Monday, December 12, 2011

The Dead Sea evaporated during warmer climate 120,000 years ago

Holy Land’s salt lake ran out of water during ancient warm spell
Science News Web edition : Wednesday, December 7th, 2011

UNDEAD SEAThe Dead Sea, which has been shrinking for decades, may be fated to disappear completely, as it did about 120,000 years ago.Dead Sea Deep Drilling Project
SAN FRANCISCO — The Dead Sea died once. During a warm period long ago it dried up completely, new evidence reveals.

That’s bad news for the lake today. It’s been shrinking for decades and may be about to die again.

“The lake may actually go dry soon,” Emi Ito of the University of Minnesota in Minneapolis said December 5 at a meeting of the American Geophysical Union.

Ito and colleagues examined lake bed cores dug up by the Dead Sea Deep Drilling Project. Sediments in these cores, deposited over 200,000 years, record the history of the lake.

In theory, the supersalty Dead Sea should be protected against completely drying up; salt increases the amount of heat required to evaporate water. Computer simulations have suggested that a shrinking Dead Sea should eventually stabilize as it gets saltier and saltier.

But smooth pebbles buried 253 meters beneath the present-day lake bed suggest that the Dead Sea was once water-free. What’s more, these stones sit atop about 45 meters of salt.
“That's how much salt we would expect if we were to take the entire Dead Sea today and evaporate it,” said Steven Goldstein of Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y.

The researchers haven’t used radiocarbon dating to figure out the age of the sediments, but the team estimates that the lake vanished 120,000 years ago. A warmer climate at that time that could have dried up the Dead Sea’s water sources.

Today the Dead Sea is threatened again, this time by the diversion of water from the Jordan River for irrigation and other uses. Now fed only by mountain runoff and underwater springs, the Dead Sea dropped 10 meters between 1997 and 2008.

If the Dead Sea disappears again, though, its history does offer some hope. The lake has already come back to life once. Perhaps this biblical body of water could be resurrected again. 

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