K-Pg boundary
Extinction event marker
The K-Pg boundary is the geological boundary marking the mass extinction event 66 million years ago that ended the Cretaceous period and began the Paleogene.
This boundary layer, visible in rock formations worldwide, contains high concentrations of iridium—evidence of the asteroid impact that killed the dinosaurs and roughly three-quarters of all species.
Formerly called the K-T boundary (Cretaceous-Tertiary).
- shocked quartzImpact-deformed silica mineral
- dinosaur fossilsPreserved prehistoric reptile remains
- ammonitesExtinct coiled-shell cephalopods
- PaleogeneEarly Cenozoic era division
- CretaceousFinal Mesozoic period
Alvarez · ferns · microfossils · iridium · Yucatan · trace elements · dinosaurs · mass extinction · asteroid · marine reptiles · ejecta · Jurassic · mammals · crater · layer · fireball · sediment · Deccan Traps
- extinctionmass extinction, dodo, extinct, extinction event, extinction rate
- Mesozoicdinosaurs, Velociraptor, Brachiosaurus, Spinosaurus, pterosaurs
- Cretaceous PeriodVelociraptor, hadrosaur, ceratopsian, titanosaur, Albertosaurus
- CenozoicPaleocene, Miocene, Pliocene, Pleistocene, Holocene
- Cretaceous Geology
- AlvarezNobel Prize, physicist, iridium layer, dinosaur extinction, asteroid impact