Abstract:

Based on the field observation, interpretation of seismic, well data, and analysis of saltrelated structure styles, the research on the structural deformation characters in the middle of Kuqa depression was done. The result shows that: (1)The middle part of Kuqa depression can be separated into segments in westeast direction, belts in southnorth direction and layers in vertical. Four layers, overburden salt layer，salt layer, subsalt layer and basement layer, are divided in vertical. (2)The main structural styles in this area are contraction styles and salt tectonics. The distribution of structural styles are various in different segments. Different types of thrust and fold can be found in overburden layer. Saltrelated structural styles are mainly in salt layer and imbricate thrust fault and fold are in subsalt layer.(3)Distribution of fold belt in surface, salt tectonics and deformation in subsalt layer are three important factors which decide the differential deformation of Kuqa depression. It can be divided into four segmentations: BoziQuele segmentation, DabeiXiqiu segmentation, KeshenXiqiu segmentation and KL3Dongqiu segmentation.(4) The research on the balanced section and tectonic evolution history indicate that Kuqa depression experienced extensional depression stage in Mesozoic, bending depression stage from Paleogene to Miocene and intracontinental foreland basin from Pliocene to Quaternary. The present structures of the basins are mainly formed in the middlelate deposition period of Kuqa Formation.

Key words: middle part of Kuqa depression, saltrelated structure;structural style, character of segment, tectonic evolution