There are several volcanic units in the Isluga area. A pre-Isluga unit containing Cabay volcano, northeastern Carcanchuni and southern Cerro Blanco are not stratigraphically controlled. The Enquelga unit is the first Isluga unit proper. Further, Isluga and Tata Sabaya and some other volcanoes form a lineament which may coincide with the suture between the Chilenia terrane and the Arequipa-Antofalla block.