What is Eocene?

  • (noun): From 58 million to 40 million years ago; presence of modern mammals.
    Synonyms: Eocene epoch


The Eocene (symbol EO) epoch, lasting from about 56 to 34 million years ago (55.8±0.2 to 33.9±0.1 Ma), is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by the emergence of the first modern mammals. The end is set at a major extinction event called the Grande Coupure (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the epoch are well identified, though their exact dates are slightly uncertain.

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Some articles on Eocene:

... America and Eurasia during the late Paleocene and most of the Eocene ... They went extinct in Europe during the early Eocene, while North American and Asian forms survived until the middle Eocene ... tillodonts lived in China and disappeared during the late Eocene ...
Eocene–Oligocene Extinction
... The end of the Eocene was marked by the Eocene–Oligocene extinction event, also known as the Grande Coupure ...
Cypselomorphae - Systematics - Evolution
... The relationships of the Early Eocene Parvicuculus and Procuculus from the southern North Sea basin are unresolved, but they bear some similarities to cypselomorphs ... here as basal or incertae sedis Eocypselus (Late Paleocene or Early Eocene) Paraprefica (Early Eocene?) Archaeotrogonidae (Early Eocene of England ?- Late Eocene/Early Oligocene of France ...
Carnivoramorpha - Evolution
... their way toward their maximum speciation, which occurred in the middle Eocene era (Stiles, 2005) ... In North America few creodonts survived past the Eocene, and all were extinct by the late Oligocene ... The taxonomic decline of Creodonta at the end of the Eocene coincided with the beginning of the speciation and radiation of the Carnivora, and the origination of most modern carnivore families ...
... polyodon, is from the Eocene-age Bridger Formation of Wyoming it is based on fossils that are difficult to distinguish from other Paleogene alligatorids ... heterodon is from the Eocene-age Wasatch Formation of Wyoming, A ... wartheni is from the Eocene-age Wildwood Formation (also known as the "Wildwood alligatorid," and possibly two species), and A ...