For the politico-administrative region of Chile, see Atacama (region)

Atacama

The Atacama desert of Chile is a virtually rainless plateau made up of salt basins (salares), sand, and lava flows, extending from the Andes mountains to the Pacific Ocean.

The average width (east-and-west) is less than 160 kilometers (100 miles) but it extends from the Peruvian border 1000 kilometers (600 miles) south to the Bolivian Altiplano. The mountains nearest to the ocean are the Pacific coastal range, with an average elevation of 800 meters (2500 feet). The Cordillera Domeyko , a range of foothills of the Andes Mountains, lies east.

The Atacama Desert is the driest desert of the globe (except perhaps for the McMurdo Dry Valleys in Antartica) and it is virtually sterile because it is blocked from moisture on both sides by the Andes mountains and by coastal mountains. The average rainfall in Antofagasta per annum is just 3mm, and there was a period of time where no rain fell there for 40 years. The Atacama is 15 million years old and 50 times more arid than California's Death Valley. The driest part of the Atacama is an area called the 'double rain shadow.' In 2003 a team of researchers published a report in Science magazine titled "Mars-like Soils in the Atacama Desert, Chile, and the Dry Limit of Microbial Life" in which they duplicated the tests used by the Viking 1 and Viking 2 Mars landers to detect life, and were unable to detect any signs in Atacama Desert soil. The region may be unique on Earth in this regard. Alonso de Ercilla characterized it in La Araucana, published in 1569: "Towards Atacama, near the deserted coast, you see a land without men, where there is not a bird, not a beast, nor a tree, nor any vegetation" (quoted Braudel 1984 p 388).

The Atacama has rich deposits of copper and other minerals, and the world's largest natural supply of sodium nitrate, which was mined on a large scale until the early 1940s. The Atacama border dispute between Chile and Bolivia began in the 1800s over these resources.

The Atacama is inhabited, though sparsely populated. The Pan-American Highway runs through the Atacama. In an oasis, in the middle of the desert, at an altitude of some 2000 meters, is the village of San Pedro de Atacama. Its church was built by the Spanish in 1577, but archeological evidence indicates that the San Pedro area was the center of a Paleolithic civilization that built rock fortresses on the steep mountains encircling the valley. The Escondida Mine and Chuquicamata are also located within the Atacama.

The European Southern Observatory operates two major observatories in the Atacama desert:

• The La Silla Observatory
• The Paranal Observatory, which includes the Very Large Telescope.

External links

• news article on "Mars-like Soils in the Atacama Desert, Chile, and the Dry Limit of Microbial Life"
• National Geographic feature about Atacama
• Autonomous Robot Finds Life in Atacama Desert

Reference

• Braudel, Fernand, The Perspective of the World, vol. III of Civilization and Capitalism 1984 (in French 1979).