库车坳陷东部构造分层变形特征及演化

根据库车坳陷东部地区的地面地质图、地震剖面和钻井等资料,对库车坳陷东部构造变形样式进行解析得出:库车坳陷东部构造呈现南北分带、东西分段、上下分层的几何学特点。以新近系下部的吉迪克组膏泥岩分隔,分为膏泥岩上变形层、膏泥岩变形层、膏泥岩下变形层和基底变形层4层模式。该区以发育收缩变形及膏泥岩塑性变形为主,上构造层、中构造层及下构造层的构造几何样式及分布具显著差异。上构造层以逆冲断层及收缩褶皱为主,中构造层发育膏泥岩塑性变形构造,下构造层以逆冲断层主导的推覆叠瓦构造为主。库车坳陷东部构造具有显著的分段变形特点,可细分为依西—东秋里塔格构造段、依奇克里克—迪那构造段、吐孜洛克—迪那构造段、吐格尔明—阳北构造段,特征差异主要表现在上构造层地面线性褶皱带、中构造层塑性变形样式和下构造层变形差异。该区构造演化剖面分析说明库车坳陷东部地区大致经历中生代(三叠纪—白垩纪)伸展断陷—坳陷盆地、古近纪挠曲过渡型盆地、新近纪—第四纪再生前陆盆地3个演化历程。现今构造定型于库车组沉积时期。

Differential Structural Deformation and Tectonic Evolution in the East of Kuqa Depression

Based on the surface geologic map, seismic profile, drilling data and other data about the east of Kuqa Depression, we analyzed the deformation style of structures in the east of Kuqa Depression and concluded that the eastern part of the Depression could be separated into segments in east-west direction, belts in south-north direction and layers vertically. Four layers, overburden gypsum mudstone layer, gypsum mudstone layer, sub-gypsum mudstone layer, and basement layer were divided vertically. The main structural styles in this area are contraction styles and gypsum mudstone layer tectonics. The distributions of structural styles are various in several segments. Different types of thrust fault and fold are in sub-gypsum mudstone layer. Distribution of fold belt in surface, gypsum mudstone tectonics and deformation in sub-gypsum mudstone layer are three critical factors which decide the differential deformation of Kuqa Depression. It could be divided into three segmentations:Yixi-Dongqiulitage segmentation, Yiqikelike-Dina segmentation, Tuziluoke-Dina segmentation and Tugeerming-Yangbei segmentation. Research on the balanced section and tectonic evolution history indicated that Kuqa Depression experienced extensional depression stage in Mesozoic, bending depression stage from Miocene and intercontinental foreland basin from Pliocene to Quaternary. The present structures of the basins were mainly formed in the mid-late deposition period of Kuqa Formation.