Compositional trends of Icelandic basalts: Implications for short-length scale lithological heterogeneity in mantle plumes

摘要: Lithological variations in the mantle source regions under mid-ocean ridges and ocean islands have been proposed to play a key role controlling melt generation basalt composition. Here we combine compositional observations from Icelandic basalts modelling of melting bi-lithologic peridotite-pyroxenite demonstrate that, while short-lengthscale major element variation is present Iceland, heterogeneity does not make an important contribution excess production. By identifying characteristics endmember melts, find enriched melts be characterised by low SiO2 CaO, but high FeO. We quantitatively compare compositions experimental partial generated range lithologies, pressures fractions. This comparison indicates that single composition cannot account for all variation; depleted can produced peridotite melting, best matched sources refertilised addition up 40% ridge basalt. The beneath Iceland more fusible than as such will over-represented accumulated compared with its abundance source. Modelling combined our observational constraints on mantle, crustal thickness North Atlantic must primarily due temperature flow field variations.