The Amount of Recycled Crust in Sources of Mantle-Derived Melts

A. V. Sobolev (1, 2) , A. W. Hofmann (1) , D. V. Kuzmin (1, 3) , G. M. Yaxley (4) , Nicholas Arndt (5) , Et Al.

1 MPIC - Max Planck Institute for Chemistry
2 GEOKHI - Vernadsky Institute of Geochemistry and Analytical Chemistry
3 Sobolev Institute of Geology and Mineralogy [Novosibirsk]
4 RSES - Research School of Earth Sciences [Canberra]
5 LGCA - Laboratoire de Géodynamique des Chaines Alpines

Plate tectonic processes introduce basaltic crust (as eclogite) into the peridotitic mantle. The proportions of these two sources in mantle melts are poorly understood. Silica-rich melts formed from eclogite react with peridotite, converting it to olivine-free pyroxenite. Partial melts of this hybrid pyroxenite are higher in nickel and silicon but poorer in manganese, calcium, and magnesium than melts of peridotite. Olivine phenocrysts' compositions record these differences and were used to quantify the contributions of pyroxenite-derived melts in mid-ocean ridge basalts (10 to 30%), ocean island and continental basalts (many >60%), and komatiites (20 to 30%). These results imply involvement of 2 to 20% (up to 28%) of recycled crust in mantle melting.

A. V. Sobolev, A. W. Hofmann, D. V. Kuzmin, G. M. Yaxley, Nicholas Arndt, et al.. The Amount of Recycled Crust in Sources of Mantle-Derived Melts. Science, 2007, 316 (5823), pp.412 à 417. ⟨10.1126/science.1138113⟩. ⟨insu-00351049⟩