Sailing rocks are a geological phenomenon where rocks apparently move. This happens rarely and in few parts of the world, like at Little Bonnie Claire Playa in Nevada and the most famous one at Racetrack Playa, situated in the Death Valley National Park, California.
This last owns the biggest number of these rocks and the greatest tracks run by them. The tracks of the rocks are unpredictable, and these events took to several researches led by professors and prospectors since the beginning of 1900. They studied the rocks and monitored their movements, finding no success in great parts of their works about the causes of their movements.
However they found the 3 kinds of minerals these rocks are made of. Little quantitative of them would be made of syenite, an intrusive igneous rock similar to granite. Others are made of dolomite, blu-gray coloured with white bands, but the most common ones are made of black dolomite.
Their tracks can reach sometimes hundreds of metres of length. The average diameter of these stones is around 20 cm long. Rocks slide on the ground, so that when they happen to turn over, changing the bottom side, their tracks look modified. During winter, the land under the rocks ice. With sun, ice breaks up into pieces. The thin floating ice panels make the stones slide on the ground. This is the reason why they seem to float.
Giacomo Trezzi, 2 A Scientifico
