Chondrite Barium, Neodymium, and Samarium Isotopic Heterogeneity and Early Earth Differentiation

Abstract

Isotopic variability in barium, neodymium, and samarium in carbonaceous chondrites reflects the distinct stellar nucleosynthetic contributions to the early solar system. We used ¹⁴⁸Nd/¹⁴⁴Nd to correct for the observed s-process deficiency, which produced a chondrite ¹⁴⁶Sm-¹⁴²Nd isochron consistent with previous estimates of the initial solar system abundance of ¹⁴⁶Sm and a ¹⁴²Nd/¹⁴⁴Nd at average chondrite Sm/Nd ratio that is lower than that measured in terrestrial rocks by 21 ± 3 parts per million. This result strengthens the conclusion that the deficiency in ¹⁴²Nd in chondrites relative to terrestrial rocks reflects ¹⁴⁶Sm decayand earlyplanetary differentiation processes.