The culmination of the Messinian Salinity Crisis, caused by the closure of the Mediterranean and an overwhelming greenhouse effect causing it to slowly evaporate; the high salinity of the Black Sea, Caspian Sea, and Aral Sea are the result of this phenomenon. During this period, perhaps coinciding with the 25,000-year precession of the equinoxes, phases of evaporation and drying of the Mediterranean followed by phases of subsequent refilling. During the Messinian Salinity Crisis, salt deposits 1.5 km thick existed on the Mediterranean seabed (a million cubic kilometers of salt were locked there—changing the salinity of the rest of the world’s seas). Temperatures of 80°C (176°F) atop these deposits prevented the Nile and other major rivers from contributing enough water to sustain the Mediterranean Sea by a factor of ten. Then, 5.3 million years ago, Gibraltar reopened, the Atlantic Ocean flooded the Mediterranean (Langelian Flood) within a single century (the level rose up to 10m per day).
