›› 2019, Vol. 40 ›› Issue (1): 1-1.doi: 10.7657/XJPG20190107

   

Structural Deformation Styles and Tectonic Evolution Characteristics in Eastern Kuqa Depression

ZHANG Wei, XU ZhenpingZHAO Fengquan, WU Shaojun, HUANG Cheng, ZHANG Xueqi   

  1. (Research Institute of Exploration and Development, Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China)
  • Online:2019-02-01 Published:1905-07-15

Abstract: Through analyzing geological maps, seismic section and drilling data, the tectonic deformation styles of the eastern Kuqa depression are studied. The study results show that the structures in the eastern Kuqa depression have some geometric features: banding along N-S orientation, segmentation along W-E orientation and zonation vertically. Taking the gypsum-mudstone layer of the Paleogene Jidike formation as a barrier, 4 layers such as structural layer above gypsum-mudstone, gypsum-mudstone layer, structural layer under gypsum-mudstone and basement are classified. The shrinkage distortion and the plastic deformation of the gypsum-mudstone are dominant in the study area, and the tectonic styles and distributions of the upper structural layer, gypsum-mudstone layer and lower structural layer are significantly different. The upper structural layer is dominated by thrust faults and constricted folds, the gypsum-mudstone layer by plastic deformation structures and the lower structural layer by nappe imbricate structures dominated by thrust faults. The structures in the eastern Kuqa depression display an obvious characteristic of segmented deformation, which can be divided into 4 structural segments, i.e., Yixi-Eastern Qilitage, Yiqikelike-Dina, Tuziluoke-Dina and Tugerming-Yangbei, whose differences are manifested in the distribution of the linear fold belt on the surface of the upper structural layer, the plastic deformation style of the gypsum-mudstone layer and the deformation differences of the lower structural layer. The sections of structural evolution indicate that the eastern Kuqa depression experienced 3 evolution processes including extensional faulted-depression-depression basin in Mesozoic, bending transitional basin in Paleogene and regenerated foreland basin from Neogene to Quaternary. The present structures in the depression were mainly formed in the depositional period of Kuqa formation.

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