The rock that records the end of the dinosaurs

Scientists tell us there was an asteroid strike 66 million years ago that wiped three-quarters of all species from the surface of the Earth. The impact ended the reign of the dinosaurs and ushered in the rise of mammals.

Geologists call the older period the Cretaceous; the younger period is referred to as the Paleogene. The boundary between the two - the Cretaceous-Paleogene (K-Pg) boundary - is written in rocks around the world. Prof Phil Manning from the University of Manchester showed a sample of rock containing the boundary to our science editor Rebecca Morelle.

Read more: 'First dinosaur fossil linked to asteroid strike'