Asteroid was 'true culprit for dinosaur extinction'

Was it the asteroid or colossal volcanism that initiated the demise of the dinosaurs 66 million years ago? This has been a bit of a "to and fro" argument of late, but now a group of scientists has weighed in with what they claim is the definitive answer. The team has drawn its conclusions after studying sediments on the North Atlantic sea-floor. Prof Paul Wilson, from the University of Southampton, spoke to the Today programme on BBC Radio 4.