Dating of pre-solar material using La-Ce and Sm-Nd decay systems

1)在阿连德陨石中发现了6个具有Ce异常的CAI包裹体，用中子活化分析方法对90个来自阿连德陨石的CAI包裹体进行了稀土元素分析。根据其稀土元素丰度模式，将CAI分为三组。（2）Ce-Nd-Sr同位素质谱分析技术的进步，使微量放射性同位素的分析结果更加准确，重复分析的结果为：δ <138>Ce/δ <142>Ce和δ <136>Ce/δ <142>Ce分别为0.0225889±0.0000013和0.0168810± 0.000030;（3）单矿物颗粒Rb/Sr等时线测年技术的发展，该方法使我们能够根据矿物颗粒内部Rb/Sr的不均匀性来绘制等时线。（4）~（16）La-~（16）Ce、~（16）Sm-~（16）Nd、~（16）Rb-~（16）<138><138><147><143><87><87>Sr同位素体系在地球化学和宇宙化学研究中的应用。硅质岩中的铈异常被认为是大气含氧的证据。新资料表明Ce异常的形成年龄为1.1Ga。5）Sm同位素双尖峰测量技术的发展与应用我们的技术实现了Sm-Sm双尖峰测量Sm同位素变化的精度为0.03‰/amu（1 SD）<150><154>。

1)The finding of six CAI inclusions with Ce anomaly from Allende meteorite.Ninety CAI inclusions from Allende meteorite were analyzed for REE by INAA method. The CAI was classified into three groups by their REE abundance pattern. Six inclusions among them were found to have negative Ce anomaly.2)The advancement of the mass spectrometry for trace amount of Ce-Nd-Sr radiogenic isotopes acc urately.The analytical results for repeated analyses are 0.0225889±0.0000013 and 0.0168810±0.0000030 for ^<138>Ce/^<142>Ce and ^<136>Ce/^<142>Ce, respectively.3)The development of Rb-Sr isochron dating technique using the single mineral grain.This method enables us to draw an isochron by Rb/Sr heterogeneity reside inside the mineral grain. A K-feldspar of a dyke from Gifu Prefecture shows magmatic event and a chlorite in the same rock shows an alteration date.4)Many applications of ^<138>La-^<138>Ce,^<147>Sm-^<143>Nd,^<87>Rb-^<87>Sr isotope systematics to various geochemistry and cosmochemistry.Ce and Nd isotopes and REE pattern of Barberton sedimentary rocks were examined. Ce anomaly found in the chert was regarded as a proof of air oxygen in atmosphere. The new data indicate that the Ce anomaly was formed at 1.1Ga.5)The development of Sm isotopes measurement technique using double spikes and its application Our technique achieved to measure Sm isotope variations with accuracy of 0.03‰/amu(1SD) using ^<150>Sm-^<154>Sm double spikes.