[2] The volcano features are what was once thought to be a caldera, which contributed to the formation of regional ignimbrites of dacitic to rhyolitic composition.
[3] Later it was found that the volcanic complex is better described as a semicircular group of lava domes.
[6] Pairique formed during the late Miocene between 8 and 6.7 million years ago, when volcanism reactivated on the Argentine side of the Puna.
[7] Later dates imply volcanic activity between 11.5 and 10.3 million years ago.
[1] The non-volcanic basement is formed by the Ordovician sediments which crop out in neighbouring mountain ranges, and by the Tertiary Peña Colorada formation.