The Cerro Guacha Caldera Complex, SW Bolivia: A Long-Lived, Multicyclic, Resurgent Caldera Complex in the Altiplano-Puna Volcanic Complex of the Central Andes

Measuring ∼50 × 30 km, the Cerro Guacha Caldera Complex (CGCC) is a polycyclic, nested caldera complex within the Altiplano Puna Volcanic Complex (APVC) of the Central Andes. Previous work had established that CGCC was built in three stages. Catastrophic supereruptions of the 1300 km3 (DRE - Dense Rock Equivalent) Guacha ignimbrite at ca. 5.65 Ma and the 800 km3 (DRE) Tara ignimbrite at ca. 3.49 Ma resulted in two nested caldera collapses that define the first two stages (G1C and G2C) of the CGCC. The third stage, G3C, initiated ∼1.8 Ma with the eruption of the Puripica Chico ignimbrite and associated lavas. The only previous detailed systematic study of the CGCC was of the G2C (Grocke et al., 2017a, 2017b). In this work we provide new field, petrochemical and geochronological data on the first and third cycles that now allow us to present the first comprehensive account of the eruption history, as well as the magmatic and volcanological evolution of the CGCC as a long-lived caldera complex.