Cordillera the cordilleras in Ecuador, Peru, Bolivia, Chile, and Argentina. Mountain ranges of this type have a complex structure, usually the result of folding and faulting accompanied by volcanic activity. In South America the ranges include numerous volcanic peaks. (Though not itself a volcano, Argentina's Mt. Aconcagua, at 22,834 feet (6,960 metres) high, is the highest point in the Western Hemisphere. The Andes cordillera has Ojos del Salado, the highest active volcano in the world, and second highest point in the Western Hemisphere. A number of the volcanoes have been active in historic times. Aside from the volcanic peaks, the crests
Ojos del Salado reports indicate the absence of glaciers on Ojos del Salado. Permafrost exists on the mountain and its melting nourishes several lakes; one lake fed by a creek lies at altitude. Ojos del Salado is an active volcano, but the question of whether it should be considered "currently" (or "historically") active is arguable. According to the Smithsonian Institution's Global Volcanism Program, the most recent known eruption was about 1,300 years ago, with a large margin of uncertainty. However, there is also some evidence for a minor ash emission in 1993, which would definitely qualify the volcano as historically active. The presence