Quantitative analysis is crucial for understanding the tectonic evolution of continental-scale shear zones. To unravel the deformation history and processes of a continental strike-slip shear zone, we examined a range of deformed rocks from the Chongshan shear zone (CS-SZ) on the southeast of the Tibetan plateau. The detailed field observations, microstructural, and EBSD texture analyses reveal that the CS-SZ experienced early high-temperature (500–650 °C) deformation overprinted by a low-temperature (300–400 °C) deformation during the shearing and exhumation process. Our vorticity data indicate that the pure shear dominated flow (Wm = 0.32–0.65) of the bulk non-coaxial deformation history overprinted by later increase of simple shear (Wm = 0.68–1) during the later increments of ductile deformation. The bulk strain rates of CS-SZ ranged from 3.9 × 10 to 1.5 × 10 s, while the northernmost region experienced higher differential stress (35 to 81 MPa) and higher strain rates (3.9 × 10 to 2.6 × 10 s). Both sinistral and dextral shear senses occurred in the north segment of CS-SZ, but dextral kinematics was prevalent. The opposing shear senses in the northern segment could be explained by a large amount of pure shear during deformation. The southern segment was dominated by sinistral kinematics. To account for the opposing shear senses in the northern and southern segments of the CS-SZ, we propose a new model called the dextral closing zipper. Geochronology and structural data suggest that the CS-SZ underwent high-temperature ductile deformation beginning at 33–29 Ma and continued until 19 Ma. Subsequently, from 19 Ma to 13 Ma, the shear zone experienced rapid cooling, accompanied by the coeval exhumation of the metamorphic rocks and shearing.

中文翻译：

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青藏高原东南部大陆尺度崇山走滑剪切带的运动学、流变学和冷却


定量分析对于理解大陆尺度剪切带的构造演化至关重要。为了揭示大陆走滑剪切带的变形历史和过程，我们研究了青藏高原东南部崇山剪切带（CS-SZ）的一系列变形岩石。详细的现场观察、微观结构和 EBSD 织构分析表明，CS-SZ 在剪切和折返过程中经历了早期高温（500-650°C）变形，并被低温（300-400°C）变形覆盖。 。我们的涡度数据表明，在延性变形的后期增量过程中，整体非同轴变形历史的纯剪切主导流动（Wm = 0.32–0.65）被后来的简单剪切增加（Wm = 0.68–1）所覆盖。 CS-SZ的体应变率范围为3.9×10至1.5×10 s，而最北地区经历了更高的差应力（35至81 MPa）和更高的应变率（3.9×10至2.6×10 s）。 CS-SZ 北段均出现左旋和右旋切变，但右旋运动最为普遍。北段相反的剪切感可以用变形过程中大量的纯剪切来解释。南段以左旋运动学为主。为了解释 CS-SZ 北部和南部部分相反的剪切感，我们提出了一种称为右旋闭合拉链的新模型。地质年代学和结构数据表明，CS-SZ 从 33–29 Ma 开始经历高温韧性变形，一直持续到 19 Ma。随后，从19 Ma到13 Ma，剪切带经历了快速冷却，伴随着变质岩的同时折返和剪切。