Mysterious ‘sailing stones’ existed 200 million years ago, dinosaur fossil reveals
{{#rendered}} {{/rendered}}A sandstone slab containing dinosaur footprints might also contain the track of a sailing stone, scientists announced this week.
The slab, which has been on display since 1896, contains the footprints of a Brontosaurus predecessor that lived during the Early Jurassic period, according to scientists.
However, the sailing stone was not discovered until 2017 by paleontologist Paul Olsen from the Lamont-Doherty Earth Observatory at Columbia University and his colleagues.
{{#rendered}} {{/rendered}}Sailing stones are rocks or boulders that move across landscapes without assistance from gravity, people, or animals. They usually leave tracks as they go.
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This slab of sandstone has been on display since 1896, showing off the scaly footprints of a prosauropod dinosaur. Scientists only recently realized that the deep grooves on the left may be the track of a sailing stone. (Lull, R.S., 1915)
{{#rendered}} {{/rendered}}Olsen and his colleagues believe the trail of the rock could be evidence of a brief freezing event in the tropics some 200 million years ago — the first proof that volcanic winters reached into the humid tropics during the dawn of the dinosaur age.
According to a statement from the university, he and his colleagues believe the sandstone was deposited during the last of a series of eruptions that led to a mass extinction.
“This may be evidence of the cooling caused by the volcanic winter,” says Olsen.