Salar de Uyuni: The Largest Salt Flats on Earth

Antarctica might look somewhat like this at a glance, but it doesn’t have the sheer flatness over an area of 10,000 square kilometers. Perhaps, then, it’s more like an extraterrestrial planet with no people – just a windswept, briny atmosphere, thin in oxygen because of its height. But no – this vast expanse is right here on earth in one of our South American countries, Bolivia. It is Salar de Uyuni, the largest salt flats – and one of the most amazing sights – in the world.

Salar de Uyuni, BoliviaPhoto: Lion Hirth

Millennia ago, about 30,000 years or a little more, there was one big lake, Lake Minchin. It changed through different geological processes and ended up as two freshwater lakes and two saltwater lakes, one of those being Uyuni. As time went by, Uyuni developed a thick salt crust of brine on top composed of lithium, magnesium and table salt.

Today, the salt is scraped up from the sheer flat surface of the flats into piles where it dries better and is easier to cart away. Some of the crust goes down meters into the brine; in other places it is just a few inches, as you can see below.

Half of the world’s lithium in to be found in the brine under Uyuni’s salt flats; this is extracted for use in batteries and medicines. Tourism is also one of Bolivia’s biggest sources of income, and the salt flats are a must stop for most. Tourists get to stay in salt hotels: the first one built closed in 2002 because a few environmental regulations were forgotten – like what to do with waste materials – but others have been opened closer to the edge of the flats where there are roads to cart off the waste. Big blocks of salt became the bedrock of the hotels as this was the most readily available building material around. Below the man is cutting the blocks for construction.

There are also several lakes in the area that flood during the rainy season, sending cascades of water to cover Salar de Uyuni. When it is covered in a sheet of water it becomes the largest mirror in the world!

Salt flats as a mirrorPhoto: Chechevere

Not only does the Salar provide salt, lithium, halide and gypsum, the proceeds of which the locals who pile it up get to divvy up as part of their cooperative; no, astronauts use the flats as well! It is one of the highest and largest flats on earth, and is smoothed from flooding every season – dissolving bumps and interference – so is ideal to use for calibrating the location of satellites.

The sun slowly sets on the flats, the golden colors shimmering back from the ground, making the whole lake look like it has turned into a fairies’ party ground with fairy lights everywhere. It is a remarkable sight that is seen nowhere else in the world, nor probably in the universe.

Sources: 1, 2