5.3 million years ago, the world’s largest flood refilled the Mediterranean Sea
5.3 million years ago, the world’s largest flood refilled the Mediterranean Sea
By Elizabeth Fernandez | Published: 2025-09-04 17:47:00 | Source: Hard Science – Big Think
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The Mediterranean Sea is connected to the vastness of the Atlantic Ocean by the smallest of natural channels: the Strait of Gibraltar is only about 8 miles wide. the people Glory be to Him Across the strait, it is easy to see from Spain to Morocco on a normal, clear day. It seems that it would not take much for nature to close this connection between Europe and Africa, thus isolating the Mediterranean. Indeed, this has happened before.
About six million years ago, something happened that cut off the Mediterranean Sea. It may have been the Ice Age that lowered sea levels enough to leave a land bridge between Spain and Morocco. It is also possible that the isolation of the Mediterranean is a result of this Tectonic processes.
In the so-called Mycenaean salinity crisis, the Mediterranean Sea then evaporated over a period of about 1,000 years. The area turned into a dry basin located 3 to 5 kilometers below sea level, interspersed with salt lakes that resemble the Dead Sea today. As much as the crisis began slowly, it ended extremely quickly, in a massive flood the likes of which the world had never seen before.
When the Mediterranean dried up
There is interesting evidence showing how extensively the Mediterranean has dried out.
Today huge rivers such as the Nile and Rhone empty into the Mediterranean Sea at sea level. But during the mentioned period, these rivers reached the bottom of the Mediterranean Sea. In the process, they carved large valleys that reach the bottom of the sea, 2,700 meters below sea level. In Cairo, the Nile River The valley has been discovered During excavation work in the Aswan Dam. Cores and subsequent surveys revealed a formation larger than the Grand Canyon. A Similar canyon They were found at the Rhone River, and were carved over a period of less than 100,000 years.
Cores have been revealed beneath the Mediterranean Sea itself Metals Such as gypsum and rock salt, which usually precipitate when salt water dries. In some places salt deposits were found Its thickness reaches 1 km.
The dryness of the Mediterranean may have made its way into legend. The protrusions that rise on either side of the Strait of Gibraltar are known as the Pillars of Hercules. In the year 77 AD, Pliny the Elder described the myth Accordingly, Hercules cut a path across these two rocks, connecting the empty Mediterranean Sea with the Atlantic Ocean once again.
A cyclonic flood fills the Mediterranean Sea
The Messinian salinity crisis came to an abrupt end in what was very likely the largest flood in the planet’s history about 5.3 million years ago. The land bridge between modern-day Spain and Morocco was breached, opening the floodgates to the Zinclic Flood. This massive flood carved a 200-kilometre-long channel through the strait, probably deepening it by about 40 centimeters per day. that Soon a huge amount of water refilled the Mediterranean Sea. Most of the basin was refilled in as little as two years – and perhaps as little as a few months – with the water deepening at a rate of ten meters per day at its peak.
Erosion features preserved underwater allow us to know exactly how strong the flood was. To see, for example, we travel under the Alboran Sea, to the east of the Strait of Gibraltar. Underwater is an ancient volcano behind which a huge amount of sediment is deposited – it is 35 kilometers long, 7 kilometers wide, and 163 meters thick. Although the evidence is not conclusive, Scientists believe this deposit It was likely left behind by a massive flood as it flowed around the volcano. Erosion characteristics indicate that this rush of water was about to occur 1000 times stronger than AmazonThis means that approximately 100 million cubic meters of water flow into the Mediterranean Sea every second.
A huge underwater canyon
But how extensive was this flood? If it had filled the entire Mediterranean, it would have left evidence elsewhere as well. Stretching along the eastern edge of Sicily is an underwater cliff called the Malta Escarpment, which is truly huge – 290 kilometers long and about 4 kilometers high. When the water fell over the Malta Escarpment, it may have passed through the Noto Valley. At 700 metres, Noto is steeper and deeper than any other valley of its kind in the world. Water may have flowed through this narrow inlet into the eastern Mediterranean.
On the eastern side of the escarpment near Noto Canyon are deposits of sediment up to 800 meters thick. The nature of this deposit is distinctive enough Scientists believe Its origin is a great flood. It’s a mixture of rocks, sand and gravel of all shapes and sizes, a mixture similar to what you would expect floodwaters to deposit. If this was indeed a zinc flood, it would mean that the water reached the eastern Mediterranean, near Sicily, making it the largest reservoir for mega-floods in the world.
The Mediterranean is doomed
One day, the Mediterranean Sea may dry up again. If the Strait of Gibraltar is closed, the Mediterranean Sea will likely be closed It dries up in about 1000 years. Over a longer period of time, the African plate moves further and further north and east. recently, The heavier European continent will slide beneath itThe Mediterranean will disappear – this time forever.
This article was first published on Big Think in May 2023. It was updated in September 2025.
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