The Cretaceous-Tertiary mass extinction - also known as the K/T extinction - is famed for the death of the dinosaurs. However, many other organisms perished at the end of the Cretaceous including the ammonites, many flowering plants and the last of the pterosaurs. Some groups had been in decline for several million years before the final event that destroyed them all. It's suggested that the decline was due to flood basalt eruptions affecting the world's climate, combined with drastic falls in sea level. Then a huge asteroid or comet struck the seabed near the Yucatan Peninsula in Mexico and was the straw that broke the camel's back.
Global palaeogeographic reconstruction of the Earth at the time of the Cretaceous-Tertiary mass extinction. Credit: Dr Ron Blakey, NAU Geology.
At the end of the Cretaceous Period, 65 million years ago, all the dinosaurs died out. Why this happened is one of the most frequently asked - and intriguing - questions in palaeontology.
There have been many different ideas put forward to explain why the dinosuars died out. The two most likely are that their habitat slowly changed, and that a meteor impact triggered their extinction.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.