This chain of andesitic-dacitic volcanoes along the Chile-Bolivia border contains at least 10 postglacial centers and stretches from Escalante volcano in the N to Sairecábur volcano in the S. 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 S of the summit, but most recently produced a pristine lava flow to the NW. An active sulfur mine is located N 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. The Pleistocene-Holocene Curinquinca volcano lies at the NE end of the complex; Cerro Colorado volcano lies at the NW end.