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Book Review 244: The Mediterranean Was a Desert
August 26, 2012 - Harry Eagar
THE MEDITERRANEAN WAS A DESERT: A Voyage of the Glomar Challenger, by Kenneth J. Hsu. 197 pages. Princeton paperback
This little book leaves a reader with a lot to think about.
For one thing, geologist Kenneth Hsu never mentions where the Glomar Challenger came from – it was one of the devil's offspring of the Cold War, one of only a very few CIA harumscarum projects to provide any actual benefits to the citizenry, although only after the CIA had given up the ship.
I doubt today any scientific author would fail to mention the origins of the ship, but Hsu wrote in 1983, and attitudes have loosened up since then.
The voyage took place back in 1970, and now I suppose everyone with even a passing interest in geology thinks of a dried up Mediterranean Sea as “something we have always known about,” the way we have “always known” that continents drifted.
But the discovery that the Mediterranean had dried out – the proof lies in certain types of evaporite rocks that can only form in the dry – came not so long after the clinching evidence for plate tectonics was published. Both findings were met with skepticism, even incredulity at first, but while some theories are hard to swallow, the evidence for a dried out Mediterranean was straightforward enough, once it was obtained.
The drama of “The Mediterranean Was a Desert” comes from how difficult it was to get those drill cores.
Deepwater drilling, too, has come a long way since 1970.
Last, the interest of this particular discovery applies to concerns about climate. It takes a long time to dry out a sea over a mile deep using nothing but sun and wind.
But it is now known that it happened over and over again, and within a comparatively short time, just a few million years.
Continents drift at a slow rate, but it turns out big seas can dry up quickly, and given nothing more than normal variation in inputs. The repeated drying and refilling of the Mediterranean was roughly coincident with the evolution of Homo from an ancestral non-humanoid primate.
Hsu's tale makes all the panic about climatic changes in the past thousand years sound like children being afraid of monsters under the bed.
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