Basaltic and trachyandesitic activity continued after the formation of the caldera. Morphology indicates that the El Rengo and Los Volcanes volcanic cones appear to be of Holocene age, while the Guadaloso vents formed during the Plio-Pleistocene. One age from the eastern side is 148,000 ± 9,000 years ago, it comes from northeast of the Payún Matrú caldera.