Thermal and exhumation history of the Coastal Cordillera arc of northern Chile revealed by thermochronological dating

► Rock samples from a 2 km thick crustal section dated using apatite (U-Th)/He dating. ► Results reveal crustal cooling in the Coastal Cordillera during onset Andean orogeny. ► Two explanations: forearc uplift and erosion, and/or changes in plate subduction. ► Ridge subduction can cause significant crustal cooling by flat slab dewatering. ► Ridge subduction can explain important aspects of development of the Central Andes.