A group of scientists has claimed to have solved the more-than-half-a-century-old mystery behind 'wandering stones' in the Death Valley in California.

The mysterious movement of rocks across the dry ground of the Golden State's Death Valley was first reported in 1948, but no one had documented directly the movement of the rocks until last winter.

Last winter, four scientists tagged 15 limestone slabs with GPS devices in order to track their movement. The rocks, weighing between 8 kg and 16 kg, were on flat ground, but most of them (12 out of 15) moved during the three- month study.

Richard Norris, one of the four researchers, explained that as the day breaks and frozen rainwater on the floor of the Death Valley melts, rocks sitting on thin sheets of ice started floating just above the ground. As wind pushes those ice sheets, the rocks also move like a tugboat.

Oceanographer Richard Norris, from the La Jolla, Calif.-based Scripps Institution of Oceanography, added, "It seems unlikely, until you're there looking at it. The amazing thing is that in the hottest, driest place on the planet, we have these arctic conditions that are allowing the rocks to move."

During the three-month study, the researchers recorded rocks moving at a sluggish speed of 3 meters to 5 meters per minute and travelling up to 224 meters across the Death Valley.

The research appeared in a recent edition of the journal PLOS One.