Evidence from coupled (Sm-147)-(Nd-143) and (Sm-146)-(Nd-142) systematics for very early (4.5-Gyr) differentiation of the earth's mantle

Evidence for early differentiation of the earth's mantle is presented based on measurements of Nd-143/Nd-144 and Nd-142/Nd-144 ratios in an approximately 3.8 Gyr-old supracrustal rock from Isua, West Greenland. Coupled (Sm-146,147)-(Nd-142,143) systematics suggest that the fractionation of Sm/Nd took place 4.44-4.54 Gyr ago, due to extraction of a light rare earth element-enriched primordial crust.