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142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth
M. Boyet* and
R. W. Carlson
New high-precision samarium-neodymium isotopic data for chondriticmeteorites show that their 142Nd/144Nd ratio is 20 parts permillion lower than that of most terrestrial rocks. This differenceindicates that most (70 to 95%) of Earth's mantle is compositionallysimilar to the incompatible elementdepleted source ofmid-ocean ridge basalts, possibly as a result of a global differentiation4.53 billion years ago (Ga), within 30 million years of Earth'sformation. The complementary enriched reservoir has never beensampled and is probably located at the base of the mantle. Thesedata influence models of Earth's compositional structure andrequire revision of the timing of global differentiation onEarth's Moon and Mars.
Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W., Washington, DC 20015, USA.
Published online 16 June 2005
Include this information when citing this paper.
* To whom correspondence should be addressed. E-mail: boyet{at}dtm.ciw.edu
B. Bourdon, M. Touboul, G. Caro, and T. Kleine (2008)
Phil Trans R Soc A
366, 4105-4128
|Abstract »|Full Text »|PDF »
Isotopes as clues to the origin and earliest differentiation history of the Earth.
S. B Jacobsen, M. C Ranen, M. I Petaev, J. L Remo, R. J O'Connell, and D. D Sasselov (2008)
Phil Trans R Soc A
366, 4129-4162
|Abstract »|Full Text »|PDF »
Collisional erosion and the non-chondritic composition of the terrestrial planets.