Scientists Claim Evidence Of Comet-Impact Megatsunamis Causing 600-Foot-Tall Waves; Furthermore Claim Such Impacts Are Relatively Common

Surf's up, baby. This is a NYT link, but you might want to break your embargo, if such things interest you.

Thick deposits of what seem to be large swaths from the ocean's floor are scattered at various places on dry land. How did big parts of the sea-bed wind up on land?

At the southern end of Madagascar lie four enormous wedge-shaped sediment deposits, called chevrons, that are composed of material from the ocean floor. Each covers twice the area of Manhattan with sediment as deep as the Chrysler Building is high.

On close inspection, the chevron deposits contain deep ocean microfossils that are fused with a medley of metals typically formed by cosmic impacts. And all of them point in the same direction — toward the middle of the Indian Ocean where a newly discovered crater, 18 miles in diameter, lies 12,500 feet below the surface.

The explanation is obvious to some scientists. A large asteroid or comet, the kind that could kill a quarter of the world’s population, smashed into the Indian Ocean 4,800 years ago, producing a tsunami at least 600 feet high, about 13 times as big as the one that inundated Indonesia nearly two years ago. The wave carried the huge deposits of sediment to land.

...

Deposits from mega-tsunamis contain unusual rocks with marine oyster shells, which cannot be explained by wind erosion, storm waves, volcanoes or other natural processes, Dr. Bryant said.

“We’re not talking about any tsunami you’re ever seen,” Dr. Bryant said. “Aceh was a dimple. No tsunami in the modern world could have made these features. End-of-the-world movies do not capture the size of these waves. Submarine landslides can cause major tsunamis, but they are localized. These are deposited along whole coastlines.”

And the great thing is that if they're right (which, by the way, other scientists doubt), it means that extinction-level cosmic impacts occur every several thousand years, rather than every half-millon to million years as most astronomers now believe.

A little perspective, then. Does it really matter if Nancy Pelosi is Speaker of the House when the human race will be either extinct or reduced to stone-age primativism in short order anyway?

posted by Ace at 02:29 PM

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