Cerro del Bolsón Cerro del Bolsón Cerro del Bolsón is a mountain in the Aconquija Range of Argentina, in Tucumán province. It is the highest point of a significant eastern spur of the main range of the Andes, east of the Puna de Atacama region. It lies about 200 kilometres east of Ojos del Salado, the highest point in the Puna de Atacama. While not of great height compared to the 6000 metre-plus peaks of the main chain of the Andes to the west, Bolsón is notable for its high topographic prominence (it ranks 69th in the world), resulting from its separation from
Ojos del Salado of fumaroles high on the mountain and recent-looking lava flows, albeit of uncertain age, also argues in favor of a categorization as "active." By these definitions, Ojos del Salado is the highest historically active volcano on Earth. If the older date is accepted, the title of "highest historically active volcano" might reside instead with the somewhat lower Llullaillaco volcano, which certainly has erupted in historic times (most recently in 1877) and is considered active. Salado's rock is predominantly potassium-rich dacite and rhyodacite. Its lavas are high in biotite, hornblende, plagioclase, and opaques, with lower levels of augite, quartz, and hypersthene.