Mystery Behind the 'Sailing' Stones of Death Valley Unveiled
Scientists have now discovered the mechanism behind the "sailing" stones of Death Valley, which are famous for apparently moving by themselves. They've found that wind from winter storms generate currents that can push the stones over a surface colonized by microbes. Once the water has vanished, the mysterious trail is left on the dry bottom of the lagoon.
For decades, researchers have wondered how the stones seemingly wandered across the desert with no human or animal intervention. Some scientists believe that ice sheets surround the stones during the winter, which aids their movement by the wind. But now, researchers have come up with a different hypothesis.
"Our hypothesis is that they move during the winter, when storms are produced and accompanied by strong winds," said Maria Esther Sanz, one of the researchers, in a news release. "The wind is capable of creating water currents of up to two meters per second, which would be the real cause of the sliding stones."
Altillo Chica lagoon in Spain has a 5 cm layer of water during rainy months. The larger stones stick out and create an obstacle for wind-induced currents. Under these circumstances, the turbulence stirs up the soil around the rocks and creates an initial groove which is the start of a trail that can even move slightly up.
The stones also have help in the form of a microbial community of cyanobacteria, single-celled algae and other tiny microorganisms. This community secretes slippery substances which give the rocks help when sliding across the bottom of the lagoon.
"On the one hand, you can recognize the sedimentary marks or structures which accompany the stone trails and you can observe that they follow the direction of the water currents," said Esther Sanz, one of the researchers, in a news release. "On the other hand, the direction of the trails clearly coincides with the prevailing winds in the area during each storm."
The findings are published in the journal Earth Surface Processes and Landforms.
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