The Vilama caldera is the source of the Vilama ignimbrite, which covers a surface of more than and was erupted concurrently with the collapse and formation of the caldera. The eruption occurred between 8.4-8.5 million years ago, but with substantial scatter of the radiometric dates which according to Soler et al. 2007 may be due to excess argon contaminating biotites and thus resulting in spurious age data. Based on the characteristics of the ignimbrite, the eruption was likely triggered by the failure of the magma chamber roof and subsequent onset of vigorous fountaining of ignimbrites through vents formed in the magma chamber roof; similar eruption conditions have been inferred for other Altiplano-Puna ignimbrites.