Oligocene
Americanadjective
noun
adjective
noun
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The third epoch of the Tertiary Period, from about 37 to 24 million years ago. During this time there was an increase in volcanic activity, and Australia and South America separated from Antarctica. The climate started to cool and a glacier started to form in Antarctica. Modern mammalian groups continued to develop, and the first cats, dogs, horses, and related mammals appeared. Artiodactyls (even-toed ungulates) took over from the perissodactyls (uneven-toed ungulates) as the dominant medium-sized herbivores. Many types of grass also first appeared at this time.
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See Chart at geologic time
Other Word Forms
Etymology
Origin of Oligocene
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The Gibraltar arc formed in the Oligocene as a part of the Western Mediterranean subduction zones.
From Science Daily ● Feb. 15, 2024
The report includes an understated, but nonetheless pointed, criticism of the paltriness of scientific literature about North Pacific odontocetes species from the Oligocene epoch, which lasted roughly from 33.7 to 23.8 million years ago.
From Salon ● Jun. 24, 2023
Based on the location and age of the rocks surrounding the ant hills, the researchers estimate that the fossils are from the late Eocene and early Oligocene epochs.
From New York Times ● Jul. 1, 2022
The early fossil record of the group is poor, with the oldest specimen being from the Late Oligocene of Australia.
From Scientific American ● Apr. 8, 2018
The shells which have been found in them indicate that they belong for the most part to the Oligocene period.
From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" by Various
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