Thermochronological constraints on Cenozoic exhumation along the southern Caribbean: The Santa Marta range, northern Colombia

We applied detrital thermochronometry of modern sediments in a small, high relief mountain range in the Caribbean of northern Colombia, the Santa Marta range (SM), in order to study the patterns of Cenozoic mountain building. New AFT and U-Th/He data from river sand samples of eight catchments draining the eastern flank of the range together with a compilation of published ages and thermokinematic modeling reveal episodic exhumation with decreasing rates to the SE, away from the Caribbean-South American plate boundary. Paleocene-Eocene (60–45 Ma) exhumation is associated with collision of oceanic crust along western Colombia; a late Oligocene-Miocene (30–20 Ma) episode is associated to opening of the Lower Magdalena Valley, and a late pulse at the middle Miocene (16–10 Ma) relates to forward propagation of the deformation toward the Cesar Ranchería basins and the Perijá range, possibly associated to flat subduction. Exhumation rates derived from thermokinematic modeling suggest a post-Miocene acceleration of exhumation.