The beginning of Coropuna's growth has variously been placed over 5million years ago, during the Pliocene or late Miocene, but most of its structure developed during the Quaternary. Volcanic activity has been subdivided into two stages: explosive eruptions during the now mostly eroded Coropuna I stage produced volcanic ash, pyroclastic flows and pumice but also lava flows, while Coropuna II above elevation erupted lava flows from the now snow-covered vents. The existence of a Coropuna III sequence has been proposed. The most recent eruption products have been described as the Andahua Group. About 5.3million years ago, the Sunjillpa volcano was active southwest from Coropuna, while Pumaranra is of Pliocene to Quaternary age.