Marine scientists have uncovered evidence of one of the largest floods in Earth’s history in the central Mediterranean seafloor.
The flood, known as the Zanclean flood, is thought to have ended the Messinian Salinity Crisis (MSC), one of the most dramatic events on Earth during the Cenozoic era between 5.96 and 5.33 million years (Myr) ago.
During this period, the Mediterranean Sea became partially dried up.
The sea was sealed off from the Atlantic by the precursor of the Strait of Gibraltar and it happened about 5.96 million years ago.
Due to shrinkage of its connection with the Atlantic Ocean, the Mediterranean Sea was transformed into a gigantic saline lake that was partially evaporated by the dry climate of the region at the time.
Now, an international team of geoscientists has discovered an extensive buried mass of material that is thought to have been eroded and transported by the Zanclean flood. This mass covers an area equivalent to that of the island of Crete and is up to 900 m thick in places. The passage of the Zanclean flood across the Malta Escarpment – a long submarine limestone cliff – resulted in a 1.5 km high waterfall (equivalent to five times the height of the Eiffel Tower).
According to one of the theories proposed to explain the refilling of the Mediterranean Sea at the end of the MSC some 640,000 years later is a catastrophic flood through the Strait of Gibraltar.
This water eroded a 5 km wide and 20 km long canyon on the seafloor that is still preserved underwater offshore the city of Noto (south-east Sicily).
This important discovery demonstrates that the level of the Mediterranean Sea during the MSC dropped by more than a thousand meters, and that the end of the MSC coincided with a catastrophic flood that affected the entire Mediterranean Sea.
This study, which was published in the international journal “Scientific Reports”.