Messinian Salinity Crisis

The Messinian salinity crisis took place from about 5.96 to 5.33 million years ago, near the end of the Miocene epoch, when the closing of the Strait of Gibraltar isolated the Mediterranean Sea from the Atlantic Ocean. The basin underwent partial to nearly complete desiccation, drying into a deep depression reaching 3 to 5 kilometers below normal sea level, while rivers carved deep canyons into the exposed margins and thick salt deposits accumulated from evaporation. The crisis ended when the strait reopened around 5.33 million years ago, triggering the Zanclean flood that rapidly refilled the basin. It caused major extinctions among marine life native to the Mediterranean, while the temporary land connection let animals move between the Iberian Peninsula and North Africa and reach remote islands such as the Balearics, where some species remained isolated for millions of years afterward.