塔里木盆地库车坳陷中部构造变形样式及分布特征

库车坳陷是塔里木盆地北部一个次级构造单元,受晚新生代陆内造山作用控制,发育典型的挤压冲断构造; 同时,由于古近系和新近系盐层的存在,发育丰富的盐相关构造; 另外,冲断构造各段之间的调节作用还形成了一系列的走滑构造。本文利用最新的2D、3D 地震资料及钻井资料,分析总结了库车坳陷中部的变形样式及分布特征。研究结果表明: 1)根据变形的成因机制,将库车坳陷的构造变形划分为收缩构造、盐构造及走滑构造。2)收缩构造以逆冲断层及褶皱样式为主,盐上构造层可划分为断层相关褶皱和褶皱相关断层,其中断层多在盐层内滑脱。盐下构造层根据断层组合方式可划分为叠瓦状冲断构造、楔形冲断构造及滑脱冲断构造。盐构造可以划分为盐席、盐墙、盐楔入、盐刺穿及盐拱构造。走滑构造在剖面上可见花状构造及不协调变形,平面上则可见雁列褶皱、马尾断层及海豚效应。3)收缩构造及盐构造主要分布于克拉苏构造带及秋里塔格构造带内,自南天山至盆地中心,盐下构造层由叠瓦状冲断构造过渡至滑脱冲断构造,过渡带内则发育楔形冲断构造; 走滑构造集中于坳陷西部的阿瓦特-却勒构造段以及东部的克拉3-东秋8构造段。

The character of deformation style and its distribution law in the middle Part of Kuqa depression,northern margin of Tarim Basin,NW China

Kuqa depression is a secondary tectonic unit of Tarim Basin,which formed typical compressive thrust structures under the action of the intra-continent orogeny in late Cenozoic.It also developed complex salt tectonic because of the evaporite rocks in Paleogene and Neogene and the strike-slip structures in the transfer zone of thrust belt.Based on the new 2D/3D seismic and well data,the research on the deformation style and distribution law in the middle part of Kuqa depression was finished.The result shows that.1)Based on the deformation genetic mechanism,the deformation styles can be divided into three types.They are compression structure,salt structure and strike-slip structure.2)Compression structure mainly performed as thrust and fold,which can be divided into fault-related fold and fold-related fault in overburden of salt layer and imbricate thrust structure,wedge-shape structure and detachment thrust structure in subsalt layer.The fault of overburden of salt layer mainly detachment in salt layer.The salt structure can be divided into salt-sheet,salt-wall,salt-wedge,salt-diapir and salt-arch structure.Strike-slip structure can be found as flower structure and uncoordinated deformation in vertical and en echelon folds,horsetail fault and dolphin structure in the plane.3)Compression structure and salt structure mainly distributed in Kelasu belt and Qiulitage belt.The imbricate thrust structure,wedge-shape structure and detachment thrust structure distributed in subsalt layer from South Tianshan Mountain to the basin.The strike-slip structure can be found in Awate-Quele belt and Kela 3-Dongqiu 8 belt.