Where is the World’s Largest Salt Flat?

Caitlin Dempsey

Updated:

Measuring an area of 10,582 square kilometers (4,086 sq mi), Salar de Uyuni in Bolivia, is the largest salt flat in the world. 

Salar de Uyuni lies at the southern end of the Altiplano which is a high plain of inland drainage in the central Andes. Salar comes from the Spanish word for salt and Uyuni originates from the Aymara language (spoken in the Andes) and means a pen (enclosure);

About 40,000 years ago, this area was a large prehistoric lake called Lago Michin which eventually dried out about 15,000 to 10,000 years ago; the dissolved minerals within its waters left the enormous salt flat.  The surface of the Uyuni salt plain contains gypsum (calcium sulfate) and halite (sodium chloride).

An oblique view of a large salt flat and mountains from space.
Salar de Uyuni as seen from the International Space Station on March 17, 2019. Image: NASA, public domain.

Topography of Salar de Uyuni

The Salar de Uyuni is very flat, with a surface elevation variation of less than one meter.  In contrast, the surrounding terrain is very mountainous including the volcanoes of the Andes mountains forming part of the Pacific Ring of Fire.


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Tourists and a tour bus parked on the salt flat. The picture gives an idea of how flat Salar de Uyuni is.
Tourists and a tour bus parked on the salt flat. The picture gives an idea of how flat Salar de Uyuni is. Photo: NASA, public domain.  

Radar Image of Salar de Uyuni

The Sentinel-1A satellite acquired an image of Salar de Uyuni on April 20, 2014.  

This wavy pattern of the image in the area of the salt plain is a result of differing absorption rates from the radar; areas where the radar signal is absorbed appear darker, while areas where the signal is reflected back to the satellite appear lighter.

Radar image of the Salar de Uyuni, Bolivia. Source: ESA.
Radar image of the Salar de Uyuni, Bolivia. Source: ESA.

Lithium mining on the salt flat

Underneath the surface layer of Salar de Uyuni is a mineral-laden brine. This brine contains the world’s largest reservoir of lithium, a prized metal that has numerous industrial uses from creating batteries to creating oven-safe ceramics and glass.

A satellite image showing a large white patch of a salt flat against a earthy background.
January 7, 2019 satellite imagery of lithium mini operations at Salar de Uyuni. Photo: Landsat 8, NASA, public domain.

Found in lithium chloride form, Bolivia has established evaporation pools where pumped brine is funneled. Out in the sunlight, the components of the brine crystalize. After sulfate, postassium, and magnesium are removed from the evaporated brine, the lithium chloride can then be processed into lithium carbonate which can then be commercially sold.

One 2011 source estimated that Salar de Uyuni potentially has 100 million tons of lithium.

References

Friedman-Rudovsky, J. (2011). Dreams of a Lithium Empire. Science334(6058), 896–897. https://doi.org/10.1126/science.334.6058.896

This article was originally written on May 9, 2014 and has since been updated.

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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.