The Andes Mountains of South America represent one of the world’s great mountain ranges.
These mountains form the backbone of South America and stretch more than 8,000 km from the shores of the Caribbean Sea to the ice-fields of Patagonia. Because they run in a north/south direction, there is a large variation in climate ranging from the hot humid tropics through the arid reaches of the high Atacama desert to the cold and wet temperate regions of Tierra del Fuego in the south. The mountains typically are well over 4000 m in height, with about 30 peaks over 6000 m in Chile and more than 100 peaks over 6000 m in the entire mountain range. The Andes are a formidable barrier that dominates the weather of South America.
The principal building era of the Andes Mountains was the Cretaceous period between about 138 million to about 65 million years ago. This mountain building was a result of the Pacific crustal plate slowly sliding under the South American plate, lifting and folding it. These forces continue today and trigger earthquakes and give rise to volcanic eruptions. Much of the range is volcanically active. The principal soils arise from pre-uplift sedimentary deposits and volcanically-derived materials.
The Andes Mountains generally are classified into three zones. The Northern Andes includes areas of Colombia, Venezuela, Ecuador and parts of northern Peru while the Central Andes Mountains cover much of Bolivia and Peru and also northern Argentina and northern Chile. The Southern Andes take in the southern reaches of these mountains in Chile and Argentina to Patagonia. In the entire Andes Range there are about 30,000 species of vascular plants. About one-half of these are endemic to this region.