Much of the shortening associated with the India‐Eurasia collision has been accommodated by orogen‐spanning shear zones within the fold‐and‐thrust belt that forms the Himalayan orogen. The kinematics on these shear zones and how they accommodated large‐scale displacements remain poorly understood. In general, rock flow has been described as orogen perpendicular towards the south. Here, structural mapping and microstructural analysis are applied to demonstrate that the Darjeeling‐Sikkim section of the Main Central Thrust Zone (MCTZ) records an anticlockwise rotation of the resolved stresses within the orogenic wedge, changing from south to north over the period between 20 and at least 9 Ma. The transport direction during thrusting varies systematically defining broad arcs at the scale of 50 to 100 km, rotating by up to 140° from SE‐ or S‐vergence in the north, to SW‐vergence in the south. This rotation is independent of the ~60‐km‐wide dome in the footwall of the MCTZ, exposed as a broad half‐window. Rotation may have been a response to rheological heterogeneities within the orogeny forming large‐scale flow impediments.

中文翻译：

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印度大吉岭-锡金喜马拉雅山主要中央推力区内的大规模旋转运动

与印度-欧亚大陆碰撞有关的大部分缩短是由形成喜马拉雅造山带的褶皱冲断带内造山带剪切带所引起的。这些剪切带的运动学及其如何适应大规模位移仍知之甚少。通常，岩流被描述为垂直于南方的造山带。在这里，通过结构映射和微观结构分析证明了主要中央逆冲带（MCTZ）的大吉岭-锡金剖面记录了造山楔内已分解应力的逆时针旋转，在20至20年之间从南向北变化。至少9 Ma。推力过程中的运输方向会系统地变化，以50至100 km的范围定义宽弧，从北部的SE-或S-vergence到南部的SW-vergence最多旋转140°。这种旋转与MCTZ底盘中约60公里宽的穹顶无关，呈半透明窗口显示。旋转可能是对造山过程中流变学异质性的一种反应，形成了大规模的流动障碍。