archaean
IPA: ɑrkiʌn
Root Word: Archaean
noun
- (geology) The eon from 2,500 Ma to 4,000 Ma.
- (biology) Any organism of the domain Archaea.
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.
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Examples of "archaean" in Sentences
- An 'archaean' is a division of living beings, not a historical people.
- The subject of the photograph is the red archaean colonies growing on the salt crystals, not the salt crystals, themselves.
- Clark turned to his office, still contemplating the dignity of his visitor, the stark simplicity of this archaean aristocrat.
- Nor does it cease till the progress of the warmer day removes the northern ice-dam, sets free the flood, and the region of archaean rocks stands bare and dry.
- The Philadelphians took to the homeward trail with backward glances and something of regret lest the archaean foundations of that mountain of ore might shift over night.
- Your thirty-three page manuscript combines the brilliance of a young Marcus Paulk with the creative writing of Pierre Deligne, and will surely be devoured by archaean readers everywhere you send it.
- All this is of historic record in stony cypher of geology indelibly engraved by time on the rocky walls of deepest canyons, as traceable from the primordial archaean to our present era, the age of man.
- Originally an archaean sea-bottom rock this stone lay submerged in the ocean until during the Jurassic Period, under the lateral pressure of a cooling earthcrust the table-lands and mountain-chains of Arizona rose from the seas.
- Thus, the argument of Vestigian et al. 2006 that the universal genetic code did not originate in a frozen accident (in an actual cell), but arose communally, entails that n instances of the universal code (say, in H. sapiens, E. coli, and any archaean) do not indicate common ancestry from an actual cell — contra Dawkins, and most biology textbooks.
- Now, according to recent experiments made by Mr.H. Nagaoka on the elastic constants of rocks, [88] the mean velocity of seven archaean rocks is 5.1 kms. per sec. for the longitudinal waves, and 2.8 kms. per sec. for the transversal waves -- values which agree so closely with those obtained for the first two series of earthquake-waves as to leave little doubt with regard to their character.
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