K/T extinction event facts for kids
The Cretaceous–Tertiary extinction event, now called the Cretaceous–Palaeogene extinction event, was about 65.5 million years ago. It may be called the K/T extinction event or K/Pg event for short. This is the famous event which killed the dinosaurs at the end of the Cretaceous period.
Dinosaur fossils are only found below the K/T boundary. This shows they became extinct before, or during the event. Mosasaurs, plesiosaurs, pterosaurs and many species of plants and invertebrates also became extinct.
The K/T extinctions were so sudden and far-reaching that they must have been caused by something sudden and powerful. One or more massive asteroid or meteor impacts, and increased volcanic activity have been suggested.
How quickly animals died out around the world is an important clue. Patterns in rocks also suggest causes. There are several impact craters and massive volcanic activity in the Deccan Traps in India dated to about the same time as the extinctions. Those impacts and volcanoes would have reduced sunlight and hindered photosynthesis, disrupting Earth's ecology.
The best supported theory is that the meteorite strike in the Yucatan was the main cause of the extinction at the end of the Mesozoic era.
There were several impact events across the Cretaceous/Tertiary boundary, such as the Chicxulub crater in Mexico, Boltysh crater in Ukraine, Silverpit crater in North Sea, and the Shiva crater offshore western India. The Shiva crater is a sea floor structure under the continental shelf in the Indian Ocean, west of Mumbai, India. It was named by paleontologist Sankar Chatterjee after Shiva, the Hindu god of destruction and renewal.
Images for kids
An artist's rendering of an asteroid a few kilometers across colliding with the Earth. Such an impact can release the equivalent energy of several million nuclear weapons detonating simultaneously.
Discoscaphites iris ammonite from the Owl Creek Formation (Upper Cretaceous), Owl Creek, Ripley, Mississippi
The K–Pg boundary exposure in Trinidad Lake State Park, in the Raton Basin of Colorado, shows an abrupt change from dark- to light-colored rock. White line added to mark the transition.
Tyrannosaurus was among the dinosaurs living on Earth before the extinction.
K/T extinction event Facts for Kids. Kiddle Encyclopedia.