The Andes of South America represent a relatively new mountainous "backbone", of Cretaceous age that is about 145 million years ago, with a lot of volcanic activity - the highest volcanoes in the world are in the Andes - and many seismic movements -feared by its destructive power- are related to the Andes. The Andes begin in the Northern Hemisphere, at 11° N, in Venezuela. The geological plates of Nazca and Antarctica have a subduction process under the South American plate producing orogenic activity and the rising of the Andes. The Andean mountains can reach almost 7000 m of height in the province of Mendoza, in Argentina. The Aconcagua is the highest mountain in the Southern Hemisphere and the Western Hemisphere. The Andes constitute a barrier to the West or Pacific winds. In this way the Andes influence the climate of many places. In some cases they cause that the rain and the snow fall to their west or to their east but very close to the mountains, leaving extensive regions like the Patagonian steppe, the Cuyo region in Argentina with scarce rain.The Andes and the Humboldt cold Antarctic current also originate the Andean cold desert climate at the Arid Diagonal of South America, which extends from the 13° to 27° S, approximately, where salinas and salares predominate in Bolivia, Chile and Argentina. There are places with rainfall less than 150 mm per year, in the so-called Dry Andes, enclosing regions where there is no rain for years, as in the Atacama Desert. In the Andes there are altiplanos, which are high plateaus. With a height of more than 5000 m the plateaus are very cold and are compared to regions of Mars because they preserve permafrost rich in ground ice, which is a type of permanently frozen ground. The Andes are most varied and complex, with very different characteristics throughout their extension of more than 7000 km in length in South America and their numerous ranges. In the south, the Andes show mountain ranges with very important glaciers or ice caps at low altitude, such as the two Patagonian Ice Fields. In the north however, glaciers appear at high altitude, for example at the impressive mountain Awsanqati in Peru, with more than 6000 m altitude and sacred for the Quechua people. According to their beliefs it is the origin of masculine energy.
Presenter: Dario Trombotto Liaudat