Salado River (Argentina) under the name of Juramento River at the Andes range, from thaw and captured precipitations of the high Acay and Cachi mountains in the Salta Province, near Catamarca Province. The Cabra Corral Dam regulates its flow, and deviates some of it for irrigation. When the river enters the Gran Chaco plains it forms several arms in a broad riverbed only partially occupied. The river then enters the Santiago del Estero Province from the north, near the border with the Tucumán Province, receiving the name of "Salado". The Salado and the Dulce River ("Sweet River") south to it, run diagonally in
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.