Definition of Archean in English:

Archean

adjective

(British Archaean)
Geology
  • Relating to or denoting the eon that constitutes the earlier (or middle) part of the Precambrian, in which there was no life on the earth. It precedes the Proterozoic eon and (in some schemes) is preceded by the Priscoan eon.

    Also called azoic

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

    ‘the main basement rocks are Archeangneiss’
    • ‘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.’
    • ‘However, most Archean volcanic rocks occur as deformed and fault-fragmented packages termed greenstone belts.’
    • ‘Comparison of the ‘bar code’ from the approximately 35 different Archean continental fragments (at least eight of which are in Canada) represents a key tool for proposing reconstructions between these fragments.’

Pronunciation

Archean

/ärˈkēən/ /ɑrˈkiən/

noun

(British Archaean)
Geology
  • the ArcheanThe eon that constitutes the earlier (or middle) part of the Precambrian 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 chronological arrangements which include the Priscoan eon, the Archean began about 4,000 million years ago

    • ‘these organisms evolved sometime near the onset of the Archean’

Pronunciation

Archean

/ärˈkēən/ /ɑrˈkiən/

Origin

Late 19th century from Greek arkhaios ‘ancient’+ -an.