This chain of andesitic-dacitic volcanoes along the Chile-Bolivia border contains at least 10 postglacial centers and stretches from Escalante volcano on the north to Sairecábur volcano on the south. Nomenclature reflecting local usage results in conflicting names applied to these features on Chilean and Bolivian topographic maps. The highest peak, Sairecábur, is located on the northern margin of a 4.5-km-wide caldera. Postglacial activity began south of the summit, but most recently produced a pristine lava flow to the NW. An active sulfur mine is located north of the volcano. Escalante, slightly older than Sairecábur, has a crater lake at its summit and youthful lava flows on its flanks, and other eruptive centers have also produced Holocene lava flows. Curinquinca volcano of Pleistocene-Holocene age lies at the NE end of the complex and Cerro Colorado volcano at the NW end.