Structural geology, deformation history, and tectonic evolution of the Eastern Tibetan Plateau

This study examines the structural geology, uplift history, and tectonic evolution of the eastern Tibetan Plateau, a crucial natural laboratory for assessing how continents deform in response to the far-field effects of the Cenozoic India–Asia collision. Although this plateau margin is central to models of collisional orogenesis, the mechanisms and partitioning of deformation that drive uplift remain debated, in part because surface constraints have been limited by the scarcity of systematic geologic mapping—an issue underscored by recent large earthquakes that ruptured previously unmapped faults. To address these gaps, we integrate new geologic mapping across ~30,000 km² with interpretations of seismic reflection profiles to build balanced cross sections, kinematic reconstructions, and tectonic maps that quantify shortening and fault architecture in the Longmen Shan, Min Shan, and the adjacent Songpan–Ganzi terrane. These data reveal (1) pronounced along‑strike variability in the style, timing, and magnitude of shortening within the Longmen Shan; (2) a previously unrecognized, crustal‑scale tectonic wedge beneath the Min Shan that provides a viable mechanism for uplift not explained by range‑bounding structures alone; and (3) a regionally distributed conjugate strike‑slip fault system that helps accommodate and partition deformation across eastern Tibet. Together, these results are synthesized into a three-dimensional tectonic framework that links active deformation, surface uplift, and basin evolution, and they help resolve long-standing regional puzzles, including high topography despite low geodetic slip rates and limited Cenozoic foreland basin development along the plateau margin. In parallel, we combine detailed field observations with systematic low‑temperature thermochronology to reconstruct tempo-spatially variable uplift and erosion histories along the eastern plateau margin. Thermochronologic patterns indicate that the central Longmen Shan has experienced persistently rapid uplift and erosion since ca. 40 Ma, defining a NE–SW‑oriented rapid exhumation zone consistent with long‑lived, channel‑flow–influenced deformation. The northern Longmen Shan records more regional cooling compatible with fault‑controlled uplift from ca. 40-20 Ma. Since ca. 10 Ma, pronounced regional cooling in the middle segment between the Longriba and Anxian–Guanxian faults indicates episodes of accelerated uplift and denudation, whereas the northern segment shows mainly localized uplift near specific faults. Overall, the results favor a modified thrust‑dominated model incorporating wedge and duplex development, while also documenting pre‑Cenozoic shortening and along‑strike structural transitions not captured by prior end-member hypotheses. By synthesizing newly mapped and previously identified active faults, this work also improves seismic hazard characterization in a region where damaging earthquakes have repeatedly occurred on unmapped structures.