Western thrusting and uplift in northern Central Andes (western Peruvian margin)

Abstract Tectonostratigraphic revision and a crustal balanced cross-section of the northern Peruvian margin show that the Western Andean Escarpment and the Calipuy Plateau-Basin topographic features are related to a major west-verging basement thrust: the Western Andean Escarpment Thrust (WAET). Thermochronological data through the Coastal Batholith display a regional exhumation since at least 29 Ma and a step-change pattern in the cooling ages that we partly attribute to the WAET activation. Thermal modeling shows higher exhumation rates (~ 170–270 m/Myr) between 12 and 8 Ma, due to the onset of the Nazca Ridge subduction. This regional offshore-onshore study allows as well to unravel the Paleogene-Neogene complex tectonic evolution of the northern Peruvian Andes: (1) a middle Eocene regional erosion (~ 41 Ma) erasing the Incaic orogen nowadays partially preserved in the Western Cordillera and in the offshore Trujillo-Salaverry basins; (2) a late Eocene to early Oligocene postorogenic relaxation and extension (Yaquina and Trujillo basins); (3) the westward WAET propagation and a ~ 150 km eastward jump of the double verging Andean orogen since the late Oligocene.