Cerro del León is part of the Central Volcanic Zone, a volcanic belt in the Andes. Volcanic activity occurs since the Oligocene and includes dacitic-rhyolitic ignimbrites. On top of these the main volcanic arc, including andesitic-dacitic stratovolcanoes, has formed away from the Peru-Chile Trench on a crust thick. San Pedro and Lascar have historical activity, but only a few volcanoes have been studied, namely Lascar, Ollagüe and Parinacota.