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The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out, widely thought to have been caused by the impact of a large asteroid that formed the Chicxulub crater in the Gulf of Mexico.
The Cretaceous–Paleogene (K–Pg) extinction event, [a] also known as the K–T extinction, [b] was the mass extinction of three-quarters of the plant and animal species on Earth [2] [3] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs.
The Cretaceous is the Phanerozoic's longest period and the last period of the Mesozoic. It spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous, and Late Cretaceous. [53] Tylosaurus, a type of large marine lizards known as mosasaurs
The Paleogene Period (IPA: / ˈ p eɪ l i. ə dʒ iː n,-l i. oʊ-, ˈ p æ l i-/ PAY-lee-ə-jeen, -lee-oh-, PAL-ee-; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 Ma (million years ago) to the beginning of the Neogene Period 23.04 Ma.
The Maastrichtian (/ m ɑː ˈ s t r ɪ k t i ə n / mahss-TRIK-tee-ən) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from .
In 1980, a team of researchers led by Nobel prize-winning physicist Luis Alvarez, his son, geologist Walter Alvarez, and chemists Frank Asaro and Helen Vaughn Michel, discovered that sedimentary layers found all over the world at the Cretaceous–Paleogene boundary (K–Pg boundary, formerly called Cretaceous–Tertiary or K–T boundary) contain a concentration of iridium hundreds of times ...
A study aiming to quantify the habitat of latest Cretaceous North American dinosaurs, based on data from fossil occurrences and climatic and environmental modelling, and evaluating its implications for inferring whether dinosaur diversity was in decline prior to the Cretaceous–Paleogene extinction event, was published by Chiarenza et al ...
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after creta, the Latin word for the white limestone known as chalk.