• Home

Big meteor strike killed all dinosaurs

A new German-led study has marshalled even more powerful evidence that a single meteor strike 65 million years ago led to the sudden extinction of all the earth's dinosaurs.

That theory has dominated dinosaur studies for a couple of decades, but has remained unproven, with some dissidents saying a monstrous volcanic eruption in India caused the extinction.

Peter Schulte of the University of Erlangen and Nuremberg said evidence turned up by scientists in recent years indicated the impact on what is now the Yucatan peninsula of Mexico was the cause.

The review by 41 scientists was published Thursday in the journal Science.

"When one assembles all the new information we have got in the recent past, the single big impact explanation is the only one that holds up," said Schulte. "But we don't have exact proof, and perhaps we never will," he added.

The impact site, the Chicxulub Crater, is 200 km across. The scientists say earthquakes and tsunamis killed every living thing in a radius of 1,500 km. The fossil record shows two thirds of earth's flora and fauna died out after the impact.

The projectile was 10,000 metres across and hit at about 20 times the velocity of a rifle bullet.

"The most fatal effect was what happened afterwards: the huge amount of dust and soot that got into the atmosphere. At the same time, a vast amount of sulphur from rock beneath the peninsula escaped," Schulte explained.

The murky skies stopped sunlight reaching the earth for several years and the world cooled.

"That wrecked many of the food chains," said Schulte, pointing to evidence of massive decline in oceanic plankton populations and the death of forests. That killed off herbivorous, leaving no food for meat-eaters.