Carlson Richard W, Boyet Maud, Horan Mary
Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, USA.
Science. 2007 May 25;316(5828):1175-8. doi: 10.1126/science.1140189.
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.
碳质球粒陨石中钡、钕和钐的同位素变化反映了不同恒星核合成对早期太阳系的贡献。我们使用148Nd/144Nd来校正观测到的s过程亏损，这产生了一个球粒陨石146Sm-142Nd等时线，与先前对太阳系初始146Sm丰度的估计一致，并且在平均球粒陨石Sm/Nd比下的142Nd/144Nd低于在地球岩石中测量值21±3 ppm。这一结果强化了以下结论：球粒陨石中相对于地球岩石的142Nd亏损反映了146Sm衰变和早期行星分化过程。
