Earth’s composition was modified by collisional erosion

Science 377, 1527-1532 Link to Article [DOI: 10.1126/science.abq735]
1Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France.
2Institute of Geochemistry and Petrology, ETH Zürich, Zürich, Switzerland.
3Bayerisches Geoinstitut, Universität Bayreuth, 95447 Bayreuth, Germany.
4Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada.
Reprinted with permission from AAAS

The samarium-146 (146Sm)–neodymium-142 (142Nd) short-lived decay system (half-life of 103 million years) is a powerful tracer of the early mantle-crust evolution of planetary bodies. However, an increased 142Nd/144Nd in modern terrestrial rocks relative to chondrite meteorites has been proposed to be caused by nucleosynthetic anomalies, obscuring early Earth’s differentiation history. We use stepwise dissolution of primitive chondrites to quantify nucleosynthetic contributions on the composition of chondrites. After correction for nucleosynthetic anomalies, Earth and the silicate parts of differentiated planetesimals contain resolved excesses of 142Nd relative to chondrites. We conclude that only collisional erosion of primordial crusts can explain such compositions. This process associated with planetary accretion must have produced substantial loss of incompatible elements, including long-term heat-producing elements such as uranium, thorium, and potassium.


Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s