The jumbled deposits of rocks found on a hilltop in southeastern Sicily are left behind by the Great Flood, the largest known flood in Earth's history, which refilled the Mediterranean Sea five million years ago.

Rock deposits and eroded hills in this part of the Italian island of Sicily are the first evidence found on land of a mega-flood, scientists say. pole curling at the University of Southampton, UK. “You can actually walk around and look at it,” Carling said.

About 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean Sea separated from the Atlantic Ocean and began to dry up. Vast salt deposits were formed during this period, and sea levels may have fallen by more than a kilometer.

About 5.3 million years ago, water once again began to flow through the Strait of Gibraltar into the Mediterranean Sea. Researchers initially thought the giant waterfall near Gibraltar had been reclaimed over tens of thousands of years.

But in 2009, a massively eroded channel was discovered at the bottom of the strait, suggesting more sudden deluges could occur. Since then, this evidence has continued to grow.

Carling said the flood first filled the western basin of the Mediterranean Sea. The eroded topography of the ocean floor suggests that it then spilled into the eastern basin over an underwater ridge known as the Sicilian Sill.

team members Giovanni Barreca The professor at the University of Catania in Italy, who grew up in southeastern Sicily, suspected that the land there was also formed by the Great Flood. So he and his fellow researchers took a closer look at the rock samples and analyzed them.

Sure enough, we found that the intricate deposits near the tops of some hills contained rocks that had been eroded from deeper layers and somehow transported to the top of the hills. “You can tell by their nature that they come from a lower level,” Carling says. “And they were carried over this hill.”

Many of the hills themselves have a streamlined shape, resembling the hills of Montana carved out by the great floods caused by the bursting of ice dams at the end of the last ice age. “They're very distinctive,” Carling says. “And only a very large, massive flood could streamline a feature of this magnitude.”

The researchers estimated that at the peak of the flood, water was flowing at about 115 kilometers per hour, covering the top of the hill, which is about 100 meters above modern sea level, with about 40 meters of water.

Researchers also investigated the ocean floor around Sicily and found further evidence of the deluge, including eroded ridges and channels. Their modeling suggested that the entire Mediterranean Sea was backfilled between two and 16 years, but the main flooding event in Sicily probably lasted only a few days, Carling said.