Discovery of a large resurgent caldera at Incahuasi, southern Ayacucho Province, Peru

Abstract

The Central Volcanic Zone (CVZ) of the Andes is well known for its intense silicic volcanism, with emplacement of large-volume plinian fall deposits and ignimbrites in Cenozoic to Quaternary times (de Silva and Francis, 1991). The CVZ hosts a number of silicic calderas (super-volcanoes) that are preserved in nowadays topography or have been inferred from volcanological studies (e.g. calderas concealed beneath younger stratovolcanoes). While source calderas of several CVZ ignimbrites have been identified, many others are still unknown because they experienced later volcanism, fluviatile and glacial erosion, as well as tectonic dismantling. This is the case in Southern Peru where successions of voluminous ignimbrites with unknown sources are exposed in 2–3.5 km-deep canyons of Ica, Ayacucho, Arequipa, and Moquegua provinces (Sébrier and Soler, 1991; Thouret et al., 2007; 2016; Schildgen et al., 2009; de La Rupelle, 2013). In this note we describe for the first time a large resurgent caldera in Southern Ayacucho province, where geothermal and epithermal economic potentials might exist.