 The southern cone developed in several different stages; a first stage generated lava flows emanating from the summit; dating of two such flows has produced ages of 34,000 ± 8,000 and 40,000 ± 3,000 years before present.More than of block-and-ash flows was erupted onto the eastern and western flanks of Ampato, and these flows consist of one andesitic and one dacitic formation; both appear to relate to a lava dome forming stage of volcanic activity.These block-and-ash flows are themselves covered on both the eastern and the western flanks by more thick lava flows, which make up a thick unit and again consist of one andesitic and one dacitic unit; both units appear to have been erupted during the last glacial maximum.