New Proof Bolsters Idea of Megaflood That Refilled the Mediterranean Hundreds of thousands of Years In the past

Hundreds of thousands of years in the past, the Mediterranean Sea evaporated. It might have then been refilled by the biggest flooding occasion ever skilled on Earth.

A global group of researchers has uncovered new proof supporting the Zanclean megaflood, a theorized occasion that refilled the Mediterranean Sea after the Messinian Salinity Disaster had reworked it right into a dry, salty panorama. As detailed in a December 28 study revealed within the journal Communications Earth & Setting, the researchers mixed newly recognized geological options in Sicily with geophysical information and pc fashions to probably present essentially the most intensive look into the traditional megaflood identified thus far.

“The Zanclean megaflood was an awe-inspiring pure phenomenon, with discharge charges and stream velocities dwarfing every other identified floods in Earth’s historical past,” Aaron Micallef of the Monterey Bay Aquarium Analysis Institute in California, who led the examine, stated in a College of Southampton statement. “Our analysis offers essentially the most compelling proof but of this extraordinary occasion.”

Between 5.97 and 5.33 million years in the past, the Messinian Salinity Disaster brought on the Mediterranean Sea to be lower off from the Atlantic Ocean and evaporate into an expanse of salt deposits. Scientists beforehand theorized that, over a interval of 10,000 years, the Mediterranean basin regularly refilled with water. Nonetheless, the 2009 discovery of an erosion channel that stretches from the Gulf of Cadiz on Spain’s Atlantic coast to the Alboran Sea east of the Strait of Gibraltar challenged this principle, and as a substitute led scientists to recommend a single flooding occasion.

“This megaflood is assumed to have been attributable to overtopping Atlantic waters via a Late Messinian isthmus close to the trendy Gibraltar Strait, which initially crammed the western Mediterranean, and subsequently spilled over the intrabasinal Sicily Sill, filling the japanese Mediterranean,” the researchers wrote within the new examine. Scientists estimate that the megaflood lasted between two and 16 years, and discharged between 2.4 and three.5 billion cubic toes (68 and 100 million cubic meters) per second, in line with the examine.

The group recognized greater than 300 uneven, steady ridges close to the Sicily Sill, a now-underwater land bridge that when divided the western Mediterranean from the japanese Mediterranean. The ridges have been layered in particles eroded from the ridge flanks and the encircling space, which level to a fast and intense deposition course of. The layers date to between the Messinian (7.2 million to five.3 million years in the past) and Zanclean (5.3 to three.60 million yr in the past) durations, aligning completely with the proposed timing of the Zanclean megaflood, round 5.3 million years in the past.

“The morphology of those ridges is suitable with erosion by large-scale, turbulent water stream with a predominantly north easterly course,” Paul Carling of the College of Southampton, who participated within the examine, stated within the assertion. “They reveal the immense energy of the Zanclean Megaflood and the way it reshaped the panorama, leaving lasting imprints on the geological report.”

Carling and his colleagues additionally found a “W-shaped channel” within the seabed east of the Sicily Sill, connecting the ridges to an underwater valley within the japanese Mediterranean referred to as the Noto Canyon. The researchers suggest that when the Zanclean megaflood had crammed the western Mediterranean and at last spilled over the Sicily Sill, the channel funneled water into the japanese elements of the ocean.

The group additionally developed pc fashions to reconstruct this dynamic. The simulations recommend that the water modified instructions and grew extra intense over time, reaching a discharge of as much as 72 miles per hour (116 kilometers per hour).

“These findings not solely make clear a important second in Earth’s geological historical past but in addition show the persistence of landforms over 5 million years,” Micallef added. “It opens the door to additional analysis alongside the Mediterranean margins.”

Although the Zanclean megaflood stays only a principle, one factor is for certain—5.3 million years in the past, the Mediterranean Sea most likely wasn’t the idyllic journey vacation spot it’s at present.