doi: 10.7185/geochemlet.1728 Using Melt-PX to model the decompression melting of a heterogeneous mantle, I investigated the role of major-element composition of the lithologies present in the source on magmatic productivity, and trace element and isotopic melt compo-sitions, independently of the bulk mantle composition. My calculations demon-strate that the volume of magma produced is not significantly affected by the nature of the lithological heterogeneity, but depends on the bulk mantle compo-sition. However, an isochemical bulk mantle can produce contrasting trace element and isotopic melt compositions depending on the major-element compositions of the lithologies present in the source. Results show that the observed crust thick-ness of the Icelandic rift zones is consistent with about 10 % of recycled crust in the source, but also demonstrate there is no need to involve the contribution of melts derived from a recycled basalt compo-nent to explain the compositional variability of the Icelandic basalts in rift zones, and rather advance the contribution of olivine-bearing hybrid lithologies formed by solid-state reactions between the recycled crust and the peridotite.
Lambart, S. (2017). No direct contribution of recycled crust in Icelandic basalts. Geochemical Perspectives Letters, 7–12. https://doi.org/10.7185/geochemlet.1728