Volcanic activity after the eruption of the ignimbrite has been subdivided into the older andesitic Purico group and the younger Chascon group. The first includes Cerro Negro, Cerro Purico, Putas and Cerro Toco which assume the structure of polygenetic volcanoes, while the latter is taken to include Aspero, El Cerillo/Chajnantor and El Chascon which are lava dome-lava flow structures. The Chascon group of domes is also the only one which contains mafic xenoliths.