The Serdán-Oriental is a broad closed basin at the eastern end of the Mexican Altiplano with numerous late Pleistocene to Holocene rhyolitic lava domes, tuff cones, tuff rings, lava flows, and scoria cones. The basin, filled by large lakes during the Pleistocene, is bounded by the Cofre de Perote-Orizaba range on the east and Los Humeros caldera to the north. The most prominent features of the volcanic field are the two Las Derrumbadas lava domes surrounded by debris avalanche deposits, and the sharp-peaked Cerro Pizarro lava dome at the northern end of the basin. Several of the tuff rings contain lakes, such as Laguna Atexcac and Laguna Alchichica. A major explosive eruption from a vent inferred to be buried within the basin produced the Quetzalapa Plinian pumice-fall deposit roughly 20,000 years ago.