Three stages of plateau evolution manifested in present-day Tibetan Plateau.

Abstract

Notwithstanding the evolution of the Tibetan Plateau being a fundamental topic in continental dynamics, general mechanisms of Plateau uplift remain elusive and past Plateau evolution models lack clarity of the actual geodynamical process. Here, with detailed mappings of intra-crustal low-velocity zones and crust-mantle discontinuity in the region using the seismic data consolidated by the China Seismological Reference Model project, we show that the present-day Tibetan Plateau manifests three stages of mid-crustal flow driven evolution that can be clearly identified in three distinct regions of the Plateau: a pre-response stage with a young mid-crustal partially molten zone but little response of surface topography and crust-mantle discontinuity, the first stage with a mature mid-crustal partially molten zone by deepening crust-mantle discontinuity without large-scale surface uplift, and the last stage by large-scale surface uplifting. Our results provide direct observation and a unique reference of geodynamical responses at different evolution stages of the continent-continent collision zones.