The ~(176)Hf/~(177)Hf and143Nd/144Nd of mid-ocean ridge basalts(MORB)and ocean island basalts(OIB)are significantly correlated and form the so-called Hf-Nd mantle array[1,2](Fig.1a).Model calculations show that the association of OIB with the array is inconsistent with the distinctive Hf and Nd isotopic compositions of their purported ancient sediment sources in the mantle[1].A current consensus for the origin of the array is that the Lu/Hf and The ~ (176) Hf / ~ (177) Hf and 143Nd / 144Nd of mid-ocean ridge basalts (MORB) and ocean island basalts (OIB) are highly correlated and form the so-called Hf-Nd mantle arrays [1,2] (Fig. 1a). Model calculations show that the association of OIB with the array is inconsistent with the distinctive Hf and Nd isotopic compositions of their purported ancient sediment sources in the mantle [1]. A current consensus for the origin of the array is that the Lu / Hf and