A cataclysmic flood may have filled the Mediterranean in less than two years:
A new model suggests that at the flood’s peak water poured from the Atlantic into the Mediterranean basin at a rate one thousand times the flow of the Amazon River, according to calculations published in the Dec. 10 Nature.“In an instantaneous flash, the dry Mediterranean became a normal Mediterranean like we see it today,” says lead author Daniel Garcia-Castellanos of Spain’s Consejo Superior de Investigaciones Cientificas (CSIC) in Barcelona.
He and his colleagues calculate that at the height of the flood, water levels rose more than 10 meters and more than 40 centimeters of rock eroded away per day. The model also shows that 100 million cubic meters of water flowed through the channel per second, with water gushing at speeds of 100 kilometers an hour. Rather than a Niagara Falls-esque cascade from the Atlantic into the Mediterranean, the team’s results imply a torrent several kilometers wide at a fairly gradual slope.
Any geological record of erosion from rushing waters seemed lost:
But Garcia-Castellanos and colleagues found it, thanks to plans for an underground train. Cores drilled in the seafloor as part of preparations for the Africa-Europe tunnel project, which hopes to run trains under the Strait of Gibraltar from Spain to Morocco, revealed a deep channel filled with loose sediment. Using the drilling data and previously collected seismic data, the researchers determined that the channel is 200 kilometers long, between 6 and 11 kilometers wide, and between 300 and 650 meters deep.Other geologists who had noticed the channel thought it had formed through erosion by rainwater in a river network, like in the Rhone or Nile rivers. But while those river channels are V-shaped, the new data show that the Strait of Gibraltar channel has the distinctive U-shape of the seafloor beneath the Strait of Dover. This shape is a hint that the strait formed in a torrential flood.
Using equations derived from observations of mountain rivers, the team of researchers modeled how the flood might have progressed: The flood started gradually, but as the sill between the Atlantic and the dry Mediterranean wore down, the rate of water flowing and rock eroding increased exponentially. As more water flowed over the sill, more rock wore away, allowing ever more water to spill in.
The calculations show an upper limit of two years for how long it took to fill the Mediterranean. But Garcia-Castellanos says it could have been as short as a few months.
Hence the Hyborian Age.