Table S8: Peridotite-melt distribution coefficients [C(Perid.)]/[C(melt)]) for melting ultra-depleted peridotite. Element D Cs 0.00054 Rb 0.000077 Ba 0.00027 Th 0.00037 U 0.00018 Nb 0.0026 K 0.00021 La 0.0011 Ce 0.0019 Pb 0.008 Pr 0.0027 Nd 0.0034 Zr 0.0076 Sr 0.0044 Sm 0.0061 Eu 0.0068 Gd 0.01 Tb 0.01 Dy 0.01 Ti 0.012 Y 0.018 Er 0.02 Yb 0.086 Cu 0.04 Sn 0.12 Mineral/melt D's from Eiler et al., 2005 Assumes 78.7 % Olivine, 18.8 % Orthopyroxene, 2 % Clinopyroxene and 0.5 % Spinel