Some desert landscapes are covered with salt because the extremely arid climatic conditions cause significant evaporation of water from the soil, leaving behind deposits of mineral salts.
When water flows through desert regions, it carries with it various mineral salts from the soils and rocks. When it reaches a basin where it can no longer escape, this salt-rich water stagnates under a powerful sun. Obviously, in these hot regions, evaporation is very rapid. And this is where it gets interesting: only pure water evaporates, leaving behind all these dissolved minerals. Little by little, as the water disappears, the salts begin to become more concentrated, forming a salt crust on the surface. In the end, after numerous cycles of evaporation, these layers become quite thick, creating those characteristic vast white expanses sometimes called salt flats.
Salt desert landscapes often originate from salt-rich rocks found underground. When groundwater passes through these rock layers, it dissolves some of the minerals, particularly dissolved salts. The water then rises to the surface through capillarity or emerges in shallow springs in certain areas. Once exposed to the air, the heat and sun of the desert quickly evaporate the water, leaving only these salt crystals accumulated on the surface. The geological structure of the subsoil, such as the presence of millions-of-years-old evaporitic rocks or ancient seabeds rich in salty sediments, plays an essential role in the formation and persistence of these particular landscapes.
The desert climate plays an essential role because it is primarily hot and very dry. This means that the water that accumulates after rare rains or temporary floods disappears very quickly through evaporation. And when the water evaporates, it leaves behind all the dissolved mineral salts, which then begin to crystallize on the parched ground. As rains are rare and there is almost no infiltration, the salt concentration gradually increases, forming the typical white crusts recognizable from afar. Additionally, the alternation between scorching days and cool nights accelerates the evaporation-crystallization cycles, further facilitating the accumulation of salt on the surface. It’s a perfect cocktail for covering certain deserts with a beautiful salty layer.
A closed depression is a kind of natural basin with no access to the sea. The water that accumulates there cannot flow elsewhere and eventually disappears solely through evaporation. And since dissolved salt does not evaporate with the water, it gets trapped, which progressively concentrates the minerals. As a result, salt crystals begin to coat the bottom, gradually forming a true salt crust called a salt crust. The deeper and more enclosed the depression, the more intense the evaporation and the more spectacular the accumulation of salt becomes. These places sometimes turn into impressive salt flats, like the salars of South America or the chotts of North Africa.
The Salar de Uyuni in Bolivia is probably the most famous and largest salt desert in the world. An immense white expanse, formed due to the gradual drying of prehistoric lakes, it is now an impressive tourist site and a major reserve of lithium. In the United States, the Bonneville Salt Flats in Utah are renowned for their flat and smooth surfaces; so flat that high-speed vehicles are even tested there. In Africa, the Chott el-Jérid in Tunisia is a vast, spectacular salt plain where water evaporates quickly, leaving behind visible salt crystals as far as the eye can see. Iran is also home to salt deserts like the Dasht-e Kavir, with its salt marshes showcasing almost artistic patterns caused by the intense evaporation of water under crushing heat.
Some salt deserts are so reflective that they create an optical illusion of a mirage. Distant landscapes seem to float in the air, giving travelers the impression of a vast expanse of nonexistent water.
The Bonneville Salt Flats in the United States is famous for its extreme speed races. Its extraordinarily flat and hard surface allows vehicles to reach record speeds, sometimes exceeding 1000 km/h!
The Dead Sea, although not a desert in the strict sense, shares many characteristics with saline desert landscapes. It has such a high salinity that you can float with astonishing ease.
The salt preserved in these deserts may contain valuable clues about our planet's climatic history. Scientists study these formations to better understand past environmental changes and to anticipate future developments.
In some cases, yes. Excessive salinization leads to soil degradation, thereby compromising their fertility and drastically reducing plant and animal biodiversity.
No, some microorganisms, algae, insects, and specifically adapted plants (called halophytes) are able to thrive in these extreme environments, demonstrating an admirable adaptation to very saline conditions.
Primarily, but not exclusively. While common in hot deserts, there are also cold and arid regions such as the Antarctic desert, where salts can also precipitate due to extreme climatic conditions and very slow but constant evaporation.
Yes, absolutely, several salt flats around the world are subject to industrial extraction of salt, lithium, or other minerals, thus contributing to local and global economies.
The desert climate is characterized by low precipitation rates and high evaporation, which leads to the rapid evaporation of surface or groundwater rich in mineral salts and results in the accumulation of salt crystals on the soil surface.
No one has answered this quiz yet, be the first!' :-)
Question 1/5
