Salar de Atacama
Salar de Atacama is the largest salt flat in Chile. It is located 55 km (34 mi) south of San Pedro de Atacama, is surrounded by mountains, and has no drainage outlets. In the east it is enclosed by the main chain of the Andes, while to the west lies a secondary mountain range of the Andes called Cordillera de Domeyko. Large volcanoes dominate the landscape, including the Licancabur, Acamarachi, Aguas Calientes and the Láscar. The last is one of the most active volcanoes in Chile. All of them are located along the eastern side of the Salar de Atacama, forming a generally north-south trending line of volcanoes that separate it from smaller endorheic basins.
The salt flat encompasses 3,000 km2 (1,200 sq mi), is about 100 km (62 mi) long and 80 km (50 mi) wide, which makes it the third largest in the world, after Salar de Uyuni in Bolivia (10,582 km2 (4,086 sq mi)). and Salinas Grandes in Argentina (6,000 km2 (2,300 sq mi)). Its average elevation is about 2,300 m above sea level. The topography of the core portion of the salar exhibits a high level of roughness, the result of evaporation and ephemeral surface water, unlike the most other salt flats, as for example the Salar de Uyuni, which is periodically covered with shallow water.
Some areas of the salt flat form part of Los Flamencos National Reserve. The Laguna Cejar is a sink hole lake in the Salar de Atacama, 18 km from San Pedro, Chile. It has a salt concentration that ranges from 5 to 28% (50 to 280 parts per thousand), producing at the higher end of the range an effect of floating like the Dead Sea.
At present the Salar de Atacama depression conforms a subsiding sedimentary basin. Comparing with neighboring areas of the Andes the Salar de Atacama depression is a major topographical anomaly. The Salar de Atacama depression is thought to be caused by a lithospheric block that due to its high density has remained at lower position than the rest of the Andes. The high density would derive from the times the Salar de Atacama depression was a westward rift arm of the Salta Rift Basin located further east in Argentine territory.
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