Horcones and Cerro Aconcagua

With a summit elevation of 6962 m, Cerro Acocagua is the highest peak of the Andes - and also worldwide except for Asia. Located at approx. 32° Southern latitude, it is at a similar position as the Himalayas on the Northern Hemisphere. Even though the Aconcagua has a volcanic structure in its interior, it is - in contrast to many other mountains in the Andes - not a volcano. This can be explained by the following theory: the subduction angle at which the oceanic Nazca Plate is pushed beneath the continental South American Plate is relatively flat in this area, which does not favour volcanic activity. In the early stages of evolution of the mountain, the subduction angle was still steeper, so that today's Aconcagua was a volcano at the beginning. Therefore it is characterized by volcanic rocks. Today, the interior structure of the Aconcagua is volcanic, but the mountain is detached from the source of magma. A closer look at the title image reveals a flat, but undulating hilly terrain in the foreground. Now, the question is how this landform could have developed. At least two hypotheses do exist about its formation.