 Subduction of the Nazca Plate beneath the South America plate is responsible for most of the volcanism in the Central Volcanic Zone . After activity in the western Maricunga Belt volcanic arc ceased six million years ago , volcanism started up in the Incapillo region , forming the high volcanoes Monte Pissis , Cerro Bonete Chico and Sierra de Veladero . Later , a number of lava domes formed between these volcanoes . 
