The forgotten bridge between Morocco and Spain

5.5 million years ago, the narrowing of the Strait of Gibraltar, particularly the passage between Spain and Morocco, led to a drying of the Mediterranean which lost 70% of its volume of water, indicates a study published Monday in the journal Nature Communications.

The phenomenon occurred between 5.97 and 5.33 million years before Christ, at the end of the Miocene, recall the authors of the study, explaining that the closure of the strait, caused by the movements of the plates tectonics, led to a reduction in water exchanges between the Mediterranean and the Atlantic Ocean, and by extension, a concentration of salts in the sea. Called “Messinian salinity crisis”, in reference to the Italian city of Messina, this phenomenon affected the bottom of the Mediterranean which was “covered with a layer of salts up to 2-3 km thick”, reaching one million cubic kilometers, explains in a press statement, Giovanni Aloisi, CNRS researcher, geochemist at the Institute of Globe Physics, and director of the study.