The K-T boundary

The K-T boundary marks a global geological transition about 66 million years ago, signaling the end of the Cretaceous period and the beginning of the Paleogene period. It is most famous for coinciding with a mass extinction event that wiped out about 75% of species, including the dinosaurs. This boundary is identified by a layer of clay enriched with iridium, a rare metal often associated with asteroids. Scientific evidence strongly supports that a large asteroid impact caused widespread environmental disruption, leading to the mass extinction. The K-T boundary is crucial for understanding Earth's history and the causes of major biological changes.