Pre-Zanclean Flood Mediterranean. Artwork showing the Mediterranean Sea during the Messinian Salinity Crisis (MSC) when large parts evaporated due to the connection with the Atlantic Ocean (the Strait of Gibraltar) being sealed. The Mediterranean was reduced in area to the extent shown here, which is just prior to the refilling, an event known as the Zanclean Flood. This flood occurred around 5.33 million years ago. One hypothesis for what triggered the Messinian Salinity Crisis is a period of glaciation, shown here as a large ice cap covering Northern Europe. However, it is thought that tectonic mechanisms played a greater role in causing the salinity crisis.