Chondrite barium, neodymium, and samarium isotopic heterogeneity and early earth differentiation

Isotopic variability in barium, neodymium, and samarium in carbonaceous chondrites reflects the distinct stellar nucleosynthetic contributions to the early solar system. We used Nd-148/Nd-144 to correct for the observed s-process deficiency, which produced a chondrite Sm-146-Nd-142 isochron consistent with previous estimates of the initial solar system abundance of Sm-146 and a Nd-142/Nd-144 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 Nd-142 in chondrites relative to terrestrial rocks reflects Sm-146 decay and early planetary differentiation processes.