In addition, the Upper Sencca Ignimbrite, the Lower Sencca Ignimbrite and the Chuquibamba (Huaylillas) Ignimbrite may have originated here as well; the latter was produced by a volcanic explosivity index 7 class super-eruption between 14.3 and 13.2million years ago in the Middle Miocene. The Upper Sencca Ignimbrites are a 2.09-1.76 million years old composite ignimbrite which form a thick apron around Coropuna and other regional volcanoes; Coropuna appears to have formed on top of one of the Upper Sencca Ignimbrite vents.