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Many of the dominant taxonomic groups present in modern times can be ultimately traced back to origins in the Cretaceous. During this time, new groups of mammals and birds appeared, including the earliest relatives of placentals & marsupials (Eutheria and Metatheria respectively), with the earliest crown group birds appearing towards to the end ...
c. 66.038 ± 0.011 Ma – Cretaceous-Paleogene extinction event at the end of the Cretaceous Period marks the end of the Mesozoic era and the age of the dinosaurs; start of the Paleogene Period and the current Cenozoic era.
A conference dedicated to the end-Cretaceous extinction event was held at Utah's Snowbird ski resort. [45] By this point in time, 36 K–T boundary sites with anomalously high iridium levels had been identified. [46] At the conference, Yale geochemist Karl Turekian disputed the impact hypothesis.
More than 80% of Cretaceous turtle species passed through the K–Pg boundary. All six turtle families in existence at the end of the Cretaceous survived into the Paleogene and are represented by living species. [101] Analysis of turtle survivorship in the Hell Creek Formation shows a minimum of 75% of turtle species survived. [102]
Tertiary (/ ˈ t ɜːr. ʃ ə. r i, ˈ t ɜː r. ʃ i ˌ ɛr. i / TUR-shə-ree, TUR-shee-err-ee) [1] is an obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the extinction of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at ...
End Triassic: 200 million years ago, 80% of species lost, including all conodonts; End Cretaceous: 66 million years ago, 76% of species lost, including all ammonites, mosasaurs, plesiosaurs, pterosaurs, and nonavian dinosaurs; Smaller extinction events have occurred in the periods between, with some dividing geologic time periods and
Deeper in time, a mass extinction event that ended the Devonian Period, a geological era when life thrived on land for the first time, was also attributed to a hyperthermal event likely triggered ...
The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) [a] occurred at the end of this age. [3] In this mass extinction , many commonly recognized groups such as non-avian dinosaurs , plesiosaurs and mosasaurs , as well as many other lesser-known groups, died out.