Coropuna is constructed atop of 14million year old ignimbrites and lava flows of Neogene age. Individual ignimbrites crop out mainly in valleys; on the highlands they are buried beneath more recent volcanic products. The volcanic basement includes the Miocene to Plio-Pleistocene Tacaza, Huaylillas, Sencca and Barroso Formations; the latter formation includes Coropuna itself. Below these formations lie the sedimentary Murco and Socosani formations and the Yura Group, which are sediments of Jurassic-Cretaceous age with intruded plutons of the same age; finally there is a Basal Complex of Precambrian age.