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

1)在Allende陨石中发现6个具有Ce异常的CAI包裹体。用INAA法对来自Allende陨石的90个CAI包裹体进行了稀土元素分析。根据稀土元素丰度模式，将其划分为3组。其中6个包裹体存在负Ce异常。2)质谱法准确测定痕量Ce-Nd-Sr放射性同位素的进展。对于^<138>Ce/^<142>Ce和^<136>Ce/^<142>Ce，重复分析结果分别为0.0225889±0.0000013和0.0168810±0.0000030。3)单矿物颗粒Rb-Sr等时线测年技术的发展。这种方法使我们能够根据矿物颗粒内Rb/Sr的非均质性绘制等时线。岐阜县某岩脉的钾长石显示岩浆事件，同一岩石中的绿泥石显示蚀变日期。4) ^<138>La-^<138>Ce,^<147>Sm-^<143>Nd,^<87>Rb-^<87>Sr同位素系统学在各种地球化学和宇宙化学中的应用。研究了巴伯顿沉积岩的Ce、Nd同位素和稀土模式。在燧石中发现的Ce异常被认为是大气中存在氧气的证据。新资料表明，Ce异常形成于1.1Ga。采用^<150>Sm-^<154>Sm双尖峰测量技术，实现了Sm同位素变化测量精度为0.03‰/amu（1SD）。

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.