A massive flood five million years ago saw water rushing from the Atlantic Ocean and piercing its way through the  Strait of Gibraltar and into the Mediterranean Sea, which was empty at the time. The water moved like a speeding car and gouged out an area about the size of a skyscraper.

Advertisment

The Mediterranean was filled with water from the Atlantic in a couple of years, The Conversation reported. The timeline could also have been only a few months, the researchers say. The flood at its peak added about 1,000 times the water of the modern-day Amazon River.

An underwater canyon that lies along the Strait of Gibraltar was studied in the past, and a 2009 study states that this flood is what carved it. This event is known as the Zanclean megaflood and is believed to be the largest single flood recorded on Earth. However, not all researchers agree on this.

Also Read: Pieces of lost continent found under Antarctica and India point to one thing

Advertisment

A new study investigated sedimentary rock from the Zanclean era and sought to understand how water surged through "a gap between modern-day Sicily and mainland Africa to refill the eastern half of the Mediterranean."

Mediterranean was dry 6 million years ago

In the late 19th century, scientists figured out that something unusual had happened about 5 to 6 million years ago. All the seas dried up, and this period is known as the “Messinian” age. Digging into the rocks below the Mediterranean seafloor revealed a kilometres thick layer of salt. This proved a vast environmental change occurred 6 million years ago, and tectonic activity isolated the sea from the Atlantic Ocean.

Advertisment

Also Read: What lies below the Antarctica ice sheet? Rocky mountains, canyons and...

They also discovered fossils from shallow, low-salt lakes, showing that the water had evaporated, leading to the sea falling down by a kilometre from its current level. Only about 11 per cent of Mediterranean marine species survived this incident.

Sudden and cataclysmic flood created a trench

In 2009, scientists learned that an underwater trench between the Atlantic Ocean and the Mediterranean Sea was likely created by a "sudden and cataclysmic flood."

Giovanni Barreca, a co-author of the latest study, says the team studied the low hills near the Sicily Sill, which appeared unusual. They were more aligned and streamlined, similar to the hills in Washington state in the US. The latter were formed by a megaflood at the end of the last Ice Age, and the similarity led them to research further.

They assumed that rock debris eroded from the base of the depressions should be near the top of the hills. The assumption proved right, and they discovered rock debris of up to the size of a boulder.

The team created a model that showed that water, 40 metres or more deep, gushing at the speed of  115 kilometres per hour, carved the hills.