Caribbean Plate Boundaries Control on the Tectonic Duality in the Back‐Arc of the Lesser Antilles Subduction Zone During the Eocene

The Eocene tectonic evolution of the easternmost Caribbean Plate (CP) boundary, that is Lesser Antilles subduction zone (LASZ), debated. Recents works shed light on a peculiar period duality in arc/back-arc regions. A compressional-to-transpressional regime occurred north, while rifting and seafloor spreading Grenada basin to south. mechanism for this strong spatial variation its through time has yet be established. Here, using 3-D mechanical models, we evaluate whether change trench-curvature radius at northeast corner CP could have modulated duality. We assume asymmetrical boundaries north (from east west: oblique strike-slip) south (subduction-transform edge propagator-like behavior). Regardless imposed trench curvature, southern half our modeled undergoes NW-to-W-oriented extension due tendency southernmost part South-America oceanic slab rollback. In contrast, depends radius. low promotes transtension-to-transpression, with NE-oriented compressive component principal stress. high largely reduces an extensional similar thus propose initially low-curvature NE-LASZ triggered N-S led ephemeral transpression/compression north. However, additional might been required locally enhance compression.