Definition of Archean in English:

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Pronunciation: /ärˈkēən/
(British Archaean)


1Relating to or denoting the eon that constitutes the earlier (or middle) part of the Precambrian, in which there was no life on earth. It precedes the Proterozoic eon. Also called azoic.
Example sentences
  • The answers to questions about early life on Earth are preserved in the oldest rocks, and Canadian earth scientists include some of the world's best Archean geologists and laboratories equipped to study Archean rocks.
  • The geological history of Archaean greenstone belts is controversial and, to date, no tectonic model for their evolution has been agreed upon.
  • The contacts between the complex and the Archaean metamorphic rocks are intrusive.
1.1 (as noun the Archean) The Archean eon or the system of rocks deposited during it.

The Archean extended from the origin of the earth (see Precambrian) to about 2,500 million years ago. In models that include the Priscoan eon, the Archean began about 4,000 million years ago.


Late 19th century: from Greek arkhaios 'ancient' + -an.

For editors and proofreaders

Syllabification: Ar·che·an

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