 It has been suggested that a perpendicular chain of volcanoes including Ojos del Salado may be the consequence of the Juan Fernandez Ridge subducting in the Peru-Chile Trench.Volcanism in the area goes back to the Oligocene and Miocene, when the main volcanic arc was located west in the Maricunga Belt.Between 9 and 6 million years ago volcanic activity in the Maricunga Belt decreased and eventually ceased.