Scientists Finally Reveal Why Honeycomb Patterns Are Forming in California’s Salt Desert
Salt deserts are a mesmerizing sight, almost otherworldly. The vast areas of land with riddles of hexagonal patterns of encrusted salt attract tourists, be it the Great Rann of Kutch in India– the largest salt desert in the world, or the Badwater Basin in California’s Death Valley. Intrigued by the salty hexagons, scientists have been long trying to solve the mystery of what caused them. Previously, it was theorized that the cracks and ridges take formation into geometric patterns by bending and fragmentation under strain as the salt crust expands and dries out. But that theory was debunked recently as new studies suggest that the groundwater beneath the salt surface is fundamental to the process, per a study published in the journal Physical Review X.
"The fantastic landscape demands an explanation. What we've shown is that a simple, plausible explanation is there, but hidden beneath the ground,” said Lucas Goehring, study author and associate professor of physics at Nottingham Trent University in England. Interestingly, the scientists had no defined purpose in mind when researching the subject, besides mere curiosity. Jana Lasser of Graz University of Technology in Austria shared that the phenomenon was a natural puzzle meant to be solved. "Nature presents us with an obvious and fascinating puzzle that stimulates our curiosity and thereby prompts us to solve it — even without any direct further possibility of application in mind," she stated.
The new study explained that the hexagon formation is rooted in thermodynamics. Layers of salty and less salty water circulate in donut-shaped currents and are simultaneously adjoined horizontally giving rise to the 'honeycomb' pattern across vast areas on the salt deserts. The sizes of the hexagons are uniform in every part of the world, ranging between three to six feet. Goehring added that the surface patterns indicate the movement of salty water within the soil.
Moreover, salt deserts can appear deceiving with their seeming dry surfaces as salty water exists just beneath the salt crusts. The water aids in the pattern formation as it evaporates in the summer and leaves salt residues that dissolve further into the next layer of soil. The saltwater sinks into the ring of fresh, less salty water under the soil causing the latter to rise to the surface and eventually evaporate once again leaving the salt residues. This cycle of salt water seeping into layers of soil while the freshwater evaporates is called a convection roll, as per the study.
"It is well known that hexagonal patterns arise from convection and evaporation processes, [but] this paper connects that with the penetrative convection of the porous layer underneath, which seems very plausible as a wider mechanism driving the whole salt formation,” Scottish researcher Stuart King told Live Science. The researchers elucidated convection rolls typically adopt circular donut shapes but the proximity of several of them packed together allows the formation of honeycomb patterns on salt flats. Earlier studies focused only on one aspect, either subsurface currents or the salt crust. However, researchers now argue that both features are key in shape formation. Salar de Uyuni in Bolivia and the Danakil Desert in Ethiopia are some of the popular salt deserts in the world.