Oligocene Epoch
E252484
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.
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 Epoch
ⓘ
linked to:
Miocene
|
| follows |
Eocene Epoch
ⓘ
linked to:
Eocene
|
| geochronologicEquivalent |
Oligocene Series
ⓘ
linked to:
Oligocene Epoch
|
| 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 Period
ⓘ
linked to:
Paleogene
|
| 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
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Oligocene Epoch Description of subject: 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.
Referenced by (9)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Oligocene Epoch
linked to: Oligocene Epoch
linked to: Oligocene Epoch
linked to: Oligocene Epoch
linked to: Oligocene Epoch
linked to: Oligocene Epoch
linked to: Oligocene Epoch