Rock climbers in Italy have stumbled upon evidence of what appears to be a sea turtle stampede that took place nearly 80 million years ago. Now new research suggests that these ancient marine reptiles were fleeing the earthquake.
The climbers recognized the significance of their find because the grooves in the rock face on Monte Cônero overlooking the Adriatic Sea reminded them of others they had made subtitles earlier that year. These grooves were found in another part of the same regional park and were attributed to a Cretaceous marine reptile that pressed its paddles into the sea floor. They consulted with fellow climber and geologist Paolo Sandroni, who teamed up with him Alessandro Montanaridirector of the Geological Observatory of Coldigioco (OGC).
Sandroni and another team member climbed back into the area to collect rock samples and document the site with a drone.
Hundreds of these footprints are found in the Scaglia Rossa limestone layer in the Cônero Regional Park, a formation that has been extensively studied for decades and preserves millions of years of deep-sea sedimentation, study co-author Montanari told Live Science.
What is now part of the mountain was once a deep sea floor folded and pushed up by tectonic forces millions of years ago, he said. Rock samples collected immediately above the tracks and analyzed by the team reveal important clues about the location of the tracks and the story behind them. For example, they suggest that sea turtles lived about 79 million years ago during the Late Cretaceous period, and they suggest that the limestone was part of an underwater mudslide launched earthquake.
It also supports abundant seismic activity in this formation decade collective studies. Thin sections of rock samples reveal microfossils of organisms that live along the seafloor, suggesting a seafloor environment hundreds of meters deep.
Normally, any tracks left by the animals would be washed away by currents on the sea floor and “worms, clams and [other] benthic organisms,” Montanari said. “They basically garden the sea floor,” he noted. However, the earthquake caused an underwater avalanche within minutes of making the tracks, which he said preserved them.
The only vertebrates large enough to make these tracks in the Late Cretaceous were marine reptiles such as sea turtles, plesiosaurs, and mosasaurs. The latter two are thought to have been largely solitary, but if the ancient sea turtles’ behavior mirrored that of some of today’s species, the researchers said, then it’s possible they foraged near shore or left the water to lay eggs. Whatever brought them together, the earthquake caused them all to flee at once, the team in the study suggested, forcing some turtles to swim in the water above the open sea and others to run away. closer to the deeper seabed. The impending underwater avalanche pushed them further out of the way.
Michael Bentonprofessor of vertebrate palaeontology at the University of Bristol in the United Kingdom, who was not involved in the research, said the study clearly shows the geological context, but questioned which animal made the tracks.
“The tracks are unusual because they appear to show underwater swimming, where the two forelimbs enter the sediment together and the animal pushes forward,” he told Live Science. Most vertebrates tend to “walk or swim with their limbs out of sequence” rather than putting down two limbs at the same time, he said. “Sea turtles generally have a very efficient swimming mode,” he said, “a bit like underwater flying, where the front blades swing” much like a figure-eight pattern that doesn’t seem to match the tracks found. He also questions why they wouldn’t simply “leave the seabed and swim” away.
Montanari said that while the footprints would benefit from further research, geologically it is clear that an earthquake-triggered underwater avalanche occurred. He said he hopes their work will prompt fossil experts to further study the site.
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