Continental-scale shear zones play an important role in accommodating block extrusion and rotation as shown by deformation on the Ailaoshan-Red River shear zone (ASRRSZ) in the SE Tibetan Plateau. This study presents 13 apatite (U-Th)/He, 11 zircon (U-Th)/He, and three apatite fission track dates, together with thermal modeling in the Ailaoshan and Xuelongshan segments (ALSZ and XLSZ) of the shear zone to investigate its Cenozoic exhumation history and mechanism, which are critical for understanding its tectonic and landscape evolution. Our results, combined with published chronologic data, reveal that shear zone rocks along the ALSZ experienced prominent and rapid cooling from high temperature (>500°C) to 120–60°C at a rate of 75–100°C/Myr during 29–17 Ma with northwestward younging onset. A second, lower magnitude accelerated cooling occurred at 14–10 Ma along the ALSZ at a rate of 20–30°C/Myr, with a later initiation on the XLSZ at ~5 Ma and continuing to present with a cooling rate of ~20°C/Myr. Thermal modeling reveals a single rapid cooling phase with a rate of 17–14°C/Myr in the Eocene to early Oligocene for samples outside the shear zones. These three fast cooling episodes are directly related to deformation stages including crustal shortening across the SE plateau, sinistral ductile shearing along the ASRRSZ, and dextral faulting with a dip-slip component on the Red River and Weixi-Qiaohou faults along the shear zone flanks. Furthermore, the northward migration of kinematic reversal and associated cooling along strike since the mid-late Miocene likely reflects the northward advance of the eastern Himalayan syntaxis.

中文翻译：

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哀牢山-红河剪切带新生代剥露：低温热年代学的新见解

青藏高原东南部哀牢山-红河剪切带（ASRRSZ）的变形表明，大陆尺度剪切带在适应块体挤压和旋转方面发挥着重要作用。本研究提供了 13 个磷灰石 (U-Th)/He、11 个锆石 (U-Th)/He 和 3 个磷灰石裂变径迹日期，以及剪切带哀牢山和雪龙山段（ALSZ 和 XLSZ）的热模拟研究其新生代剥落历史和机制，这对于了解其构造和景观演化至关重要。我们的研究结果与已发表的年代数据相结合，表明沿 ALSZ 的剪切带岩石在 29 年期间经历了从高温（>500°C）到 120-60°C 的显着快速冷却，冷却速度为 75-100°C/Myr –17 Ma 向西北年轻化开始。一秒，沿 ALSZ 在 14-10 Ma 处以 20-30°C/Myr 的速率发生较低幅度的加速冷却，随后在 XLSZ 上开始约 5 Ma 并继续以约 20°C/密尔。热模型揭示了剪切带外样品在始新世到渐新世早期的单一快速冷却阶段，其速率为 17-14°C/Myr。这三个快速冷却事件与变形阶段直接相关，包括横跨东南高原的地壳缩短、沿 ASRRSZ 的左旋韧性剪切、红河上具有倾滑成分的右旋断层和沿剪切带侧翼的维西-乔侯断层。此外，自中新世中晚期以来，运动学逆转和相关冷却沿走向的向北迁移可能反映了喜马拉雅东部构造层的向北推进。