|Regional usage||Global (ICS)|
|Time scale(s) used||ICS Time Scale|
|Time span formality||Formal|
|Lower boundary definition|
|Lower boundary GSSP||Lemme-Carrosio Section, Carrosio, Italy|
|Lower GSSP ratified||1996|
|Upper boundary definition|
|Upper boundary GSSP||Monte San Nicola Section, Gela, Sicily, Italy|
|Upper GSSP ratified||2009 (as base of Quaternary and Pleistocene)|
|Atmospheric and climatic data|
|Mean atmospheric O2 content||c. 21.5 vol %|
(108 % of modern)
|Mean atmospheric CO2 content||c. 280 ppm|
(1 times pre-industrial)
|Mean surface temperature||c. 14 °C|
(0 °C above modern)
The Neogene (// NEE-ə-jeen, informally Upper Tertiary or Late Tertiary) 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. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868).
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. 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 follows.
tucker-2001was 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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