Late Miocene extension of the Dali fault system in Southeast Tibet: Coupled tectonic inversion and landscape evolution

作者：Xuwen Shen, Jing Liu‐Zeng, Xiaoming Shen, Kai Cao, Philippe Hervé Leloup, Kexin Qin, Yukun Xing, Jinyang Li, Xianyang Zeng, Heng Wang · 发表于：Geological Society of America Bulletin · 年份：2025 · DOI：10.1130/b38058.1 · 被引用次数：30 · 研究领域：Geological and Geophysical Studies、Geology and Paleoclimatology Research、Geological and Geochemical Analysis

Abstract Tectonic inversion is often a dramatic event with significant implications, yet pinpointing its timing is challenging. The Red River fault, one of the most important high-strain structures in Southeast Tibet, experienced a kinematic reversal, but the exact timing remains debatable. The Dali normal fault system, situated at the northwestern end of the Red River fault, is kinematically linked to the right-lateral Red River fault. This linkage provides an excellent opportunity to unravel the timing of tectonic inversion. The Dali fault system also cuts across the hairpin-shaped reach of the Jinsha River, and its impact on river development would shed light on the landscape evolution influenced by normal faults. This study focuses on the Daju-Lijiang and Chenghai faults, two major branches of the Dali fault system, using zircon fission-track, apatite (U-Th)/He dating, and thermal modeling to reveal rapid exhumation in the footwalls starting at ca. 11–8 Ma and ca. 9–8 Ma, respectively. This shift indicates a tectonic transition from near east–west compression to east–west extension at the end of the Red River fault around the late Miocene (ca. 11–7 Ma), which is also supported by available data in the region. Furthermore, the normal faulting activity along the Daju-Lijiang fault since ca. 11–8 Ma neatly explains spatial and temporal variations in river incision between Tiger Leap Gorge and First Bend, which were influenced by oroclinal bending on the footwall. Tributary r...