 Mechanistically, the onset of the eruptions has been explained with delamination events during which parts of the lower crust broke off, asthenospheric material replaced the crust lost by delamination and basaltic magmas penetrated the remaining crust.These stages have left an ignimbrite plateau that surrounds the caldera except on its southern side, and which is noticeable on satellite images.It covers a surface area of about and is the largest ignimbrite system in the Puna plateau.