How A Giant Meteor Caused The Ice Age
A huge meteor collided with Earth 2.5 million years ago, causing a gigantic tsunami that swallowed everything in its path. But according to a new study, published in the Journal of Quaternary Science, the meteor impact may have had a much larger effect on the planet -- it may have ushered in the ice age.
Researchers from the University of New South Wales in Australia say that because the meteor, known as the Eltanin meteor, crashed in to the water, scientists have not properly considered its potential for catastrophic impact.
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"This is the only known deep-ocean impact event on the planet and it's largely been forgotten because there's no obvious giant crater to investigate, as there would have been if it had hit a landmass," Professor James Goff, study author, said in a statement. "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. 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."
The researchers constructed a model of the impact, and found that the tsunami would have been "unimaginably large," and would likely have engulfed coastlines and ejected water vapor, sulfur and dust into the atmosphere.
"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."
It's likely that the Earth was already beginning to cool when the meteor hit, and the large impact hastened it.
"There's no doubt the world was already cooling through the mid and late Pliocene," Professor Mike Archer, study coauthor, said in a statement. "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."
The researchers said the Eltanin meteor is as important as the meteor that wiped out the dinosaurs, in terms of history.
"As a 'cene' changer - that is, from the Pliocene to Pleistocene - Eltanin may have been overall as significant as the meteor that took out the non-flying dinosaurs 65 million years ago," Archer said. "We're urging our colleagues to carefully reconsider conventional interpretations of the sediments we're flagging and consider whether these could be instead the result of a mega-tsunami triggered by a meteor."
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