Cretaceous
Third and last period of the Mesozoic Era, 145-66 million years ago / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Cretaceous?
Summarize this article for a 10 years old
The Cretaceous (IPA: /krɪˈteɪʃəs/ krih-TAY-shəs)[2] is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation Kreide.
| Cretaceous | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| ~145.0 – 66.0 Ma | |||||||||
A map of the world as it appeared during the Early Cretaceous, c. 105 Ma | |||||||||
| Chronology | |||||||||
| |||||||||
| Etymology | |||||||||
| Name formality | Formal | ||||||||
| Usage information | |||||||||
| Celestial body | Earth | ||||||||
| Regional usage | Global (ICS) | ||||||||
| Time scale(s) used | ICS Time Scale | ||||||||
| Definition | |||||||||
| Chronological unit | Period | ||||||||
| Stratigraphic unit | System | ||||||||
| Time span formality | Formal | ||||||||
| Lower boundary definition | Not formally defined | ||||||||
| Lower boundary definition candidates |
| ||||||||
| Lower boundary GSSP candidate section(s) | None | ||||||||
| Upper boundary definition | Iridium-enriched layer associated with a major meteorite impact and subsequent K-Pg extinction event | ||||||||
| Upper boundary GSSP | El Kef Section, El Kef, Tunisia 36.1537°N 8.6486°E / 36.1537; 8.6486 | ||||||||
| Upper GSSP ratified | 1991 | ||||||||
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice-free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
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. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Oops something went wrong: