Scientists have unraveled the mystery of the mysterious “honeycomb” patterns found in salt deserts around the world.
These places are some of the most extreme and inhospitable places on Earth, and their bizarre polygonal structures attract hundreds of thousands of tourists every year.
Salt deserts can be found in areas such as the Badwater Basin in Death Valley, California and the Salar de Uyuni in Chile.
A new study suggests that the shape and size of the “honeycomb” pattern is caused by the movement of salt water (with a high concentration of dissolved salt) in the soil below the surface.
The constant size of the elements and the growth rate of the patterns could also be related to this, say scientists from the University of Nottingham Trent and Graz University of Technology in Austria.
It was previously believed that the salt crust in the desert dries up and forms cracks around which “honeycomb” patterns grow.
Other scientists have also suggested that the salt crust is constantly growing and bending due to lack of space, forming indistinct patterns.
However, none of the theories explains the fixed size of the “honeycomb” shape, which always ranges from one to two meters.
Dr Lucas Gehring, Associate Professor at the School of Science and Technology at the University of Nottingham Trent, said: “In the salt flats, the first and almost the only thing you see is an endless jumble of ordered hexagons and other shapes. patterns on the surface reflect the slow rise of salt water. “In soil, the phenomenon is a bit like convection cells forming in a thin layer of boiling water. Despite their beauty, winds blowing over salt marshes are the main source of atmospheric dust, and our results will help to understand such processes in desert conditions.”
The scientists conducted lab experiments to see how salt water moves in sandy soil and analyzed patterns under various conditions.
And in two field studies in California, scientists observed patterns in nature and collected samples to show that currents within the Earth reflect patterns seen on the surface.
The salt flats in which these patterns occur are not dry, and very saline groundwater often reaches and sinks directly under the salt crust.
Although this water could be quickly accessed by digging it by hand, it would be too salty to drink.
When this brine evaporates under the hot summer sun, the salt remains, making the groundwater directly below the surface more saline and therefore heavier than the fresh water lurking below.
If this difference in salinity is large enough, salt water near the surface begins to sink down, while fresh water rises from below.
The study suggests that when convective ridges develop next to each other in the Earth, they shrink together and form hexagonal “honeycomb” patterns along the edges that dunk the brine.
And when there is a particularly high percentage of salt, salt also crystallizes on the surface. Over time, the resulting crust forms raised humps and edges that create a “honeycomb” pattern.
The study, which involved the Max Planck Institute for Dynamics and Self-Organization, the University of Southampton, the University of Leeds, the University of Gotting and the University of Oxford, is published in Physical Review X.