Growth of continental crust and lithosphere subduction in the Hadean revealed by geochemistry and geodynamics
Adrien Vezinet, А В Чугунов, А. В. Соболев, Charitra Jain, S. V. Sobolev, Valentina Batanova, Evgeny Asafov, A. N. Koshlyakova, Nicholas Arndt, Leonid V. Danyushevsky, John W. Valley
Abstract
Sr = 0.69932 ± 0.00024, 95% confidence interval) of melts included in olivine from 3.27 Ga komatiitic lava flows in the Barberton Greenstone Belt, South Africa. This component indicates a model age of 4.31 ± 0.19 Ga and significant chemical fractionation (Nb/U = 36.9 ± 1.5, Ce/Pb=16.7 ± 1.1), suggesting up to 80% ± 16% of the present-day continental crust's mass was extracted by the late Hadean from the whole mantle. Geodynamic models support this finding, explaining geochemical data by producing 40% to 70% of the present-day continental crust mass during the Hadean in a variable tectonic regime with tens of millions of years-long periods of massive impulsive subduction induced by mantle plumes.