Share this entry

Share this page

Archaean

Line breaks: Ar|chaean
Pronunciation: /ɑːˈkiːən
 
/
(US Archean)

Definition of Archaean in English:

adjective

Geology
1Relating to or denoting the aeon that constitutes the earlier (or middle) part of the Precambrian, in which there was no life on the earth. It precedes the Proterozoic aeon and (in some schemes) is preceded by the Priscoan aeon. Also called the 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 Archaean) The Archaean aeon or the system of rocks deposited during it.

The Archaean extended from the origin of the earth (see Precambrian) to about 2,500 million years ago. In schemes which include the Priscoan aeon, the Archaean began about 4,000 million years ago

Origin

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

Definition of Archaean in:

Share this entry

Share this page

 

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day terpsichorean
Pronunciation: ˌtəːpsɪkəˈriːən
adjective
relating to dancing