Archaean

  1. Adjective.  (geology) of, or relating to the geologic eon from about 3,800 to 2,500 million years ago; comprises the Eoarchean, Paleoarchean, Mesoarchean and Neoarchean eras; marked by an atmosphere with little oxygen, the formation of the first continents and oceans and the emergence of simple life.
  2. Proper noun.  (geology) the Archaean eon.

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This entry was last updated on RefTopia from its source on 3/20/2012.