Miocene

[mahy-uh-seen]

adjective

1. noting or pertaining to an epoch of the Tertiary Period, occurring from 25 to 10 million years ago, when grazing mammals became widespread.

noun

1. the Miocene Epoch or Series.

Miocene

/ ˈmaɪəˌsiːn /

adjective

1. of, denoting, or formed in the fourth epoch of the Tertiary period, between the Oligocene and Pliocene epochs, which lasted for 19 million years

noun

1. this epoch or rock series

Miocene

1. The fourth epoch of the Tertiary Period, from about 24 to 5 million years ago. During this time the climate was warmer than it had been in the Oligocene, and kelp forests and grasslands first developed. With the isolation of Antarctica, a circumpolar ocean current was established in the southern Hemisphere, reducing the amount of mixing of cold polar water and warm equatorial water and causing a buildup of ice sheets in Antarctica. The African-Arabian plate became connected to Asia, closing the seaway which had previously separated Africa from Asia. Mammalian diversity was at its peak.

2. See Chart at geologic time

Other Word Forms

• post-Miocene adjective

Word History and Origins

Origin of Miocene¹

First recorded in 1825–35; mio- (from Greek meíōn “less”) + -cene

Word History and Origins

Origin of Miocene¹

C19: from Greek meiōn less + _-cene

Example Sentences

The Tatacoa Desert is home to rich deposits of fossils from an epoch known as the Middle Miocene.

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In a paper published January 2025, Reichgelt and collaborator Christopher West compared the shapes of fossil leaves of the Miocene gathered and analyzed in many previous studies with a dataset of modern leaf morphologies.

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The fossils dating to the Miocene were encased in a type of fossilized algae called diatomite.

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Identifying how and why Antarctica's major ice sheets behaved the way they did in the early Miocene could help inform understanding of the sheets' behavior under a warming climate.

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The work is described by the editors as fundamental to our understanding of how the elongated lower jaw and long trunks evolved in these animals during the Miocene epoch, around 11-20 million years ago.

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