Outcrops in the region range in age from Paleozoic to Holocene. The Purico complex formed on top of older ignimbrites such as the Atana ignimbrite in the south and the Puripicar ignimbrite farther north; the neighbouring La Pacana caldera between 4.5 and 4.1 million years ago erupted some of these ignimbrites including the Atana ignimbrite. Occasionally Purico is considered part of the La Pacana system.