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.

When we talk about mass extinction events ... Earth about 66 million years ago and triggered the extinction of the dinosaurs. However, the Cretaceous–Paleogene extinction event was not the ...

Today’s extinction rates are sky-high. But scientists debate if that’s sufficient evidence to conclude that Earth is undergoing a mass extinction event—or ... s depiction of marine life during the ...

about 66 million years ago at the end of the Cretaceous Period. There is consensus among scientists that the mass extinction was caused by the impact of a large asteroid or comet that hit the ...

That individual animal lived not so long before the Cretaceous-Tertiary extinction that wiped out many of Earth's species some 65 million years ago. Brachychampsa had short teeth and a large mouth ...

A gradual decline in the number of dinosaur species would likely mirror an equally gradual cause of their ultimate extinction ... leading up to the end of the Cretaceous. Sea Level The presence ...