Dating of rock formation in New Mexico casts doubt on theory that species was already in decline
Dinosaurs would not have become extinct had it not been for a catastrophic asteroid strike, researchers have said, challenging the idea the animals were already in decline.
About 66m years ago, during the late Cretaceous period, a huge space rock crashed into Earth, triggering a mass extinction that wiped out all dinosaurs except birds. However, some experts have argued the dinosaurs were already in decline.
