Material World: The Six Raw Materials That Shape Modern Civilization

by Ed Conway

Between 5 and 6 million years ago—long after that meteor crashed into the Great Sand Sea but long before the arrival of Homo sapiens—the Med was cut off from the Atlantic and over hundreds of thousands of years it dried out almost completely, coming to resemble a giant version of today’s Dead Sea. The Strait of Gibraltar eventually reopened and, in what must have been the most extraordinary sight, the Atlantic suddenly gushed back through in a monumental tidal wave. While it is hard to imagine witnessing such a thing today, you can at least feel, or rather taste, the legacy, for the waters of the Mediterranean are still unusually salty, with about 38 parts per thousand of salt compared with 35ppt on average in other oceans. As Eurasia continues to collide with Africa, geologists expect that in the coming millions of years the strait will close again, this time permanently. The Mediterranean will eventually dry up and disappear altogether, leaving a layer of buried salts in its wake, much like the Zechstein Sea.[1]