Cenozoic evolution of the Great Arc of the Caribbean and Lesser Antilles slabs: A perspective from a 3D numerical subduction model

Abstract

The Caribbean Plate features a unique tectonic setting and evolution, controlled by the interaction among Cocos, Nazca, North American, and South American Plates. Presently, the Caribbean Plate experiences active subduction on both lateral sides, along the Middle American Trench to the west and the Lesser Antilles Trench to the east. Subduction along the Great Arc of the Caribbean was active from the Early Cretaceous until the Eocene. In this study, we conducted 3D numerical simulations of subduction tailored to the tectonic evolution of the Caribbean Plate using plate reconstructions as kinematic boundary conditions. This study introduces the first numerical model that spans the complete subduction history of the Lesser Antilles. Our 3D numerical simulations focus on the subduction processes involving the Great Arc of the Caribbean and the Lesser Antilles in the northeastern region of the Caribbean Plate since the onset of the Cenozoic era, incorporating pre-existing slabs from earlier subduction. For the Great Arc of the Caribbean, we observe a west-to-east propagating slab detachment that correlates with the cessation of subduction and arc volcanism. In contrast, in the Lesser Antilles, we detail the slab trajectory at the mantle transition zone-lower mantle boundary, where it stagnates due to the combination of a higher viscosity of the lower mantle and the negative Clapeyron slope of the phase transition from ringwoodite to bridgmanite + ferropericlase. Our findings highlight dynamic mechanisms driving slab flattening and lateral motion, including trench retreat and rollback. Finally, the model predicts the existence of corner flow in the mantle wedge and trench-parallel sub-slab flow, in agreement with observed seismic anisotropy patterns. Our conclusions align with prior research and enhance the understanding of how trench retreat, slab detachment and phase transitions have shaped the evolution of the Great Arc of the Caribbean and Lesser Antilles slabs.