CENOZOIC EVOLUTION OF THE NORTHERN CARIBBEAN PLATE BOUNDARY: INSIGHTS FROM THERMOCHRONOMETRIC, KINEMATIC AND GEOMORPHIC DATA

It is widely accepted that the Northern Caribbean plate boundary transitioned from compressional to transcurrent deformation in the Paleogene in response to collision with the Bahamas platform and accompanied by an eastward shift of the locus of subduction. However, the temporal and along-strike spatial onset of this transition, from Cuba to Puerto Rico, remain poorly constrained. The deformational and magmatic history of the island of Hispaniola is key to understanding the plate boundary kinematic transition in the early Eocene (~50 Ma). However, Hispaniola lacks critical constraints on the timing of deformation and exhumation. This study presents new data from zircon and apatite (U-Th)/He analyses from central Hispaniola in the Dominican Republic and constrains the exhumation history of tonalitic plutons in the Cordillera Central. These data are combined with >500 U-series, noble gas, and fission-track compiled ages from across the Greater Antilles to elucidate the locus and timing of this plate-boundary reorganization. We integrate these data with geological and structural field observations and measurements of kinematic indicators, as well as a geomorphic analysis of tectonically influenced channel steepness and concavity, and knickpoint migration in the Cordillera Central and Cordillera Septentrional. These data provide critical new insights into the timing and kinematics of plate-boundary deformation in Hispaniola and their connection to exhumation along faults bounding the Cordilleras, and at the broader scale, the timing of plate reorganization within the geodynamic framework of the Northern Caribbean Plate Boundary.