Meteor impact may have plunged world into Ice Age 2.5 million years ago

When a huge meteor collided with Earth about 2.5 million years ago and fell into the southern Pacific Ocean it not only could have generated a massive tsunami but also may have plunged the world into the Ice Age, Australian researchers suggest.

They say that because the Eltanin meteor – which was up to two kilometres across - crashed into deep water, most scientists have not adequately considered either its potential for immediate catastrophic impacts on coastlines around the Pacific rim or its capacity to destabilise the entire planet’s climate system.

“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,” said Professor James Goff, lead author of a paper describing the study.

Goff is co-director of UNSW’s Australia-Pacific Tsunami Research Centre and Natural Hazards Research Laboratory.

In the paper, Goff and colleagues from UNSW and the Australian Nuclear Science and Technology Organisation, noted that geologists and climatologists have interpreted geological deposits in Chile, Antarctica, Australia, and elsewhere as evidence of climatic change, marking the start of the Quaternary period. An alternative interpretation is that some or all of these deposits may be the result of mega-tsunami inundation, the study suggests.

“There’s no doubt the world was already cooling through .the mid and late Pliocene. 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,” said co-author Professor Mike Archer.

“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. 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,” he added.

The paper will appear in the Journal of Quaternary Science.