So how did this salty basin become the Mediterranean Sea once again? Well the situation reversed in exactly the same way that it was caused. The African and Eurasian tectonic plates continued to move.

Scientists reveal new details about the 5.3-million-year-old flood, which triggered earthquakes, generated tropical-storm ...

As tectonic plates moved around, they sealed off the Strait of Gibraltar, essentially isolating the Mediterranean Sea. Gradually, the sea became a desert basin with kilometer-thick salt deposits.