The Olca-Paruma complex has been active since 80,000 years before present. Volcan Paruma generated lava flows during the Holocene, and lava flows of Volcan Paruma likewise display a fresh appearance, being clearly post-glacial. Other research has claimed that lava flows on the western side of Olca were erupted during the Pleistocene and that others seem to be much older. The appearance of the edifices suggest that volcanic activity migrated east over time, although validation of the proposed older dates would contradict this. Cerro Paruma is of pre-Holocene age. Potassium-argon dating has yielded ages of 430,000± 500,000 from distal lava flows west of Olca and 5,000± 350,000 from lava flows closer to the summit of Olca on its southwestern slope; both are considered unreliable. More recent volcanic activity was phreatic and phreatomagmatic and formed the summit craters.