EARTH × CLIMATE

The Mediterranean Dries Out

~5.96 to 5.33 million years ago

Phanerozoic · Cenozoic · Neogene · Miocene

The Mediterranean lost its link to the Atlantic and mostly evaporated, leaving salt flats a kilometre below sea level and up to two kilometres of salt on the floor. Then the Atlantic broke back through at Gibraltar. A channel two hundred kilometres long and more than two hundred and fifty metres deep, cut across the strait, gives the scale of what came through: a discharge perhaps a thousand times the Amazon.

Why it matters

An entire sea vanished and returned inside a million years, and the channel the flood cut is still down there under the strait. Whether the refill took months or centuries is argued from that channel and from models, but either figure is fast enough to be difficult to picture.

Dating & uncertainty

The salt on the sea floor, up to two kilometres of it, is not in doubt. How deep the water fell, and whether the refill was a flood of months or a rise of centuries, is argued from eroded channels and modelling.

Sources

1. García-Castellanos et al. (2009), Nature · Catastrophic flood of the Mediterranean after the Messinian salinity crisis
2. Micallef et al. (2018), Scientific Reports · Evidence of the Zanclean megaflood in the eastern Mediterranean Basin
3. Micallef et al. (2024), Communications Earth & Environment · Land-to-sea indicators of the Zanclean megaflood

Earth history as one day

23:58:061 min 53 s before midnight

if Earth’s 4.54 billion years were compressed into a single day