The Oligocene (IPA: /ˈɒlɪɡəsiːn,-ɡoʊ-/OL-ə-gə-seen, -goh-)[4] is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present (33.9±0.1 to 23.03±0.05 Ma). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich[5][6] from his studies of marine beds in Belgium and Germany.[7] The name comes from the Ancient Greek ὀλίγος (olígos, "few") and καινός (kainós, "new"),[8] and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.
The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene.[9] Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forests to the equatorial belt.
The start of the Oligocene is marked by a notable extinction event called the Grande Coupure; it featured the replacement of European fauna with Asian fauna, except for the endemic rodent and marsupial families. By contrast, the Oligocene–Miocene boundary is not set at an easily identified worldwide event but rather at regional boundaries between the warmer late Oligocene and the relatively cooler Miocene.
^Zachos, J. C.; Kump, L. R. (2005). "Carbon cycle feedbacks and the initiation of Antarctic glaciation in the earliest Oligocene". Global and Planetary Change. 47 (1): 51–66. Bibcode:2005GPC....47...51Z. doi:10.1016/j.gloplacha.2005.01.001.
^"International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
^Silva, Isabella; Jenkins, D. (September 1993). "Decision on the Eocene-Oligocene boundary stratotype" (PDF). Episodes. 16 (3): 379–382. doi:10.18814/epiiugs/1993/v16i3/002. Retrieved 13 December 2020.
^Beyrich (November 1854). "Über die Stellung der hessische Tertiärbildungen" [On the position of the Hessian Tertiary formations]. Verhandlungen Köngliche Preussischen Akademie Wissenschaft Berlin [Proceedings of the Royal Prussian Academy of Sciences at Berlin]: 640–666. From p. 664: "Der neue Name Oligocän mag sich zwischenstellen zwischen das ältere Eocän und das jüngere Miocän." (The new name Oligocene may be interposed between the older Eocene and the younger Miocene.)
^Wilmarth, Mary Grace (1925). Bulletin 769: The Geologic Time Classification of the United States Geological Survey Compared With Other Classifications, accompanied by the original definitions of era, period and epoch terms. Washington, D.C., U.S.: U.S. Government Printing Office. p. 53.
^Prothero 2005, p. 472.
^"Oligocene". Online Etymology Dictionary.
^Haines, Tim; Walking with Beasts: A Prehistoric Safari, (New York: Dorling Kindersley Publishing, Inc., 1999)
The Oligocene (IPA: /ˈɒlɪɡəsiːn, -ɡoʊ-/ OL-ə-gə-seen, -goh-) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million...
Cretaceous Period. This period consists of the Paleocene, Eocene, and Oligocene epochs. The end of the Paleocene (56 Mya) was marked by the Paleocene–Eocene...
particularly during the Paleocene–Eocene Thermal Maximum. However, the Eocene to Oligocene transition and the Quaternary glaciation dried and cooled Earth. Cenozoic...
the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the...
has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene...
geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between 33.9 and 27.82 Ma. It is preceded...
05 Ma to 15.97 ± 0.05 Ma (million years ago). It was preceded by the Oligocene epoch. As the climate started to get cooler, the landscape started to...
origin) and sometimes in Amphipithecidae, thought to originate in the Early Oligocene. Additionally, Phileosimias is sometimes placed in the Eosimiidae and...
geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between 27.82 and 23.03 Ma. The Chattian...
insects, birds, frogs and the tuatara. In the Duntroonian stage of the Oligocene, the land area of Zealandia was at a minimum. It has been suggested that...
hypercarnivorous diets that made them prone to extinction.: Fig. 1 By the Oligocene, all three subfamilies of canids (Hesperocyoninae, Borophaginae, and Caninae)...
from Oligocene with unclear systematic position. It was originally described from a jaw fragment for P. asiaticus, from Mongolia, Middle Oligocene. The...
forms and the emergence of cervids from the Oligocene to the early Pliocene. The latter half of the Oligocene (28–34 Mya) saw the appearance of the European...
and baleen-assisted mysticetes in the northwestern Pacific during the Oligocene. Nobile et al. (2024) describe fossil material of a member of the genus...
Neotethys formed during the Late Triassic and lasted in some form up to the Oligocene–Miocene boundary (about 24–21 million years ago) when it completely closed...
of the family Ekgmowechashalidae, known primarily from the Eocene and Oligocene of Asia. Notably, Palaeohodites has been recovered as the sister taxon...
terrestrial mammals that has ever existed and lived from the early to late Oligocene epoch (34–23 million years ago). The first fossils were discovered in...
Kekenodontidae is an extinct family of non-neocete pelagicetes from the Late Oligocene (Chattian) of New Zealand. Although at times classified as basal mysticetes...
Eocene/Early Oligocene) – anseranatid or anatid (own subfamily) Loxornis (Deseado Early Oligocene of Argentina) Paracygnopterus (Early Oligocene of Belgium...
Paraentelodon is an extinct entelodont from the Late Oligocene and Oligocene-Miocene boundary of Asia. The fossils of the type species P. intermedium...
Paleogene ruminants that lived in Europe from the late Eocene to the late Oligocene. The genus was erected in 1882 by Henri Filhol based on fossil remains...
Corumictis wolsani from the early and late Oligocene (early and late Arikareean, Ar1–Ar3) of Oregon. Middle Oligocene Mustelictis from Europe might be a mustelid...
of Forbidden City, USA) – phasianid? †"Palaeorallus" alienus (middle Oligocene of Tatal-Gol, Mongolia) †Anisolornis (Santa Cruz Middle Miocene of Karaihen...
lived in Eurasia and North America from the middle Eocene, throughout the Oligocene, to the early Miocene. Typical of early carnivorous mammals, individuals...
Global Information