Abstract: Based on structural geometries, kinematic observations, and sand-box simulation results, the new interpretation explains that the Bachu fold belt in the Tarim basin is composed of detachment folds flanked by various-scale kink bands primarily unassociated with faulting. The Bachu antiform belt is characterized by the detachment fold. The detachment fold crests are bounded by kink bands, which are narrow zones of angularly folded strata. The substantial width of these kink bands, their sub-parallel edges in the outcrop cross-sections, and their orientation at a high angle to layering, as well as their organized spacing and conjugate geometry, support a kink-band interpretation. Application of sandbox models for tectonic simulate modeling regenerates kink-band development and evolution: wide-gentle detachment folding → tight detachment folding → fold pop-up → fault adjusting. The analog results strongly support that the kink-band is one of the structure types to form the Bachu fold zone.

Key words: Bachu fold belt, geometric, kink band, fault, simulate experiment

摘要： 基于精细的构造几何学和运动学观测, 结合砂箱模拟实验结果分析, 将塔里木盆地巴楚褶皱带解释为不同规模膝褶带形成的大型背斜构造, 与断裂作用无关。新解释强调巴楚褶皱带为膝褶型背斜变形, 系膝褶带围限而形成的褶皱。该类型构造具有如下几何学特征: 带内地层发生一定角度的倾斜, 具有一定宽度, 膝褶带两侧边界近于平行, 膝褶带与带外地层呈高角度关系, 部分膝褶带呈共轭出现。砂箱模拟实验重现了盆地腹地膝褶带发育和演化的全过程: 宽缓拆离褶皱→紧闭拆离褶皱→褶皱突起→断层调节改造作用, 模拟结果证明膝褶带是巴楚隆起形成过程的重要构造要素之一。

关键词: 巴楚褶皱带, 几何学, 膝褶带, 断层, 模拟实验