Oligocene
Sign in to saveThe Oligocene is a geologic epoch of the Paleogene Period that extends from about 33.9 million to 23 million years before the present ( to ). 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 from his studies of marine beds in Belgium and Germany. The name comes from Ancient Greek ὀλίγος (olígos), , and καινός (kainós), , and refers to the sparsity of extant forms of molluscs. The Olig
AI overview
The Oligocene is a geologic epoch that lasted from about 33.9 million to 23 million years ago and is part of the broader Paleogene Period. The epoch is named after the relatively small number of mollusk species from that time that still exist today, and scientists have identified the rock layers that mark this period, though the exact dates remain slightly uncertain.
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Key facts
- Geologic timespan.name
- Oligocene
- Geologic timespan.color
- Oligocene
- Geologic timespan.time_start
- 33.9
- Geologic timespan.time_end
- 23.04
- Geologic timespan.image_map
- Mollweide Paleographic Map of Earth, 30 Ma (Rupelian Age).png
- Geologic timespan.caption_map
- A map of Earth as it appeared 30 million years ago during the Oligocene Epoch, Rupelian Age
- Geologic timespan.timeline
- Paleogene
- Geologic timespan.name_formality
- Formal
- Geologic timespan.name_accept_date
- 1978
- Geologic timespan.celestial_body
- earth
- Geologic timespan.usage
- Global (ICS)
- Geologic timespan.timescales_used
Article
23 sectionsContents
- Boundaries and subdivisions
- Tectonics and paleogeography
- Climate
- Eocene-Oligocene transition and Oi1 event
- Middle Oligocene climate and the Oi2 event
- Late Oligocene warming
- Biosphere
- Flora
- Fauna
- Oceans
- Effects of oceanic gateways on circulation
- Drake Passage
- Opening of the Tasman Gateway
- Tethys Seaway closing
- Greenland–Iceland–Faroes
- Ocean cooling
- Deep water
- Impact events
- Supervolcanic explosions
- See also
- Notes
- References
- External links
The Oligocene is a geologic epoch of the Paleogene Period that extends from about 33.9 million to 23 million years before the present ( to ). 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 from his studies of marine beds in Belgium and Germany. The name comes from Ancient Greek ὀλίγος (olígos), , and καινός (kainós), , 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. Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forests to the equatorial belt.