The age of Earth is estimated to be 4.54 ± 0.05 billion years (4.54 × 109 years ± 1%).[1][2][3][4] This age may represent the age of Earth's accretion, or core formation, or of the material from which Earth formed.[2] This dating is based on evidence from radiometric age-dating of meteorite[5] material and is consistent with the radiometric ages of the oldest-known terrestrial material[6] and lunar samples.[7]
It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites. Because the time this accretion process took is not yet known, and predictions from different accretion models range from a few million up to about 100 million years, the difference between the age of Earth and of the oldest rocks is difficult to determine. It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages.
^"Age of the Earth". U.S. Geological Survey. 1997. Archived from the original on 23 December 2005. Retrieved 2006-01-10.
^ abWilde, S. A.; Valley, J. W.; Peck, W. H.; Graham C. M. (2001-01-11). "Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago". Nature. 409 (6817): 175–178. Bibcode:2001Natur.409..175W. doi:10.1038/35051550. PMID11196637. S2CID4319774.
^Valley, John W.; Peck, William H.; Kin, Elizabeth M. (1999). "Zircons Are Forever"(PDF). The Outcrop, Geology Alumni Newsletter. University of Wisconsin-Madison. pp. 34–35. Archived(PDF) from the original on 2009-02-26. Retrieved 2008-12-22.
^Wyche, S.; Nelson, D. R.; Riganti, A. (2004). "4350–3130 Ma detrital zircons in the Southern Cross Granite–Greenstone Terrane, Western Australia: implications for the early evolution of the Yilgarn Craton". Australian Journal of Earth Sciences. 51 (1): 31–45. Bibcode:2004AuJES..51...31W. doi:10.1046/j.1400-0952.2003.01042.x.