Zanclean flood
The Zanclean flood, or Zanclean deluge, is theorized to have refilled the Mediterranean Sea 5.33 million years ago. This flooding ended the Messinian salinity crisis and reconnected the Mediterranean Sea to the Atlantic Ocean, although it is possible that even before the flood there were partial connections to the Atlantic Ocean. The re-connection marks the beginning of the Zanclean age, the earliest age on the geologic time scale of the Pliocene.
According to this model, water from the Atlantic Ocean refilled the dried-up basin through the modern-day Strait of Gibraltar. Ninety percent of the Mediterranean Basin flooding occurred abruptly during a period estimated to have been between several months and two years, following low water discharges that could have lasted for several thousand years. Sea level rise in the basin may at times have reached rates greater than 10 metres per day (5 fathom/d; 30 ft/d). Based on the erosion features preserved until modern times under the Pliocene sediment, Garcia-Castellanos et al. estimate that water rushed down a drop of more than 1,000 metres (3,300 ft) with a maximum discharge of about 100 million cubic metres per second (3.5 billion cubic feet per second), three orders of magnitude larger than the present-day Amazon River. Studies of the underground structures at the Strait of Gibraltar show that the flooding channel descended gradually toward the bottom of the basin rather than forming a steep waterfall.