The significance of high planation surfaces in the Andes of Ecuador

A traverse of Ecuador crosses five planated units including two main horsts which constitute the Andean Cordillera. A single surface once extended across all units, and its formation was completed by Early Pliocene times. Vertical uplift occurred mainly in the Plio-Pleistocene. Most rock structures in the Andes result from pre-planation tectonics and have no connection with mountain building. Post-planation vertical uplift created the mountains, and uplift led to gravitational spreading. The causes of stillstand and uplift are debatable but subduction and compression fail to account for the nature, the symmetry and the timing of events in the Ecuadorian Andes