When it comes to flatness on Earth, the surface of a calm lake is probably the optimal setting. You can witness the scene, and paddle a canoe across it, but you can’t go for a walk on it. Many landscapes in the Plains States or in Australia’s interior, or the deserts of Ethiopia, among others, feature some vast stretches of planar terrain, but on many of these there are small undulations, or at least vegetation to create some texture on the ground. It may be that the largest flat expanses on the planet are completely out of sight, on the abyssal plains of the deep sea. Once again, these are places far too difficult to walk upon, and there’s all that crushing water pressure, too. So moving back to land, it seems the flattest places are actually lakes or landlocked seas…that have dried up. As their waters evaporated, copious amounts of dissolved salts were laid down to create a very flat, hard surface, where nothing can grow. These salt flats are usually in desolate and remote desert areas, given the climate needed to dry up a lake.
The largest example of this kind of landform is in southwestern Bolivia, near the border with Chile, and just north of Argentina. Surrounded by the Andes, at an elevation of nearly 12,000 feet, is el Salar de Uyuni. At over 4,600 square miles, this salt flat it is truly vast. So big, in fact, that it is said you can see the curvature of the Earth at the horizon, which goes to show that there really is no truly flat surface on the planet. The Salar’s surface alternates between being a hard, dry crust patterned with millions of hexagonal shapes, to a shimmering pool of brine in the rainy season. Falling rainwater and overflow from other, more watery lakes nearby spread liquid across the salt flat to a depth of less than a couple of feet at the deepest. When the dry season pulls the water away, the salt surface, dissolved and freshly smoothed, is enhanced with another thin layer of deposited minerals, and blindingly white. The expanse of salt is so huge that it is easily visible from space. Its flatness is so uniform that NASA satellites bounce signals off its surface in order to calibrate their orbital height. On the ground, the vistas that the salt pan provides are themselves otherworldly. The horizon seems to go on forever, and when the rains add a mirror-like coating to the surface, objects appear to stand on water or be suspended in air. The wide, flat expanse can also make for some clever photographic tricks because of the lack of distant objects that might otherwise provide perspective.
It takes some effort to reach the Salar de Uyuni, given its remoteness and elevation. Tourism though, does a brisk business with those who don’t mind struggling a bit to witness nature’s more spectacular vistas. Requiring less arduous travel is the biggest example of horizontal-salt-for-days in the U.S., the Bonneville Salt Flats of Utah. The remnants of ancient lakes west of the Great Salt Lake, the flats are crossed by Interstate 80 and have been used as a testing grounds for high-speed vehicles for over a century. It’s one of the few places you can go hundreds of miles per hour and not run into bumps, trees, or anything else. There really isn’t much out on a salt flat but salt, and it would seem like adventure tourists would be the only ones who who’d have any interest there. Evaporated lakes however, leave behind more than just table salt. In the case of Bonneville, potash is in the mix. For half a century, mining companies have been drawing off the brine that lies beneath the thick salt crust and drying it out in ponds to obtain the potash. This process, though, robs the salt pan of its supply line. The thickness of the salt, once up to 5 feet at its deepest, now is measured in inches. A number of years ago, the mining companies agreed to replenish the thinning surface. After all, that potash-stripped salt was stacking up in massive piles around their operations. What better way to get rid of it than to make a slurry of it and pump it back onto the flats to re-build the surface? The operation has been somewhat successful in halting the degradation, but has not significantly thickened the salt layer. Racing enthusiasts wonder how much longer the storied location can be used to test vehicles.
At the Salar de Uyuni, a similar kind of interest threatens the spare landscape. Uyuni’s salt carries an element that the world is finding ever more desirable. The prize is lithium, a key ingredient in batteries and electronic devices that grow in importance daily. Australia is the biggest producer of lithium, but Chile and Argentina follow right behind, and Bolivia is keen to develop its stores as part of South America’s “Lithium Triangle.” Parts of the Salar de Uyuni, rather than being featurelessly flat, are punctuated by scores of salt piles raked up by locals, ready to be hauled away to sell as salt. Industrial mining could have a much greater impact on the area, both visually and environmentally. Each season’s rains bring in more dissolved salts and their chemicals from the surrounding mountains and nearby lakes, adding to the brine layer beneath the hard salt. But extraction may come to exceed input as electric cars and a myriad of electronic gadgets demand more and more of the essential element. This brings a flow of wealth to mining companies, but local tourism businesses worry about their long-term effects on the salt flat, and its solitude. So far, lithium mining operations there are small and exploratory, and the size of the world’s biggest salt pan has been compared to the size of Jamaica, with a salt thickness of over 30 feet at its center. There is a lot of salt and room out there, so there may be space enough for both endeavors. Industry, though, has a way of exploding if its product proves lucrative. It remains to be seen if the enchanted, silent moonscape of the Salar de Uyuni will be able to withstand the hunger of modern plugged-in society.
All this talk of salt got you thirsty for an adventure? Head off to Bolivia and check out those crazy salt flats! Let Nelles guide you, with their travel map of Bolivia and Paraguay, available from Maps.com.
caption: The interior draining watershed that includes the Salar de Uyuni.
source: Wikimedia Commons: Sayri (Public domain)
caption: As the water dries up each season, hexagonal ridge patterns develop on the salt flat.
source: Flickr: Dimitry B. (CC by 2.0)
caption: The reflective surface of the shallow flooding on the flats makes for dreamlike images.
source: Wikimedia Commons: Chechevere (CC by 3.0 Unported)
caption: Cones of drying salt scraped up by local salt merchants add a little texture to the flats.
source: Wikimedia Commons: Ricampelo (CC by 3.0 Unported)
caption: Hotel building made of salt blocks cut from the surface.
source: Flickr: Pedro Szekely (CC by 2.0)
caption: Cars have been going fast at Bonneville Salt Flats for a long time, but their former 13-mile run has been reduced by more than a third after decades of potash mining.
source: Pixabay: valorcsr (CC0)
caption: The almost featureless distant horizon of the Salar allows for fun with perspective.
source: Wikimedia Commons: Chris Feser (CC by 2.0)
caption: Salar de Uyuni even has flamingoes!
source: Wikimedia Commons: Luca Galuzzi – www.galuzzi.it (CC by SA 2.5)