Ongoing India–Eurasia collision predominantly driven by Sumatra–Java slab pull

Abstract

Continued India–Eurasia convergence since the early Palaeogene has led to the formation of the Tibetan Plateau. Yet the primary driving mechanisms of this protracted convergence remain debated, limiting our understanding of continental collision dynamics. Here we provide a holistic quantification of various driving forces to this convergence by integrating high-resolution, plate-boundary-resolving global convection models with observational constraints. Whereas different forces can produce the observed plate motion, we show that the primary driving force can be definitively constrained when Indo-Australian intraplate stress and strain rates are used as constraints in addition to plate motions. Specifically, we identify that the position of the transition in stress orientation within the Indo-Australian plate is highly sensitive to the relative strength of plate-boundary forces. When the plate motion and this stress-orientation transition are fit simultaneously, we find slab pull from Sumatra–Java subduction is the predominant driving force of India–Eurasia convergence with continental collision exerting an overall resisting force and rule out mantle basal drag playing more than a secondary role. We suggest slab pull from adjacent subduction zones has been the primary driver of the uplift of the Tibetan Plateau since its onset and so this may be an exceptional event in Earth’s history. The main driving force for the continuing India–Eurasia collision is slab pull from the adjacent Sunda subduction zone, according to global geodynamic simulations constrained by observations including the Indo-Australian intraplate stress distribution.