Scientists Uncover Evidence of a Colossal Megaflood That Refilled the Mediterranean Sea

Discoveries in Southeast Sicily reveal the massive scale of the Zanclean Megaflood, which refilled the Mediterranean Sea and ended the dry, salt flat-dominated landscape of the Messinian Salinity Crisis in a remarkably short period. (Artist’s concept.) Credit: SciTechDaily.com

In a groundbreaking study, researchers unveiled compelling evidence of the Zanclean Megaflood, a colossal event that refilled the Mediterranean Sea in mere years, reshaping its landscape with unprecedented water flow and velocities.

This event, which ended the Messinian Salinity Crisis, altered the geological and environmental makeup of the region, leaving lasting imprints that challenge previous theories about gradual changes.

A recent study presents strong evidence that a massive ‘megaflood’ refilled the Mediterranean Sea, bringing an end to a period when the region was largely covered by salt flats.

Researchers believe this event, known as the Zanclean Megaflood, marked the conclusion of the Messinian Salinity Crisis, which lasted between 5.97 and 5.33 million years ago.

An international team of scientists, including researchers from the University of Southampton, has identified geological formations in southeastern Sicily that suggest a sudden, large-scale flooding event swept across the area.

Ridge Eroded by Zanclean Megaflood. Aerial photo of a ridge eroded by the megaflood located north-east of Masseria del Volpe, south-east Sicily Aerial photo of a ridge eroded by the megaflood located north-east of Masseria del Volpe, south-east Sicily. Credit: Kevin Sciberras and Neil Petroni

“The Zanclean megaflood was an awe-inspiring natural phenomenon, with discharge rates and flow velocities dwarfing any other known floods in Earth’s history,” said Dr. Aaron Micallef, lead author of the study and researcher at the Monterey Bay Aquarium Research Institute in California. “Our research provides the most compelling evidence yet of this extraordinary event.”

During the Messinian Salinity Crisis, the Mediterranean Sea became isolated from the Atlantic Ocean and evaporated, leading to vast salt deposits that reshaped the region’s landscape.

For years, scientists had thought that this dry period ended gradually, with the Mediterranean refilling over a period of 10,000 years. However, this idea was challenged by the discovery of an erosion channel stretching from the Gulf of Cadiz to the Alboran Sea in 2009. The finding pointed to a single, massive flooding event, lasting between two and 16 years, which became known as the Zanclean megaflood.

Estimates suggest the megaflood had a discharge from 68 to 100 Sverdrups (Sv), with one Sv equal to one million cubic meters per second.

The new research published in the journal Communications Earth & Environment combines newly discovered geological features with geophysical data and numerical modeling to provide the most comprehensive picture yet of the megaflood.

The researchers investigated over 300 asymmetric, streamlined ridges in a corridor across the Sicily Sill – a submerged land bridge that once separated the western and eastern Mediterranean basins.

Lithified Sediment Deformed by Zanclean Megaflood. Team members inspecting an exposed section of lithified sediment deformed by the megaflood. Credit: Danel Garcia Castellanos

“The morphology of these ridges is compatible with erosion by large-scale, turbulent water flow with a predominantly north-easterly direction,” says Professor Paul Carling, an Emeritus professor in the School of Geography and Environmental Science at the University of Southampton and a coauthor of the study.

“They reveal the immense power of the Zanclean Megaflood and how it reshaped the landscape, leaving lasting imprints on the geological record.”

By sampling the ridges, the team found they were topped with a layer of rocky debris containing material eroded from the ridge flanks and the surrounding region, indicating it was deposited there quickly and with immense force.

This layer is right at the boundary between the Messinian and Zanclean periods when the megaflood is believed to have occurred.

Using seismic reflection data – a kind of geological ultrasound allowing scientists to see layers of rock and sediment beneath the surface, the researchers discovered a ‘W-shaped channel’ on the continental shelf east of the Sicily Sill.

This channel, carved into the seabed, connects the ridges to the Noto Canyon – a deep underwater valley located in the eastern Mediterranean.

The shape and location of the channel suggest that it acted like a massive funnel. When the megaflood waters poured over the Sicily Sill, this channel likely carried the water toward the Noto Canyon and into the eastern Mediterranean.

The researchers used computer models to simulate how the megaflood might have behaved. Their findings suggest that the floodwaters shifted direction and gained strength over time, reaching speeds of up to 32 meters per second (72 miles per hour). As the flood intensified, it carved deeper channels, eroded large amounts of material, and carried sediment across greater distances.

“These findings not only shed light on a critical moment in Earth’s geological history but also demonstrate the persistence of landforms over five million years,” Dr. Micallef added. “It opens the door to further research along the Mediterranean margins.”

by Aaron Micallef, Giovanni Barreca, Christian Hübscher, Angelo Camerlenghi, Paul Carling, Jose Maria Abril Hernandez, Raúl Periáñez, Daniel Garcia-Castellanos, Jonathan Ford, Benedikt Haimerl, Matthias Hartge, Jonas Preine and Antonio Caruso, 28 December 2024, Communications Earth & Environment.

The research was supported by the National Geographic Society, Deutsche Forschungsgemeinschaft, and the David and Lucile Packard Foundation.

A pretty good fantasy series by Randall Garrett and Vicki Ann Heydron - The Gandalara Cycle - is set in the dry bed of the Mediterranean. The last book of the series has the dam at Gibraltar beginning to give way as the inhabitants frantically climb the walls to higher ground. This is one of my periodic re-reads. They were supposedly written mostly by Heydron - Garrett’s wife - from an outline that he made.

The point is that the Grand Canyon could not be cut into ROCK in such a short period as the bozo theories posted on YT and elsewhere suggest, and the oft cited example of “Stop Canyon” at Mt. St. Helens is irrelevant and even silly.

I believe the land mass that gave way at Gibraltar caused a massive “vacuum” surge from the ocean floor as far west as the Caribbean sea.

Please do not get me started on the sediment found in the mountains of Peru that are only found elsewhere on the Pacific ocean floor.

Well, now. Indeed, you are correct. I misread the badly worded passage, made clear when I read the source paper.

But the problem with the study - not least of which is the timeline - is that it’s nonsensical, basing its conclusions exclusively upon a study area which belies such water flow in their study area between Isla Palermo and the Sicilian coast based upon Mediterranean bathymetry.

Worse, from the paper itself:

“Validation of the Zanclean megaflood hypothesis requires directly characterising the evidence left by the passage of flooding waters in terms of geomorphology, sedimentology, and stratigraphy.”

Study area comprising a mere tens of square kilometers of shelf off Sicily, and

“...the megaflood hypothesis remains subject to debate25,26,27.”

Ironically, the ‘Ancient Apocalypse’ hypothesis has abundantly more evidence and remains firmly in the realm of tin-hat study. I wonder how much the authors were paid for their worthless observations...

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