Scientists have discovered levels of iridium 30 times greater than average in the Cretaceous/Tertiary (KT) boundary, the layer of sedimentary rock laid down at the time of the dinosaur extinction.

You might know the Cretaceous Period for big animals such as Tyrannosaurus rex and Triceratops, or for being the end of the age of dinosaurs. But what was the world like in the millions of years ...

The Cretaceous-Paleogene (K-Pg) extinction event that occurred 66 million years ago is believed to have been caused by an asteroid crashing into Earth just off the Yucatan peninsula in south ...