:''Atacama redirects here; for the political-administrative region of [[Chile]], see'' [[Atacama Region]].
[[Image:Atacama1.jpg|300px|right|thumb|Atacama Desert]]
The '''Atacama [[Desert]]''' is a virtually rainless [[plateau]] in [[South America]], extending 966 km (600 mi) between the [[Andes]] mountains and the [[Pacific Ocean]]. It is created by the [[rain shadow]] of the Andes east of the desert. Its area is 181,300 square kilometers (70,000 mi²)<ref name=nyt>{{cite book | first=John W. (ed.) | last=Wright | coauthors=Editors and reporters of ''The New York Times'' | year=2006 | title=The New York Times Almanac | edition=2007 | publisher=Penguin Books | location=New York, New York | id=ISBN 0-14-303820-6 | pages=456}}</ref>, in northern [[Chile]]. It is made up of [[salt]] basins (''salares''), sand and [[lava]] flows, and is 15 million years old and 100 times more arid than [[California]]'s [[Death Valley]].
[[Image:Valle de la luna san pedro chile.jpg|thumb|300px|Scene from Valle de la Luna (Moon Valley) near San Pedro de Atacama.]]
==Driest desert==
The Atacama Desert is ''the'' driest places on [[Earth]], and is virtually sterile because it is blocked from moisture on both sides by the Andes mountains and by coastal mountains. The average rainfall in the Chilean region of [[Antofagasta (region)|Antofagasta]] is just 1 mm per year. Some weather stations in the Atacama have never received rain. Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971.<ref name=nyt/> It is so arid that mountains that reach as high as 6,885 metres (22,590 feet) are completely free of [[glacier]]s and, in the southern part from 25°S to 27°S, may have been glacier-free throughout the [[Quaternary]] — though [[permafrost]] extends down to an altitude of 4,400 metres and is continuous above 5,600 metres. Studies by a group of British scientists have suggested that some river beds have been dry for 120,000 years.
Some locations in the Atacama do receive a marine [[fog]] known locally as the ''Camanchaca'', providing sufficient moisture for hypolithic [[algae]], [[lichen]]s and even some [[cactus|cacti]]. But in the region that is in the "fog shadow" of the high coastal crest-line, which averages 3,000 m height for about 100 km south of Antofagasta, the soil has been compared to that of [[Mars (planet)|Mars]]. Due to its otherworldly appearance, the Atacama has been used as a location for filming Mars scenes, most notably in the television series ''[[Space Odyssey: Voyage to the Planets]]''.
[[Image:Chile-Atacama.jpg|thumb|left|Atacama road.|220px]]
In 2003, a team of researchers published a report in [[Science magazine|''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 and is being used by [[NASA]] to test instruments for future Mars missions. [[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).
==Human occupation==
The Atacama is sparsely populated. In an [[oasis]], in the middle of the desert, at about 2000 meters elevation, lies the village of [[San Pedro de Atacama]]. Its church was built by the [[Spain|Spanish]] in 1577. In pre-hispanic times, before the [[Inca]] empire, the super-arid interior was inhabited mainly by the [[Atacameño]] tribe. It is most notable for the construction of fortified towns called ''pucara(s)'', one of which can be seen a few miles from San Pedro de Atacama.
During the 16th, 17th and 18th centuries when under the [[Spanish Empire]] towns grew along the coast shipping ports for [[silver]] produced in [[Potosí]] and other mines.
During the 19th century the desert came under control of Bolivia, Chile and Peru and soon became a conflictive zone due to unclear borders and the discovery of [[nitrate]] there. After the [[War of the Pacific]] in which Chile annexed most of the desert, cities in the zone grew into big international ports, and many Chilean workers migrated there.
The [[Escondida Mine]] and [[Chuquicamata]] are also located within the Atacama Desert.
The [[Pan-American Highway]] runs through the Atacama in a north-south trajectory.
Because of its high altitude, nearly non-existent cloud cover, and lack of light pollution and radio interference from the very widely spaced cities, the desert is one of the best places in the world to conduct astronomical observations. The [[European Southern Observatory]] operates two major [[observatory|observatories]] in the Atacama:
* The [[La Silla Observatory]]
* The [[Paranal Observatory]], which includes the [[Very Large Telescope]].
A new [[radio astronomy]] observatory, called [[ALMA]], is being built in the Atacama by astronomers from [[Europe]], [[Japan]], and [[North America]]. Another radio astronomy observatory, [[Atacama Cosmology Telescope|ACT]], is being built on Cerro Toco in the Atacama Desert.
== Abandoned nitrate mining towns ==
The Atacama has rich deposits of [[copper]] and other [[mineral]]s, 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]] over these resources between Chile and Bolivia began in the 1800s.
Now the desert is littered with approximately 170 abandoned nitrate (or "saltpeter") mining towns, almost all of which were shut down decades after the invention of synthetic nitrate in [[Germany]] at the turn of the 20th century (see [[Haber Process]]).{{Fact|date=April 2007}} The towns include [[Chacabuco]], [[Humberstone and Santa Laura Saltpeter Works|Humberstone, Santa Laura]], Pedro de Valdivia, Puelma, Maria Elena and Oficina Anita.
One of the best examples of an abandoned mining town is that of Baquedano, which is home to one of the most technologically advanced train stations during the nitrate "white gold" boom of the early 20th century. While it is now almost completely abandoned, the remains of the station are untouched and seldom visited by outsiders. Only a few kilometers from Baquedano, on the Pan-American highway, is one of many makeshift cemeteries housing the remains of indigenous miners who were persuaded to work for the German mining operations. Within the confines of the cemetery walls one can judge for themselves just how humane these operations were. Many of the graves belong to children under the age of five, poisoned by the pollution kicked up during the mining process. Fifty years of wind erosion has made this site not for the faint of heart.
==Legends==
* [[Alicanto]]
* [[Yastay]]
* [[Atacama Giant]]
==Notes ==
{{reflist}}
==References==
* [[Fernand Braudel|Braudel, Fernand]], ''The Perspective of the World,'' ISBN 0520081161, vol. III of ''Civilization and Capitalism'' 1984 (originally published in French, 1979).
* [[Lake Sagaris|Sagaris, Lake]]. ''Bone and dream : into the world's driest desert''. 1st ed. -- Toronto : A.A. Knopf Canada, c2000. ISBN 0676972233
==See also==
* [[Atacama Crossing]]
* [[Atacama border dispute]]
* [[List of deserts by area]]
==External links==
*[http://www.sanpedrodeatacama.org SanPedrodeAtacama.Net & Org]
* [http://amesnews.arc.nasa.gov/releases/2003/03_87AR.html News article on "Mars-like Soils in the Atacama Desert, Chile, and the Dry Limit of Microbial Life"]
* [http://magma.nationalgeographic.com/ngm/0308/feature3/ National Geographic feature about Atacama]
* [http://science.slashdot.org/science/05/03/19/1943236.shtml?tid=216&tid=191&tid=14 Autonomous Robot Finds Life in Atacama Desert]
* [http://news.bbc.co.uk/1/hi/sci/tech/4437153.stm Atacama's Super-Dry History]
* [http://www.sanpedrochile.com/ Web Site of the San Pedro de Atacama]
* [http://www.atacamaphoto.com/atacama/atacama-3.htm Atacama Photo Gallery] - incredible images of Atacama landscapes, flora and fauna
{{Deserts}}
[[Category:Deserts of Chile]]
[[Category:Deserts and xeric shrublands]]
[[Category:Neotropic]]
[[Category:Ecoregions]]
[[Category:Ecoregions in Chile]]
[[Category:Global 200 ecoregions]]
[[Category:Plateaus]]
[[Category:Regions of South America]]
[[Category:Ergs]]
[[Category:Physiographic sections]]
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