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单词 Hadean
释义
Hadean

Biology
  • The earliest eon in the history of the earth, from the time of the accretion of planetary material, around 4600 million years ago (mya), to the date of the oldest known rocks—and hence the beginning of the geological record—about 4000 mya. The young earth was probably a rocky planet with a hot interior and a moist surface with oceans of liquid water. No evidence of life has been found. The Hadean eon precedes the Archaean eon.


Geology and Earth Sciences
  • An informal name for the eon of Earth history from the formation of the Earth 4567.17 Ma ago until the undefined start of the Archaean 3800 Ma ago (Int. Commission on Stratigraphy, 2004).


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