Surface Processes driving sHifts in platE tectonic Regimes on Earth

Objective

Earth’s plate tectonics is essential for maintaining long-term habitability. A key challenge is to explain the repeated shifts in tectonic activity during the Wilson cycle, when supercontinents assemble and later break apart. Traditional models focus on deep mantle processes, yet they have not succeeded in reproducing this cyclicity. Growing evidence suggests that climate may also play a decisive role. It has been proposed that A) erosion and the transport of sediments into oceanic trenches can help “lubricate” subduction zones, explaining events such as the acceleration of the India–Himalaya collision or the rapid increase in global plate motions after “Snowball Earth”, and B) the subduction style (stagnant or penetrative) into the lower mantle controls the scale of convection and thus the supercontinent cycle. SPHERE proposes that climate and surface processes may regulate subduction style thus the mantle dynamics, and ultimately, supercontinent cycles, with tropical precipitation gradients acting as a key driver. Yet this link between climate, subduction, and the supercontinent cycle has never been tested. SPHERE (Surface Processes driving sHifts in platE tectonic Regimes on Earth) will establish the first integrated modelling framework that connects surface processes to subduction and mantle dynamics across scales. Building on recent advances in climate-tectonics coupling both in analog and numerical, SPHERE will test three innovative ideas: (1) a self-sustaining cycle between mountain growth, erosion, and subduction behaviour; (2) a climate-driven modulation of global tectonics through tropical erosion and sediment delivery; (3) the tropics acting as a catalyst for supercontinent transitions, influencing mantle circulation and even Earth’s rotation through mass redistribution. By combining analogue experiments, regional simulations, and global-scale spherical models, SPHERE will assess how erosion and sediment transport reshape Earth’s surface and interior. The