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
Llullaillaco Llullaillaco Llullaillaco () is a dormant stratovolcano at the border of Argentina (Salta Province) and Chile (Antofagasta Region). It lies in the Puna de Atacama, a region of tall volcanic peaks on a high plateau close to the Atacama Desert, one of the driest places in the world. It is the second highest active volcano in the world after Ojos del Salado. Llullaillaco formed during two different phases in the Pleistocene-Holocene out of dacitic lava flows. The oldest rocks are about 1.5 million years old. About 150,000 years ago, the volcano's southeastern flank collapse, generating a debris avalanche that reached