Pastos Grandes was volcanically active for a long time, more than many other Altiplano-Puna volcanic complex centres. Later more recent volcanic centres formed within the caldera, the youngest of these centres are relatively recent Such recent centres close to Pastos Grandes are Cerro Chao and Cerro Chascon-Runtu Jarita complex. The former of which lies on a lineament that appears to coincide with the caldera rim of Pastos Grandes, and the latter seems to rise from the ring fault of Pastos Grandes. but is apparently unrelated to the caldera. Cerro Chascon-Runtu Jarita is less than 100,000 years old according to argon-argon dating. This and ongoing geothermal manifestations suggest that volcanic activity may still occur at Pastos Grandes. Finally, Pastos Grandes and Cerro Guacha may be the heat source for the El Tatio geothermal field west of Pastos Grandes.