Zhao Yan1, Zhang Qiang1, Wen Lei1
1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029;
2. Tarim Oilfield Branch Company, PetroChina, Korla, Xinjiang 841000;
3. Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058
The Tumuxiuke fault belt,which locates in the western Tarim Basin,is a large-scale basement-involved fault zone and forms the boundary between the Awati Sag and Bachu fault-uplift(sub tectonic units of Tarim Basin).Based on systematic interpretation on seismic data,three sections of different tectonic features can be divided:the west,the middle and the east section.In the west section,there only develops a basement-involved high-angle thrust fault which dips towards the Bachu fault-uplift; while in the middle section,besides the main Bachu-inclining fault mentioned above,a reversed-inclination recoil fault becomes increasingly clear and gradually draws the outline of wedge-shaped thrust structures.Meantime,on the upper plate of the recoil fault,a series of Quaternary normal faults develop; however,in the east section,the Bachu-inclining main fault has its top stopped at Mid-Cambrian,while the unbroken strata above Mid-Cambrian have their thrust displacement completely absorbed by the Awati-inclining recoil fault,which finally make up of the typical wedge-shaped thrust structures.According to the seismic interpretation,we conclude that mainly two generations of fault tectonics exist in the Tumuxiuke fault belt:the deeper high-angle basement-involved thrust fault zone and the shallower overlaid normal faults.The former formed in early Neogene and finally stabilized in Late Neogene; the latter is a new discovery in this paper which formed in the Early-Middle Quaternary and it only developed in the middle section of the Tumuxiuke fault belt..