At the northwestern end of the India–Asia collision zone, in the eastern Pamir interior, the Kongur Shan extensional system extends for ∼250 km as a composite system of normal faults. As the southernmost segment of the extensional system, the Tashkurgan fault can be divided into a northern and southern segment by the intersection of the Tahman and Tashkurgan faults. To evaluate the tectonic activity along the Tashkurgan fault and explore the extensional characteristics of the southern Kongur Shan extensional system, we integrate geomorphologic analysis with thermochronologic data and modeling. Geomorphic indices, including local relief, normalized channel steepness index (), and river χ-plots, show that the southern Tashkurgan fault is more active than the northern Tashkurgan fault. On the footwall of the northern Tashkurgan fault, most thermochronologic data, which include biotite Ar/Ar (Arbt), zircon (U-Th)/He (ZHe), apatite fission track (AFT), and apatite (U-Th-Sm)/He (AHe) dates, record emplacement-related cooling, and only a few AHe dates possibly record exhumation of <2 km since ∼7 Ma ago. On the footwall of the southern Tashkurgan fault, almost all of the ZHe, AFT, and AHe dates record significant late Miocene to present exhumation; thus, we perform three-dimensional thermokinematic modeling for the normal slip along this fault segment. Modeling results indicate a probably constant slip rate on the southern Tashkurgan fault at a value of 1.4–1.5 mm/a, which corresponds to 6–7 km of both horizontal extension and footwall uplift since 6.5 Ma ago. All together, the geomorphic and thermochronologic evidences imply that the southern Tashkurgan fault is responsible for the ∼E–W extension along the southernmost portion of the Kongur Shan extensional system, while the northern fault segment plays a minor role in the extension. This result, combined with the previously published magnitude of extension along the southern Kongur Shan fault, indicates that the extension at any site along the southern Kongur Shan extensional system can be primarily attributed to normal faulting along a single border fault, which is a typical characteristic of an interbasin transfer zone with a transfer fault.

中文翻译：

---

帕米尔高原东部塔什库尔干正断层的分段：地貌学和热年代学的见解及其对断层滑动转移的影响

在印度-亚洲碰撞带的西北端，帕米尔高原东部，公古尔山伸展系统延伸约 250 公里，是一个正断层复合系统。塔什库尔干断裂作为伸展体系的最南段，以塔合曼断裂和塔什库尔干断裂交汇处可分为北段和南段。为了评估沿塔什库尔干断裂带的构造活动并探索南公古尔山伸展系统的伸展特征，我们将地貌分析与热年代学数据和建模相结合。地貌指数，包括局部起伏、归一化河道陡度指数（）和河流χ图，表明塔什库尔干断裂带南部比塔什库尔干断裂带北部更加活跃。在塔什库尔干断裂北部下盘，大部分热年代学数据包括黑云母 Ar/Ar (Arbt)、锆石 (U-Th)/He (ZHe)、磷灰石裂变径迹 (AFT) 和磷灰石 (U-Th-Sm) )/He (AHe) 日期，记录了与侵位相关的冷却，并且只有少数 AHe 日期可能记录了自 ∼7 Ma 前以来的 <2 公里的剥露。在塔什库尔干断层南部的下盘，几乎所有的 ZHe、AFT 和 AHe 日期都记录了重要的晚中新世至今的折返；因此，我们对沿该断层段的正常滑动进行了三维热运动学建模。模拟结果表明，塔什库尔干断层南部的滑动速率可能恒定为1.4-1.5毫米/年，相当于自6.5 Ma以来水平延伸和下盘隆起6-7公里。总而言之，地貌和热年代学证据表明，塔什库尔干断层南部导致了公古尔山伸展系统最南端的东西向伸展，而北部断层在伸展过程中发挥了次要作用。这一结果，结合之前公布的沿公格尔山断裂带南部的伸展幅度，表明沿公格尔山伸展系的任何地点的伸展都可以主要归因于沿单一边界断裂的正断层作用，这是一个典型的特征具有转换断层的跨流域转换区。