Jan Bartek – AncientPages.com – A recent study presents significant evidence that a massive ‘megaflood’ was responsible for refilling the Mediterranean Sea, concluding an era when the region was dominated by extensive salt flats.
This event, known as the Zanclean Megaflood, is believed to have ended the Messinian Salinity Crisis between 5.97 and 5.33 million years ago. An international team of scientists, including researchers from the University of Southampton, has identified geological features in South East Sicily that indicate such a large-scale flood occurred in this area.
Artistic interpretation of the Mediterranean geography during its evaporative drawdown, after complete disconnection from the Atlantic. Credit: Paubahi – CC BY-SA 3.0
“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 in a press relase. “Our research provides the most compelling evidence yet of this extraordinary event.”
During the Messinian Salinity Crisis, the Mediterranean Sea was cut off from the Atlantic Ocean and underwent significant evaporation, resulting in extensive salt deposits that transformed the region’s landscape.
Initially, scientists believed this arid period ended gradually over 10,000 years as the sea slowly refilled. However, this theory was challenged by a 2009 discovery of an erosion channel extending from the Gulf of Cadiz to the Alboran Sea. This finding suggested a rapid flooding event known as the Zanclean megaflood, which occurred over two to 16 years.
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
Estimates indicate that this megaflood had a discharge rate between 68 and 100 Sverdrups (Sv), with one Sv representing one million cubic meters per second. Recent research published in Communications Earth & Environment integrates newly identified geological features with geophysical data and numerical modeling to better understand this event.
The study examined over 300 asymmetric ridges across a corridor at the Sicily Sill—a submerged land bridge that once divided the western and eastern Mediterranean basins—providing new insights into this dramatic geological phenomenon.
“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 examining the ridges, the research team discovered a layer of rocky debris on top, composed of material eroded from both the ridge flanks and surrounding areas. This finding suggests that the debris was deposited rapidly and with significant force. This layer is situated at the boundary between the Messinian and Zanclean periods, aligning with when a megaflood is believed to have occurred.
Team members inspecting an exposed section of lithified sediment deformed by the megaflood. Credit Daniel Garcia Castellanos
Utilizing seismic reflection data—a technique akin to geological ultrasound that reveals layers of rock and sediment beneath the surface—the researchers identified a ‘W-shaped channel’ on the continental shelf east of Sicily Sill. This channel, carved into the seabed, links these ridges to Noto Canyon, an underwater valley in the eastern Mediterranean.
The configuration and position of this channel imply it functioned as a massive funnel during ancient times. As megaflood waters surged over Sicily Sill, this channel likely directed them toward Noto Canyon and further into the eastern Mediterranean region.
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To understand this phenomenon better, researchers developed computer models simulating how such floodwaters might have behaved. The simulations indicate that as time progressed, water flow changed direction and intensified—reaching speeds up to 32 meters per second (72 miles per hour). Consequently, deeper channels were carved out while more material was eroded and transported over 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.”
Written by Jan Bartek – AncientPages.com Staff Writer
