Extended Data Fig. 7: Covariation in Al over Mg depletion versus ytterbium depletion.
From: Deep, ultra-hot-melting residues as cradles of mantle diamond
Whole-rock data for n = 183 cratonic xenoliths from various cratons7,18,106 (colour-coded as per legend) show a positive correlation between depletion in Al (relative to Mg) and Yb concentration. Superimposed on the observed data is the trend modelled for the restite after isobaric 5-GPa incremental melt loss. This shows the decreasing fertility as the composition trends away from primitive-mantle-like solid composition as gradual consumption of garnet through the series of melting reactions (Fig. 2 inset) reduced Al and increased Mg (see Extended Data Table 1). The gradual consumption of garnet, clinopyroxene and orthopyroxene cause the concomitant decrease in Yb concentration in the restite. The incremental model follows the trend of cratonic xenolith data away from primitive mantle, unlike high-pressure trends suggested in other studies6.
