Dinosaur Extinction Layer (KT Boundary)

This vial contains a soil sample from the KT Boundary layer, scientifically known as the Cretaceous-Tertiary (K-T) Extinction Layer. First recognized by scientists in the 1980's then confirmed worldwide, this layer contains high levels of micro meteorites and the element iridium, which is extremely rare on Earth but abundant in asteroids.

In the early 1990's, a 180 kilometer (112 mile) wide crater was discovered in the Gulf of Mexico and helped to solidify the asteroid extinction theory. 75% of all species on Earth vanished, including the terrestrial and marine dinosaurs. This allowed for the evolutionary growth of smaller classes of species, especially mammals, which in the wake of the KT extinction became the dominant life on Earth.

Above: Satellite imagery of the Chicxulub impact crater in Mexico. Most scientists agree that this impact was the cause of the K-T Extinction.

This sample was collected in Slope County, North Dakota and has three layers. The bottom grey section is from the Cretaceous period, before the extinction of the dinosaurs, while the top brown section is the post-dinosaur Paleogene layer. The dark band in between is the KT Boundary itself.

Note: This layer is sometimes called the Cretaceous-Paleogene or K-Pg Boundary as well!