Meteorite turned Mexico to mush

The meteorite that punctuated the age of the dinosaurs would have transformed a vast region of the Yucatan Peninsula into a seething fluid of pulverised rock, computer simulations have suggested.

Research by Gareth Collins at Imperial College, London, and colleagues at the University of Arizona, has indicated how the collision that blasted a hole at least 100km wide in Mexico some 65 million years ago may have made solid rock behave in hitherto unsuspected ways.

Their work sheds light on the strange formations found inside large impact craters, such as central peaks, terraced rim walls and even peak rings, recently found at Chicxulub.

One theory is that seismic energy from the passing shock wave formed in large collisions may transform the target into a sea of jostling granules.

Mr Collins's simulations suggest that if this were the case, the collapse of the excavated cavity could result in a ripple inside the crater, like dropping a sugar lump into a cup of tea. This would continue for some minutes before the seismic energy that keeps the particles animated is lost and the "ripple" is frozen, leaving behind the strange peak-ring formation.

"The simulations predict a towering central uplift within the crater that rises to a height more than three times that of Mount Everest before collapsing outwards in an immense tidal wave of rock debris," said Mr Collins.

An animation based on the simulation can be seen at: http://.huxley.ic.ac.uk/research/Comp&Geophys/Geophys/pro... P>