The Andes are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. Extremely high plateaus surmounted by even higher peaks form a rampart from the southern tip of South America to the continent’s northernmost coast on the Caribbean.
The Andes, or Andean Mountains, are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The Andes consist of a vast series of extremely high plateaus surmounted by even higher peaks that form an unbroken rampart over a distance of some 5,500 mi (8,900 km) — from the southern tip of South America to the continent’s northernmost coast on the Caribbean.
With an average height of about 4,000 m (13,000 ft), the highest is Mount Aconcagua (22,831 ft [6,959 m]) on the border of Argentina and Chile, the Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. The Andes Mountains are the world's highest mountain range outside Asia. The world's highest volcanoes are in the Andes, including Ojos del Salado on the Chile-Argentina border, which rises to 6,893 m (22,615 ft).
Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus – some of which host major cities such as Quito, Bogotá, Arequipa, Medellín, Sucre, Mérida and La Paz. The Altiplano plateau is the world's second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes.
The Andes are also part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that form the western "backbone" of North America, Central America, South America and Antarctica.
The Andes can be divided into three sections:
- The Southern Andes (south of Llullaillaco) in Argentina and Chile;
- The Central Andes in Peru, and Bolivia; and
- The Northern Andes in Venezuela, Colombia and Ecuador.
The Andes are a Mesozoic–Tertiary orogenic belt of mountains along the Pacific Ring of Fire, a zone of volcanic activity that encompasses the Pacific rim of the Americas as well as the Asia-Pacific region. The Andes are the result of tectonic plate processes, caused by the subduction of oceanic crust beneath the South American Plate. It is the result of a convergent plate boundary between the Nazca Plate and the South American Plate The main cause of the rise of the Andes is the compression of the western rim of the South American Plate due to the subduction of the Nazca Plate and the Antarctic Plate.
To the east, the Andes range is bounded by several sedimentary basins, such as Orinoco, Amazon Basin, Madre de Dios and Gran Chaco, that separate the Andes from the ancient cratons in eastern South America. In the south, the Andes share a long boundary with the former Patagonia Terrane. To the west, the Andes end at the Pacific Ocean, although the Peru-Chile trench can be considered their ultimate western limit. From a geographical approach, the Andes are considered to have their western boundaries marked by the appearance of coastal lowlands and a less rugged topography.
The climate in the Andes varies greatly depending on latitude, altitude, and proximity to the sea. Temperature, atmospheric pressure and humidity decrease in higher elevations. The Andes of Chile and Argentina can be divided in two climatic and glaciological zones: the Dry Andes and the Wet Andes. Since the Dry Andes extend from the latitudes of Atacama Desert to the area of Maule River, precipitation is more sporadic and there are strong temperature oscillations.
The Andean region cuts across several natural and floristic regions due to its extension from Caribbean Venezuela to cold, windy and wet Cape Horn passing through the hyperarid Atacama Desert. About 30,000 species of vascular plants live in the Andes, with roughly half being endemic to the region, surpassing the diversity of any other hotspot.
The Andes are rich in fauna: With almost 1,000 species, of which roughly 2/3 are endemic to the region, the Andes are the most important region in the world for amphibians. The diversity of animals in the Andes is high, with almost 600 species of mammals (13% endemic), more than 1,700 species of birds (about 1/3 endemic), more than 600 species of reptile (about 45% endemic), and almost 400 species of fish (about 1/3 endemic).