Subduction initiation triggered the Caribbean Large Igneous Province

While subduction is known to be the primary driving force of plate tectonics, the mechanisms leading to the formation of new subduction zones remain debated. Here, we use large scale D geodynamic numerical models to simulate the evolution of the Cretaceous Caribbean region, a locus where the eastern Pacific subduction system triggered the formation of a new subduction zone eventually reaching the Atlantic. Our modelling results show how the accretion of the Caribbean old plateau at 135 Ma along the Central American margin triggered subduction initiation of the proto-Caribbean plate and its propagation towards the Atlantic. The simulations reveal how subduction initiationon the back of the accreted old plateau (present-day Central America) at ca. 100 Ma resulted in a major mantle flow reorganizationtriggering a subduction-induced plume. Upwelling of anomalously hot and buoyant mantle resulted in widespread partial melting of the lithosphere and the formation of overthicknened crust reaching up to 21 km, consistent with the 97-70 Ma Caribbean Large Igneous Province.Our modelling results better constrain the mechanism of subduction transfer in the Caribbean region and highlight how subduction initiation induced the formation of the Caribbean Large Igneous Province.