Neogene stabilization of the northwestern Tibetan Plateau

The Tibetan Plateau, often referred to as the ‘Roof of the World,’ is the largest and highest orogenic plateau on Earth, shaped by the Cenozoic collision between the Indian and Asian plates. Despite its high-elevation, low-relief topography, the timing and spatial variability of uplift across different regions remain topics of significant debate. Earlier models suggested uniform plateau-wide uplift, but emerging evidence points to diachronous evolution. This study presents the first thermochronological constraints on the tectonic history of the northwestern Tibetan Plateau within the western Songpan-Ganzi terrane, a region previously lacking detailed investigation. Apatite fission track and apatite (U-Th)/He dating of Mesozoic basement rocks from the Hehribaé Tso and Keliya regions identify a phase of moderate to rapid exhumation from the late Eocene to Oligocene, followed by prolonged Neogene tectonic stability. Thermal history modeling indicates that this sector of the plateau reached near-modern topography by the late Oligocene, earlier than the Hoh-Xil region to the east, where uplift persisted into the Miocene. This asynchrony highlights spatially heterogeneous plateau growth, challenging the notion of uniform uplift and emphasizing the role of localized tectonic processes in plateau evolution. The findings refine models of continental deformation and plateau stabilization, offering new insights into the mechanisms controlling orogenic plateau dynamics.