Scientists have discovered a giant underwater canyon in the eastern Mediterranean Sea that likely formed just before the sea transformed to a mile-high salt field.
The canyon formed around 6 million years ago, at the onset of the Messinian salinity crisis (MSC), when the Gibraltar gateway between the Atlantic Ocean and Mediterranean Sea narrowed and eventually pinched shut due to shifts in tectonic plates. The Mediterranean Sea became isolated from the world's oceans and dried up for roughly 700,000 years, leaving behind a vast expanse of salt up to 2 miles (3 kilometers) thick in some places.
