Uplift of the Tibetan Plateau driven by mantle delamination from the overriding plate

Abstract

The geodynamic evolution of the Tibetan Plateau remains highly debated. Any model of its evolution must explain the plateau’s growth as constrained by palaeo-altitude studies, the spatio-temporal distribution of magmatic activity, and the lithospheric mantle removal inferred from seismic velocity anomalies in the underlying mantle. Several conflicting models have been proposed, but none of these explains the first-order topographic, magmatic and seismic features self-consistently. Here we propose and test numerically an evolutionary model of the plateau that involves gradual peeling of the lithospheric mantle from the overriding plate and consequent mantle and crustal melting and uplift. We show that this model successfully reproduces the successive surface uplift of the plateau to more than 4 km above sea level and is consistent with the observed migration of magmatism and geometry of the lithosphere–asthenosphere boundary resulting from subduction of the Indian plate and delamination of the mantle lithosphere of the Eurasian plate. These comparisons indicate that mantle delamination from the overriding plate is the driving force behind the uplift of the Tibetan Plateau and, potentially, orogenic plateaus more generally. Delamination of the lithospheric mantle from the overriding Eurasian plate below the Tibetan Plateau is consistent with topographic, magmatic and seismic observations, according to numerical simulations of the geodynamic evolution of the plateau.