Re-Os同位素体系在陨石研究中的应用  

APPLICATIONS OF THE Re-Os ISOTOPE SYSTEM TO METEORITES

作　　者：杨刚[1] 谢智[1] 陈江峰[1] 

机构地区：[1]中国科学技术大学地球与空间科学系化学地球动力学研究实验室,安徽合肥230026

出　　处：《地学前缘》2001年第2期339-344,共6页Earth Science Frontiers

基　　金：高等学校博士学科点专项科研基金! (96 0 35 815 )资助

摘　　要：铁陨石中的Re ,Os含量反映其结晶分异历史。通过铁陨石定年修正187Re的衰变常数为 :λ(187Re) =1 6 6 6× 10 -11a-1。ReOs同位素测年法可以直接用于对铁陨石的定年 ,结果表明天然铁陨石大体同时形成 ,但ReOs定年技术已有可能揭示不同化学群铁陨石形成年代的序列 ,但研究尚需深入。这些方法也可以用来探讨铁陨石和石铁陨石的形成源区、冷却历史和后期变化。虽然在石陨石中Re ,Os同位素的浓度很低 ,但也有了探索性研究成果。随着技术的不断发展 ,ReOs同位素体系在天体化学中的作用将愈加明显和重要。The concentrations of Re and Os in iron meteorites could indicate the history of differentiation and crystallization of irons. The decay constant of 187 Re has been corrected by studying iron meteorites and the new decay constant λ ( 187 Re)=1 666×10 11 a 1 . Re Os chronology could be directly used to date iron meteorites. The results from the method show that all iron meteorites were formed at about the same time. However, further study suggests that different groups of irons were crystallized at slightly different times. This method also helps in studying the source, cooling history and secondary alterations of the chondrites and iron meteorites. Although the Re and Os concentrations are very low in the ordinary chondrites, some results have been obtained in this field. As a powerful cosmochemical tracer, the Re Os isotopic system will help much in a better understanding of origin and evolution of meteorites.

关 键 词：铁陨石 石陨石 结晶分异 冷却史 铼-锇法定年 形成年代 铼同位素 衰变常数 

分 类 号：P68[天文地球—地质学]