Cenozoic tectonic evolution of regional fault systems in the SE Tibetan Plateau

The SE Tibetan Plateau, tectonically situated in the eastern India-Eurasia oblique convergence zone, has experienced multiple stages of deformation since the Cenozoic. Three major tectonic boundaries-the Ailaoshan-Red River, Chongshan-Lincang-Inthanon, and Gaoligong-Mogok shear zones-delineate the first-order tectonic framework in this region. The most striking structural features in the block interiors are a series of NW- and NE-trending fault systems, such as the Dayingjiang, Longlin-Ruili, Nantinghe, Red River, Weixi-Qiaohou, and Lancang-Genma faults, which have conjugate geometric relationships. In this study, we review these structures' geometric and kinematic characteristics and deformation histories. A synthesis of existing geological observations, geomorphological analysis, and chronological data reveal three major Cenozoic tectonothermal events, including crustal shortening, strike-slip shearing, and kinematic reversal. The boundary structures controlled the tectonic extrusion of plateau material during the early Oligocene-early Miocene. In the mid-late Miocene, NW- and NE-trending fault systems mostly experienced diachronous slip-sense inversions. The onset and spatial trend of regional kinematic reversal are constrained by existing chronologic data. Together with geophysical and geodetic observations, the activity and geodynamic drivers of the major fault systems and regional deformation styles are explored, revealing that the SE Tibetan Plateau underwent a transition from discrete (lateral block extrusion) to diffuse deformation in the mid-late Miocene. The intracontinental crustal deformation and its coupling with dynamic processes at depth during the plateau growth are discussed in the context of the India-Eurasia convergence.