先存断裂与膏盐岩发育对库车坳陷东部构造变形的影响

Influence of pre-existing faults and gypsum salt deposits on structural deformation in the eastern Kuqa Depression

先存断裂和膏盐岩发育对构造变形具有重要的控制作用。库车坳陷东部在褶皱数量、构造样式、构造演化过程等方面具有较大的空间差异性,表现出明显的构造分段性。本文在野外地质调查、钻井和地震资料解释的基础上,分析了库车坳陷东部各段整体的构造变形特征和构造演化过程,认为:库车坳陷东部可以划分为吐格尔明段和依奇克里克—亚肯段;吐格尔明段构造形态较为简单,整体上为一个背斜,表现为受高角度先存基底断裂控制,新生代构造变形被限制在先存断裂上盘,并具有后展式的特点,背斜高点向北迁移;依奇克里克—亚肯段表现出多排背斜、后缘基底卷入与前缘薄皮滑脱、分层变形和前展式的特点,表明其构造变形受先存断裂和吉迪克组膏盐岩共同控制。先存断裂与膏盐岩发育特征是影响库车坳陷东部构造变形时空差异性的重要因素。

The pre-existing faults and the development of gypsum salt deposits play an important role in controlling structural deformation.There are considerable differences in fold number,structural style and structural evolution,which show obvious structural segmentation.Based on the field geology,drilling wells and seismic data,this paper analyzes the overall structural deformation characteristics and structural evolution of each segment in the eastern Kuqa Depression.In conclusion:The eastern part of Kuqa Depression can be divided into Tugeerming segment and Yiqikelike-Yaken segment.The structural style of Tugeerming segment is relatively simple.It is an anticline as a whole,which is controlled by the high angle pre-existing basement fault.The Cenozoic structural deformation is limited in the hanging wall of pre-existing fault,and it has the characteristics of overstep propagation.The high point of anticline migrates northward.The Yiqikelike-Yaken segment is characterized by multiple anticlines,basement-involved deformation behind and thin skin detachment ahead,delamination deformation and piggyback propagation,indicating that its structural deformation is controlled by the pre-existing fault and the gypsum in the Jidike Formation.The pre-existing faults and the characteristics of gypsum salt deposits are important factors affecting the spatial-temporal differences of structural deformation in the eastern Kuqa Depression.