Exhumation and Basin Development Related to Formation of the Central Andean Plateau, 21° S

Thermochronological (apatite fission track, AFT) and sedimentological data from the central Andean high plateau and its eastern foreland reflect the Tertiary tectonic evolution of this plateau. AFT data define several stages of exhumational cooling in the plateau and its foreland: A first stage (AFT dates of 40 and 36 Ma), restricted to the central Eastern Cordillera, can be attributed to initial thrusting increments following the Incaic Phase. Around 33–30 Ma, cooling occurred along basement highs over the entire plateau; kinematics were thrusting (eastern Cordillera) as well as normal faulting (Altiplano). From 17 Ma onwards, exhumational cooling took place in the eastern foreland (Interandean-Subandean), reflecting the eastward migration of the thrust front into the Chaco foreland basin.