DEATH VALLEY, Calif. –It has been a mystery in California’s Death Valley for years.
Massive boulders have been seen out in the midst of a dry lake bed with long trails in the sand behind them as if someone or something is pushing them.
But no one has ever seen what actually is moving these boulders, until now.
Geographer Richard Norris and his team at Scripps Institution of Oceanography say they have solved the mystery of the ‘sailing stones.’
Norris used GPS trackers and cameras around the rocks to record their movement and uncovered evidence that large planes of ice move the rocks as they melt.
In December, the lake bed freezes and on one morning after a rain storm, Norris said, the team saw a thin sheet of ice had formed on the desert surface.
As the sun came up, the ice melted and began to move around atop a film of melted water.
Sheets of ice, some 40 to 50 feet across, moved across the flat surface and moved the rocks, Norris said.
By the end of the day, some of the rocks had moved hundreds of feet. As the day went on, the ice water evaporated leaving the rocks in place and winding trails behind them.
Norris said the combination of rain, freezing temps and a steady wind are rare. He said he was lucky to see it firsthand.
The results of his study are published in the current issue of the journal Plos One.