Several individual calderas are present within the Frailes plateau, but the most obvious is the Kari-Kari caldera situated on the southeastern edge of the complex (Francis et al., 1981; Schneider, 1987). Previously thought to be an intrusive igneous complex, this 20 Ma old resurgent caldera was the source of the crystal-rich, densely-welded garnet-bearing Kari Kari ignimbrite.
See Frailes Plateau for more information
Francis, P.W., Baker, M.C.W., & Halls, C., 1981. The Kari-Kari caldera, Bolivia and the Cerro Rico Stock. J. Volcanol. Geotherm. Res. v10, p113-124.
Schneider, A. 1987. Eruptive processes, mineralization and isotopic evolution of the Los Frailes, Kari Kari Region, Bolivia. Rev. Geol. de Chile No. 30, p.27-33.