A groundbreaking study published in Communications Earth & Environment has revealed definitive evidence of how the Zanclean mega-flood replenished the Mediterranean Sea, marking the end of a dry period spanning from 5.97 to 5.33 million years ago. The research, conducted by an international scientific team including researchers from the University of Southampton, has identified distinctive geological features in southeastern Sicily that point to an enormous flood event in the region.
The research team analyzed more than 300 asymmetrical ridges within a geological corridor that crosses a submarine ridge – once the barrier between the Mediterranean's western and eastern basins. The scientists discovered a distinctive "W-shaped channel" in the continental shelf east of the ridge. This channel's unique shape and position indicate it functioned as a massive funnel, directing water toward the submarine Noto Canyon during the mega-flood event.
When the team sampled these ridges, they found a covering layer of rock fragments dating to the crucial transition period between the Mediterranean's dry phase and its refilling. This layer contained eroded materials from nearby areas, suggesting rapid deposition under tremendous force.
"The Zanclean megaflood was an awe-inspiring natural phenomenon, with discharge rates and flow velocities dwarfing any other known floods in Earth's history," Dr. Aaron Micallef, the study's lead author and researcher at the Monterey Bay Aquarium Research Institute in California, said.
"The morphology of these ridges is compatible with erosion by large-scale, turbulent water flow with a predominantly north easterly direction," Paul Carling, professor emeritus at the University of Southampton and study co-author, said. "They reveal the immense power of the Zanclean Megaflood and how it reshaped the landscape, leaving lasting imprints on the geological record," he added.
This discovery challenges the previous scientific consensus, which held that the Mediterranean's dry period ended gradually over 10,000 years.
To better understand the flood's dynamics, the research team developed sophisticated computer models simulating water behavior during the event. Their models indicate that the flood's direction shifted and its intensity increased over time, ultimately reaching velocities of up to 32 meters (105 feet) per second.
The scale of the Zanclean mega-flood was staggering – calculations suggest it discharged water equivalent to 40,000 Olympic swimming pools into the Mediterranean Sea every second, or 68 billion liters (18 billion gallons) per second.
The study provides crucial context about the period between 5.97 and 5.33 million years ago, when the Mediterranean Sea was cut off from the Atlantic Ocean and largely evaporated, resulting in massive salt deposits that transformed the regional landscape.
