六个中国普通球粒陨石的组成和各相元素分布

THE COMPOSITIONS AND ELEMENT DISTRIBUTIONS OF DIFFERENT PHASES IN SIX CHINESE ORDINARY CHONDRITES

本文运用INAA测定了6个中国普通球粒陨石磁性相21个元素和非磁相20个元素的含量。5个H群球粒陨石的组成没有显示出明显的差异,但其元素丰度明显地不同于另一个L群的肇东球粒陨石。相对于CI,磁性相中Ga归一化的元素丰度可以作为普通球粒陨石分群的指示剂。根据普通球粒陨石各相元素丰度建立的模式成分和组成与全岩分析结果一致。

Six Chinese ordinary chondrites (four of them were fallen in recent years and trace element abundances have not been reported for the other two) were examined. The contents of21 elements (Na,Cr,Mn,Sc,Se,Zn,Br,Ni,Fe,Co,Ir,Cu,Ga,As,Au, Sb,Os,W,Re, Pt, and Ru) in the magnetic fractions and 20 elements (Na,K,Ca,Sc,Cr, Mn, Fe, Co, Ni,Zn, Se, Br, La,Sm,Eu, Yb, Lu, Ir, Au, and As) in the non-magnetic fractions were determined by INAA.The results indicate that the 5 H-group chondrites show almost no difference in composition, but their element abundances are different from those of the Zhaodong L-gfoup chondrite. As a normal element (relative to CI), the concentration of Ga in the magnetic fraction can be used to classify ordinary chondrites (H-, L- and LL-group). The bulk composition of different phases and the modal weight of each component calculated from element concentrations in them are in good agreement with recommended bulk analyses.