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Geoscience ›› 2023, Vol. 37 ›› Issue (02): 296-306.DOI: 10.19657/j.geoscience.1000-8527.2022.035

• Structural Geology • Previous Articles     Next Articles

Layered Deformation Characteristics, Formation Mechanism of Strike-slip Faults on the Western Margin of Mosuowan Uplift,Junggar Basin

TIAN Anqi1,2(), CHEN Shi1,2(), YU Yixin1,2, XIU Jinlei3, JIN Feng1,2   

  1. 1. School of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China
    2. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China
    3. Research Institute of Exploration and Development, Shengli Oilfield Company, SINOPEC, Dongying,Shandong 257000, China
  • Received:2022-04-02 Revised:2022-06-20 Online:2023-04-10 Published:2023-05-23
  • Contact: CHEN Shi

Abstract:

Many strike-slip faults are developed around the Mosuowan uplift in Junggar basin, with complex deformation characteristics. Due to the limit seismic data quality, the time division of fault activity is different, with the formation mechanism unknown. Taking the Zhengshacun area on the western margin of Mosuowan uplift as an example, we studied the geometric morphology and kinematic characteristics of strike-slip faults at Zhengshacun. The results show that the strike-slip faults at Zhengshacun have layered differential deformation, which is mainly divided into three layers. The deep structural layer is Permian, which develops two strike-slip fault groups in near N-S and near E-W directions. The E-W-trending faults cut the nearly N-S sinistral faults, and the section is mainly in negative flower structure style. The middle structural layer of Triassic-Jurassic Badaowan Formation only developed near E-W trending faults, forming horsetail, flat and overlapping structural styles on the plane, and the section developed positive flower structure. The fault strike of Jurassic Sangonghe Formation in the shallow structural layer is near E-W directed, which is linearly distributed on the plane, and the section is dominated by flexural deformation. The faults in the three structural layers are superimposed and developed to form vertical linear, Y-shaped and flower-shaped structural styles, in which the near N-S directed faults are dextral strike-slip and the near E-W directed ones are sinistral strike-slip. Evolution of the Zhengshacun fault are divided into three stages. In the Late Permian, the Junggar block rotates counterclockwise to form a near N-S strike-slip fault, showing a negative flower structure. In the early Jurassic, the NE-SW compressive stress of Tianshan formed a near E-W strike-slip fault, showing a positive flower structure. In the Late Jurassic, a few near E-W faults are inherited and developed.

Key words: Junggar basin, strike-slip fault, activity period, delamination deformation, formation mechanism

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