The Hindu : National : Some theories on extinction

Online edition of India's National Newspaper
Friday, Oct 29, 2004

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National

Some theories on extinction

By Dennis Marcus Mathew

HYDERABAD, OCT. 28. The dinosaurs are dead and gone, but the debate over their extinction still rages. And now, after over 100 theories in as many years, the latest is a volcanic hypothesis. According to this, the Deccan Traps, a flood basalt province in India, had a major role in the disappearance of dinosaurs and two-thirds of all other living species from the face of the earth some 65 million years ago.

Vincent Courtillot, director of the Institute of Physics at the University of Paris, is among those who believe that volcanic eruptions had a hand in the extinction. Mr. Courtillot does not rule out the meteorite impact theory put forward by the Nobel laureates Walter and Luis W. Alvarez in 1980, but suggests that both the meteorite impact and volcanic eruptions, leading to a nuclear-like winter situation on the earth, did it. The meteor, he says, was only the last straw that broke the dinosaur's back.

Mr. Courtillot seeks to debunk certain myths surrounding one of the most controversial arguments in science, including Darwin's Theory of Evolution with its premise of the survival of the fittest.

Speaking to a select audience at the University of Hyderabad here on Sunday, Mr. Courtillot said the mass extinction could be attributed to climatic events related to outpouring of lava from the Deccan Traps 65 million years ago. That phase coincided with the extinction of dinosaurs. That intensive period of volcanic eruptions included those in the Siberian Traps and the Karoo-Ferrar Province. Stressing that the Chicxulub crater, 1,500 metres beneath Mexico's Yucatan peninsula where the meteor landed, is not the only reason behind the extinctions, Mr. Courtillot said: "Something major happened 250 million years ago, leaving behind just one per cent of what was there on the earth. Something similar happened 200 million years ago, and again, on a larger scale, 65 million years ago. But life today is the result of the one per cent that survived the first mass extinction."

The crater impact, according to Mr. Courtillot, was proved by American micro-palaeontologist Greta Keller to have occurred 3,00,000 years ago, before the dinosaurs died. Then there are oceanic anoxic events that resulted in the continental drift, which he described as the ballet of continents. All these — the meteor, the volcanoes, the ballet — have some relation to the extinctions, he says.

Mr. Courtillot was here to deliver one of a series of lectures by academics annually organised at the University of Hyderabad.

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