Abstract:

Hongche fault belt in northwest margin of Junggar Basin is divided into four fault subzones, including Hongshanzui thrust fault, Zhongguai thrust fault, Chepaizi thrust fault in NS direction and Che 75-Che 77 well thrust fault in NWdirection. The plane distribution and formingmechanismof each thrust fault are analyzed. The growth index and fault throw are applied to study the typical structural section. The result shows that most of the contemporaneous thrust faults are main front faults and high angle imbricate thrust structures with basement involvement. The contemporaneous thrust faults are considered to be closely related to the deposits in the Permian, Triassic and Jurassic bottom. The thrust-napping was intense in Permian, as a result, the thrust faults developed universally. The developing degree of the faults in Triassic weakened fromnorth to south. While in Jurassic, the faults developed well in the middle part and poor in north part, and stopped developing in south part of this area. From Permian to Triassic, the development of the contemporaneous thrust faults is piggyback propagation, and it is overstep propagation fromTriassic to Jurassic.

Key words: array acoustic logging, time-frequency distribution, signal analysis, Choi-Williams energy distribution