Ducks, geese and flamingos frequent waterbodies and salars. La Pacana has erupted two ignimbrites which differ in composition and were emplaced one shortly after the other: The dacitic Atana ignimbrite and the rhyolitic Toconao ignimbrite. The Atana ignimbrite was once considered part of the Guaitiquina ignimbrite, which was later split off, while the Puripicar ignimbrite may be correlated with the Atana instead. Also, some of the ignimbrites erupted by La Pacana originally were attributed to Cerro Guacha. Both ignimbrites originated from different parts of the same magma chamber and their origin in the La Pacana caldera is established by isotope ratios of the rocks and the geographical distribution of their outcrops. Before the eruption of the Toconao and Atana ignimbrites, early activity generated the Pujsa ignimbrite between 5.8 ± 0.1 and 5.7 ± 0.4 million years ago and some stratovolcanoes and porphyries that are cut by the caldera walls. The Pujsa ignimbrite resembles the Atana ignimbrite and like the Toconao ignimbrite is mainly exposed on the western side of the caldera. The first large eruption, which took place between 4 ± 0.9 and 5.3 ± 1.1 million years ago, formed the Toconao ignimbrite. The Toconao ignimbrite crops out mainly west of the caldera; only later were units of the Toconao identified on the eastern side of La Pacana. This ignimbrite has a volume of approximately and is formed by a lower un-indurated and an upper indurated subunit. Tube pumices are contained in the lower subunit and in a less than Plinian deposit that was emplaced beneath the Toconao ignimbrite. The formation of the caldera coincided with the eruption of the Atana ignimbrite; the eruption was still underway when the terrain subsided to a depth of beneath the previous surface in the northwestern segment of La Pacana. Dates obtained on the Atana ignimbrite are between 3.8 ± 0.1 and 4.2 ± 0.1 million years ago, which is not clearly distinguishable from the dates of the Toconao ignimbrite seeing as there is no indication that a pause occurred between the eruption of the two ignimbrites.