Massive past waterfall discovered beneath the seafloor

14 March 2024, by CEN News

Photo: Marc Petrikowski

On an expedition through mid-March on board the German research vessel METEOR, an international team led by Christian Hübscher, a professor at Universität Hamburg’s CEN, discovered a 1,500-meter-tall past waterfall beneath the seafloor south of Sicily. It was formed more than five million years ago, when the nearly empty Mediterranean began refilling.

During the Messinian salinity crisis, an event that took place more than five million years ago, the sea level in the Mediterranean dropped by between 1,300 and 2,400 meters. Broad expanses of today’s Mediterranean became salt deserts. The Mediterranean can roughly be divided into two (western and eastern) deep-sea basins. Underwater, the two are separated by a submarine ridge, which is less than 100 meters below the surface at its ends and stretches from Sicily to North Africa. The western basin was filled when the Strait of Gibraltar opened. But what filled the eastern basin?

On board the METEOR, an international team looked for evidence of how the basin was filled. With the aid of imaging technologies, they created cross-sections of the seafloor at the ridge – extending down to 1,000 beneath the floor. There, buried beneath more recent deposits, they discovered a canyon measuring more than ten kilometers across, which was formed when a 1,500-meter-high waterfall located on the ridge’s eastern slope began filling the eastern Mediterranean. According to expedition leader Christian Hübscher, “Further analyses will tell us how quickly the Mediterranean filled. It may have only taken a few years.”