The Permian Extinction

Scientists believe they’ve solved the mystery of the Permian mass extinction 250 million years ago:

Scientists have located a massive crater under the Antarctic ice that they believe gave rise to the evolution of dinosaurs.
The 300-mile (480km) wide crater is thought to have been created by a meteor almost as big as London. It dates back 250 million years to the time of the biggest mass extinction in Earth’s history and the event that led to the first dinosaurs evolving.

Such was the catastrophic nature of the extinction that up to 96 per cent of all marine creatures were killed and 70 per cent of land animals. The strike may also have been powerful enough to have begun the break-up of the Gondwana supercontinent, which resulted in Australia sheering off and drifting northwards.

Researchers in the United States located the crater more than a mile beneath the East Antarctic ice sheet at Wilkes Land, using gravity measurements from satellites and radar images from aircraft. They calculated that it would take a meteor 30 miles wide to have caused such a crater. By comparison, the meteor held to have ended the dinosaur era and created the Chicxulub crater, in Mexico, would have been six miles across.

More here.