青藏高原伦坡拉盆地晚期构造变形特征及应力机制分析

Late tectonic deformation characteristics and stress mechanism in Lunpola Basin,Tibet Plateau

以伦坡拉盆地区域二维地震资料解释为基础,提炼出盆地晚期改造主要存在张扭横向调节构造变形、冲断压陷构造变形、推挤褶隆构造变形和压扭隆起构造变形4种构造变形样式,进而将该盆地"南北分带、东西分区"的构造变形格局划分为10个构造变形分区,即:南部冲断带、南部推挤褶隆带、南部压扭隆升带、北部冲断带、北部推挤褶隆带、西部推挤隆升区、西部冲断压陷区、中部横向张扭调节区、东部冲断压陷区和东部推挤隆升区。压性构造样式与张性构造样式共存且统一于左旋斜向对挤的压性应力场,是伦坡拉盆地晚期构造变形的特征。

The 2D seismic data ol the Lunpola Basin showed that the late tectonic deformation ol the basin could be classified into four types： tensional-torsional lateral adjustment, thrust-depression,compressive folding and compressive-torsional uplifting. Ten tectonic deformation partitions were identified ： thrust, compressive folding and compressive-torsional uplifting belts in the south and north, respectively, compressive - torsional uplifting and thrust-depression belts in the west, tensional-torsional lateral adjustment belt in the center,and thrust-de-pression, compressive folding belts in the east. Tensional and compressive structural styles coexist in the Lunpola Basin,and were controlled by the regional sinistral strike-slip compressive stress, which are the most unique characteristics of late tectonic deformation of the basin.