Plume-strengthened crust controlled post-Oligocene deformation partitioning in the southeastern Tibetan Plateau

Abstract Upwelling mantle plumes are recognized to modify the continental lithosphere by building craton-like keels or inducing thermal erosion–related thinning. Such plume-related modification may exert long-term control over subsequent deformation and topographic evolution. In the southeastern Tibetan Plateau (SETP), the late Permian Emeishan large igneous province (ELIP), generated by mantle plume activity, significantly modified the lithospheric architecture in this region. However, current geodynamic models of Cenozoic plateau formation largely neglect the impact of ELIP-related lithospheric modification. Here, we investigated spatial variations in Cenozoic deformation and exhumation across the ELIP’s inner and intermediate zones. These zones span from the plume head to its periphery and are cut by two major Cenozoic faults: the Ailaoshan–Red River (ALS-RR) and Xianshuihe (XSH) faults. Our results reveal minimal post-Oligocene exhumation within the inner zone (0.05–0.15 km/m.y.), in contrast to higher rates in the intermediate zone (0.2–0.3 km/m.y.) and along the ALS-RR (0.4–2.5 km/m.y.) and XSH faults (0.4–0.9 km/m.y.). The limited exhumation corresponds to weak deformation within the inner zone. Integrating geological and geophysical data, we suggest that the late Permian plume activity emplaced voluminous mantle-derived mafic-ultramafic intrusions into the crust beneath the ELIP’s inner zone, increasing crustal rigidity and resistance to Cenozoic deformation and exhumation. Our findings highlight how plume-related lithospheric modification may exert a lasting influence on intraplate deformation, persisting hundreds of millions of years after plume cessation.