The Origin of Self-Moving Stones in Death Valley

Self-moving rocks may have appeared hundreds of millions of years ago, sliding across the ground as the ice melted in the early Jurassic.

The Origin of Self-Moving Stones in Death Valley
The rock moves on its own in Death Valley. (Image: Wikipedia).

Paleontologist Paul Olsen of Columbia University and his colleagues found the earliest evidence of rocks moving on their own millions of years ago. They published the study during the annual meeting of the American Geophysical Union.

The self-moving rocks baffled geologists for a long time because they seemed to slide across the desert, leaving long trenches without human or animal intervention. The dry Racetrack Playa lake bed in Death Valley in California is famous for its numerous rocks of this type. Researchers think that ice, wind and even bacteria may be to blame for the heavy rocks to move.

The Origin of Self-Moving Stones in Death Valley
Grooves left by self-moving rocks between dinosaur footprints. (Photo: Sun).

Olsen’s team found a groove left by a self-moving rock in an intact dinosaur footprint fossil, dating back 200 million years. They observed long trails between the footprints of prehistoric animals. This evidence is consistent with the hypothesis of a brief glaciation of the early Jurassic, ice-shifted rocks that formed after the entire area was submerged. They slide along the ice as the ice melts, creating a muddy trench that dries and hardens over time.

The researchers concluded that ice was the most likely cause because dinosaur footprints provided no evidence of a bacterial connection.