Oligocene Epoch

E252484

chronostratigraphic unit geologic epoch

The Oligocene Epoch was a geologic time interval roughly 34 to 23 million years ago marked by global cooling, the expansion of grasslands, and significant evolution and diversification of mammals.

Try in SPARQL Jump to: Surface forms Disambiguation Statements Elicitation Referenced by

All labels observed (3)

Label	Occurrences
Oligocene	7
Oligocene Epoch canonical	1
Oligocene Series	1

How this entity was disambiguated

This entity first appeared as the object of triple T2254442 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.

NED1 Entity disambiguation (via context triple) gpt-5-mini-2025-08-07

Target entity: Oligocene Epoch
Context triple: [Eocene–Oligocene climate transition, separates, Oligocene Epoch]

A. Pliocene epoch
The Pliocene epoch was a geological time period roughly 5.3 to 2.6 million years ago marked by cooler global climates, the expansion of grasslands, and significant evolutionary developments among mammals and early hominins.
B. Paleogene
The Paleogene is a geologic period that marks the beginning of the Cenozoic Era, characterized by the diversification of mammals and birds following the mass extinction that ended the age of dinosaurs.
C. Pridoli Epoch
The Pridoli Epoch is the final epoch of the Silurian Period, marking a transitional interval in Earth’s history just before the onset of the Devonian.
D. Pleistocene epoch
The Pleistocene epoch was a geological time period characterized by repeated ice ages, widespread glaciation, and the evolution and global spread of modern humans.
E. Neogene
The Neogene is a geologic period of the Cenozoic Era characterized by significant climatic cooling, the diversification of mammals and birds, and the emergence and evolution of early hominins.
F. None of above. chosen
G. Unsure - the case is ambiguous/there is not enough information to decide.

NED2 Entity disambiguation (via description) gpt-5-mini-2025-08-07

Target entity: Oligocene Epoch
Target entity description: The Oligocene Epoch was a geologic time interval roughly 34 to 23 million years ago marked by global cooling, the expansion of grasslands, and significant evolution and diversification of mammals.

A. Pliocene epoch
The Pliocene epoch was a geological time period roughly 5.3 to 2.6 million years ago marked by cooler global climates, the expansion of grasslands, and significant evolutionary developments among mammals and early hominins.
B. Paleogene
The Paleogene is a geologic period that marks the beginning of the Cenozoic Era, characterized by the diversification of mammals and birds following the mass extinction that ended the age of dinosaurs.
C. Pridoli Epoch
The Pridoli Epoch is the final epoch of the Silurian Period, marking a transitional interval in Earth’s history just before the onset of the Devonian.
D. Pleistocene epoch
The Pleistocene epoch was a geological time period characterized by repeated ice ages, widespread glaciation, and the evolution and global spread of modern humans.
E. Neogene
The Neogene is a geologic period of the Cenozoic Era characterized by significant climatic cooling, the diversification of mammals and birds, and the emergence and evolution of early hominins.
F. None of above. chosen

Statements (49)

Predicate	Object
instanceOf	chronostratigraphic unit ⓘ geologic epoch ⓘ
baseDefinedBy	extinction of planktonic foraminifer Hantkenina ⓘ
characterizedBy	continued breakup of Gondwana-derived landmasses ⓘ development of modern-type ecosystems ⓘ diversification of mammals ⓘ expansion of grasslands ⓘ global cooling ⓘ
climate	generally cooler and drier than Eocene ⓘ
climateEvent	Antarctic glaciation expansion ⓘ strengthening of latitudinal temperature gradients ⓘ
climateTrend	cooling relative to Eocene ⓘ
duration	about 11 million years ⓘ
end	approximately 23.03 million years ago ⓘ
fauna	decline of many archaic mammal groups ⓘ diversification of early cetaceans ⓘ diversification of early primates ⓘ diversification of early rodents ⓘ diversification of marine invertebrates ⓘ evolution of early ruminants ⓘ evolution of more modern-type horses ⓘ presence of large browsing mammals ⓘ radiation of early carnivorans ⓘ
flora	decline of some tropical forests at mid-latitudes ⓘ early spread of grasses ⓘ expansion of open woodlands ⓘ
followedBy	Miocene ⓘ surface form: Miocene Epoch
follows	Eocene ⓘ surface form: Eocene Epoch
geochronologicEquivalent	Oligocene Epoch self-linksurface differs ⓘ surface form: Oligocene Series
GSSPDefinedBy	base at Massignano, Italy ⓘ
nameCoined	1854 ⓘ
namedBy	Heinrich Ernst Beyrich ⓘ
nameEtymology	from Greek words meaning "few" and "recent" ⓘ
oceanography	development of Antarctic Circumpolar Current ⓘ
paleogeography	continued opening of the North Atlantic ⓘ development of more modern continental configurations ⓘ increasing isolation of Antarctica ⓘ
partOf	Paleogene ⓘ surface form: Paleogene Period
positionInCenozoic	third epoch of the Cenozoic Era ⓘ
positionInPaleogene	final epoch of the Paleogene Period ⓘ
seaLevel	generally lower than in Eocene ⓘ
significance	important stage in evolution of modern mammal faunas ⓘ transition toward modern Cenozoic climates ⓘ
start	approximately 33.9 million years ago ⓘ
subdivision	Early Oligocene ⓘ Late Oligocene ⓘ
tectonics	continued uplift of the Alps ⓘ continued uplift of the Himalayas ⓘ rifting and volcanism in East Africa ⓘ

How these facts were elicited