Volcanic activity did for the dinosaurs

Asteroid simply the last straw, study suggests

The dinosaurs might have been wiped out by a huge volcanic eruption, a new study suggests, rather than an asteroid strike 65m years ago, as is widely believed.

The possibility of a volcanic catastrophe being behind the fall of the great reptiles has long been mooted: the Deccan Traps in India are evidence of a series of huge volcanic eruptions that have been dated to around 65m years ago, the same time as the dinosaurs vanished from the Earth.

The eruptions would have sent massive quantities of ash and sulphur dioxide into the atmosphere, enough to have a significant impact on the climate, and possibly doom the terrible lizards.

However, until now, the eruptions were thought to have taken place sporadically, over the course of several million years. This would have given the environment and climate plenty of time to adjust, and has always made the asteroid strike the more likely candidate for the dinosaurs' sudden extinction.

The new study, conducted by scientists at the Institut de Physique du Globe de Paris, suggests that much of the volcanic activity too place within a relatively short period of time - perhaps as little as 30,000 years, The Independent reports.

by studying the magnetisation of the lava, the researchers are able to estimate how the time period over which it solidified. They discovered that in 30,000 years a 660m thick layer of lava was deposited. This would have been accompanied by enough sulphur dioxide to alter the climate, and to alter the PH of the seas.

The arrival of the asteroid 65m years ago was just the icing on the cake.

"Paleontologists say the decline in the dinosaurs began long before the Chicxulub impact. We would argue that they were being poisoned due to the Deccan Traps," Dr. Mike Widdowson, a volcanologist from the Open University in Milton Keynes, told the paper. ®