Before revision: Tanis fossil site In the 21st century, the discovery of the Tanis fossil site, ( a killing field ) in the Hell Creek formation of North Dakota, proved that the K-T boundary (now known as the KPg, or the Cretaceous–Paleogene extinction event) was the same event (the Chicxulub impact) which killed off the dinosaurs.
After revision: Tanis fossil site In the 21st century, the discovery of the Tanis fossil site, a killing field in the Hell Creek formation of North Dakota, proved that the K-T boundary (now known as the KPg, or the Cretaceous–Paleogene extinction event) was the same event (the Chicxulub impact) which killed off the dinosaurs.