Megafloods eroded the mountain range of southeastern Sicily
Kevin Sciberras and Neil Petroni
The jumbled rock found on top of the hills of southeastern Sicily left the megaflood that refilled the Mediterranean Sea 5 million years ago – the largest known. the floods An event in the history of the earth.
Rock deposits and eroded hills in a region of Sicily, Italy, are the first terrestrial evidence of the megaflood, he says. Paul Carling at the University of Southampton in the UK. “You can actually walk around and see,” Carling says.
About 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean Sea was cut off from the Atlantic Ocean and began to dry up. Large salt deposits formed at this time and sea levels may have dropped a kilometer or more.
The water About 5.3 million years ago it began to flow again through the Strait of Gibraltar into the Mediterranean. Researchers initially thought that a giant waterfall near Gibraltar had refilled over a period of tens of thousands of years.
But in 2009, the discovery of a massive eroded channel He pointed to a much more violent megaflood at the bottom of the strait. The evidence for this has been mounting ever since.
This megaflood first filled the western basin of the Mediterranean Sea, says Carling. Eroded features on the seafloor suggest that it then spilled over the underwater ridge, known as the Sicilian margin, into the eastern basin.
Team member Giovanni Barreca At the University of Catania in Italy, who grew up in southeastern Sicily, he suspected that megafloods had also shaped the land there. So he and his researchers took a closer look and analyzed the rock samples.
To be sure, the disturbed deposits near the top of some hills contain rocks that have been eroded from much deeper layers and somehow carried to the top of the hill. “You can tell by their nature that they were of that low level,” says Carling. “And they led them up these mountains.”
Many of the hills themselves have a slight shape, and resemble The ones in Montana which were carved by a great flood that broke an ice dam at the end of the last glacial period. “They’re pretty distinctive,” says Carling. “And the only thing that can facilitate features of this scale is deep, large-scale flooding.”
More Sicilian mountain ranges shaped by megafloods
Daniel García Castellanos
The team estimated that at the height of the flood, the water was moving at around 115 kilometers per hour and covered the tops of the hills – which are about 100 meters above the current sea level – by around 40 metres.
The researchers also looked at the sea floor around Sicily and found more evidence of the megaflood, such as eroded ridges and channels. Their modeling suggested that the entire Mediterranean Sea would fill between two and 16 years, but the main floods in Sicily probably lasted only a few days, Carling says.
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