Neogene | |||||||||||
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![]() Map of Earth as it appeared 20 million years ago during the Miocene epoch, Burdigalian stage[citation needed] | |||||||||||
Chronology | |||||||||||
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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 |
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Lower boundary GSSP | Lemme-Carrosio Section, Carrosio, Italy 44°39′32″N 8°50′11″E / 44.6589°N 8.8364°E | ||||||||||
Lower GSSP ratified | 1996[4] | ||||||||||
Upper boundary definition |
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Upper boundary GSSP | Monte San Nicola Section, Gela, Sicily, Italy 37°08′49″N 14°12′13″E / 37.1469°N 14.2035°E | ||||||||||
Upper GSSP ratified | 2009 (as base of Quaternary and Pleistocene)[5] | ||||||||||
Atmospheric and climatic data | |||||||||||
Mean atmospheric O2 content | c. 21.5 vol % (100 % of modern) | ||||||||||
Mean atmospheric CO2 content | c. 280 ppm (1 times pre-industrial) | ||||||||||
Mean surface temperature | c. 14 °C (0.5 °C above pre-industrial) |
The Neogene (/ˈniː.ədʒiːn/ NEE-ə-jeen,[6][7]) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 million years ago. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary.[8] The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868).[9] The earlier term Tertiary Period was used to define the span of time now covered by Paleogene and Neogene and, despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use.[10]
During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans (Homo habilis) appeared in Africa near the end of the period.[11] Some continental movements took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the Gulf Stream to transfer heat to the Arctic Ocean. The global climate cooled considerably throughout the Neogene, culminating in a series of continental glaciations in the Quaternary Period that followed.
tucker-2001
was invoked but never defined (see the help page).From p. 806: "Das häufige Vorkommen der Wiener Mollusken … im trennenden Gegensatze zu den eocänen zusammenzufassen." (The frequent occurrence of Viennese mollusks in typical Miocene as well as in typical Pliocene deposits motivated me – in order to avoid the perpetual monotony [of providing] details about the deposits – to subsume both deposits provisionally under the name "Neogene" (νεος new and γιγνομαι to arise) in distinguishing contrast to the Eocene.)
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