European researchers, led by Daniel Garcia-Castellanos from the CSIC (Research Council of Spain), have solved one of the oldest mysteries of the world by finding details of the catastrophic flood that refilled the Mediterranean Sea over 5 million years ago.

The team found that the catastrophic Zanclean flood occurred when Atlantic waters found their way into the cut-off and desiccated Mediterranean basin. They said that a 200km channel across the Gibraltar strait was carved out by the floodwaters and the resulting flood could have filled the basin within two years. Dr. Daniel Garcia-Castellanos said that they laid the foundations for this study by working on tectonic lakes. They developed a model of how the mountain lakes quickly “cease to exist” when erosion produces “outlet rivers” that drain them.

He told BBC, ”This same principle could be used to explain the Zanclean flood that reconnected the Mediterranean with the rest of the World’s oceans. We could for the first time link the amount of water crossing the channel with the amount of erosion causing it to grow over time. Using existing borehole and seismic data, his team showed how the flood would have begun with water spilling over a sill. The water would have gradually eroded a channel into the strait, eventually triggering a catastrophic flood. This extremely abrupt flood may have involved peak rates of sea level rise in the Mediterranean of more than 10m per day. Previous estimates of the duration of the flood were very variable because scientists “had to assume the size of the channel” rather than measure it.”

News and picture source: BBC News (Victoria Gill, science reporter)