Overview of Nd Isotopic Variations

Abstract

The chondritic meteorites probably provide the best samples of the building blocks from which the terrestrial planets were constructed (e.g. Ringwood 1975). They are primitive objects composed of condensates from the solar nebula that have suffered little further modification. As discussed in Chaps. 1 and 3, the inference that Sm and Nd condensed from the solar nebula at a high temperature implies that their relative proportions in chondritic meteorites, and indeed in all of the planets, should be the same as in the solar nebula (i.e., the sun). Because the chondrites have not been affected by magmatic processes, they provide an estimate of the bulk-earth values of Sm/Nd and ¹⁴³Nd/¹⁴⁴Nd.