Did a crashing meteor kick-start Ice Ages?

A gigantic meteor collided with the earth about 2.5 million years ago, generating the mother of all tsunamis, hundreds of metres high, possibly plunging the planet into the Ice Ages, an Australian study says. Most scientists may have overlooked Eltanin meteor's potential for immediate catastrophic impact, or its capacity to destabilize the entire planet's climate system, when the 2,000 metre object crashed in the southern Pacific Ocean.

"This is the only known deep-ocean impact event on the planet and its largely been forgotten because there's no obvious giant crater to investigate, as there would have been if it had hit a landmass," says James Goff, professor at The University of New South Wales' (UNSW) Australia-Pacific Tsunami Research Centre. Goff led the study. "But consider that we're talking about something the size of a small mountain crashing at very high speed into very deep ocean, between Chile and Antarctica," adds Goff, the Journal of Quaternary Science reports.

A meteor could have been the cause of the Ice Ages (image credit: Wikipedia)

"Unlike a land impact, where the energy of the collision is largely absorbed locally, this would have generated an incredible splash with waves literally hundreds of metres high near the impact site," adds Goff. "Some modelling suggests that the ensuing mega-tsunami could have been unimaginably large - sweeping across vast areas of the Pacific and engulfing coastlines far inland. But it also would have ejected massive amounts of water vapour, sulphur and dust up into the stratosphere."

"The tsunami alone would have been devastating enough in the short term, but all that material shot so high into the atmosphere could have been enough to dim the sun and dramatically reduce surface temperatures," Goff said. "Earth was already in a gradual cooling phase, so this might have been enough to rapidly accelerate and accentuate the process and kick start the Ice Ages," concludes Goff.

"There's no doubt the world was already cooling through the mid and late Pliocene Epoch," says study co-author Mike Archer, professor and Goff's colleague. "What we're suggesting is that the Eltanin impact may have rammed this slow-moving change forward in an instant - hurtling the world into the cycle of glaciations that characterized the next 2.5 million years and triggered our own evolution as a species," Archer said.

IANS