Overriding Plate Mantle Delamination Controls the Uplift of the Tibetan Plateau

Abstract The Tibetan Plateau stands as one of the most remarkable and complex topographic features in the world, with its geodynamic origin remaining a highly debated topic. In particular, the challenge lies in how the successive growth of the plateau inferred from paleo-altitude studies is connected to documented spatio-temporally variable magmatic activity as well as to lithospheric mantle removal processes proposed on the basis of the characteristic mantle seismic velocity anomalies under the orogen. Several conflicting geodynamic models have been proposed for this region, but none of them were capable of explaining all these first-order topographic, magmatic and seismic features self-consistently. Here, we propose and test numerically a new evolutionary model of overriding plate delamination and related mantle and crustal melting and uplift events, aiming to reconcile all three main features of the Tibetan Plateau. By comparing the numerical modelling predictions with the observations, we show that the overriding plate delamination model is consistent with the successive northward surface uplift to more than 4 km high. Furthermore, it explains the observed northward migration of magmatism and the observed lithosphere-asthenosphere geometry with the subducting Indian Plate and the delaminating Eurasian mantle lithosphere beneath the area, as imaged by seismic tomography.