ABSTRACT

When ¹⁹³Nd/¹⁴⁴Nd ratios of oceanic basalts are plotted against the observed Sm/Nd ratios, the points appear widely scattered. But when a reduction procedure is applied on the basis of a model for development of oceanic basalt REE patterns with D^Sm/D^Nd = 1.32, one can obtain a linear correlation between ¹⁴³Nd/¹⁴⁴Nd and ¹⁴⁷Sm/¹⁴⁴Nd, with two subparallel alignments. Ages (∼730 and 1600-1900Myr) deduced therefrom can be consistent with those presented for development of continental crust.