 A dacitic summit lava dome is not affected by glacial erosion and appears to be the youngest eruption product of Ampato.Early Holocene (11,000 - 8,000 years before present) ash layers in peat bogs around the volcano may have originated either on Ampato or on Sabancaya.Late Holocene tephra layers dated to 1,790 ± 110, 2,050 ± 70 and 4,500 ± 125 likewise may have been erupted from Ampato, but Sabancaya is a more likely source for these ash layers.