At Copiapo and Jotabeche, the volcanic activity has been subdivided in three phases, the first being the normal volcanic phase, a second phase with a drop in magma supply and the formation of more differentiated magmas in crustal magma chambers such as rhyolites and at the end the eruption of andesites along fractures. Other volcanoes in the Maricunga belt display different evolutionary processes, probably because of a lesser tectonic influence.