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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.
c. 2.58 Ma – start of the Pleistocene epoch, the Stone Age and the current Quaternary Period; emergence of the genus Homo. Smilodon, the best known of the sabre-toothed cats, appears. c. 2.4 Ma – The Amazon River takes its present shape in South America. c. 2.0–1.5 Ma – The basin of the Congo River acquires its present shape.
In 1978, the Paleogene was officially defined as the Paleocene, Eocene, and Oligocene Epochs; and the Neogene as the Miocene and Pliocene Epochs. [12] In 1989, Tertiary and Quaternary were removed from the time scale due to the arbitrary nature of their boundary, but Quaternary was reinstated in 2009.
PEMEX began drilling into the unusual ring-like structure under the Yucatan and extracting rock cores in search of oil. [24] 1962. Stanley E. Flanders suggested that at the end of the Cretaceous caterpillars began multiplying until they had so denuded the contemporary plant life that nothing was left for the dinosaurs, who starved to death. [19 ...
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.
1980 — Luis Alvarez, Walter Alvarez, Frank Asaro, and Helen Michel propose the Alvarez hypothesis, that a comet or asteroid struck the Earth 66 million years ago causing the Cretaceous–Paleogene extinction event, including the extinction of the non-avian dinosaurs, and enriching the iridium in the K–T boundary.
The Paleogene (alternatively Palaeogene) Period is a unit of geologic time that began 66 and ended 23.03 Ma [10] and comprises the first part of the Cenozoic Era. This period consists of the Paleocene , Eocene and Oligocene Epochs.
Mammal diversification truly began only after the Cretaceous-Paleogene extinction event. [185] By the early Paleocene the Earth recovered from the extinction, and mammalian diversity increased. Creatures like Ambulocetus took to the oceans to eventually evolve into whales, [ 186 ] whereas some creatures, like primates, took to the trees. [ 187 ]