氦氩同位素对蓝宝石成因的指示Genesis of Sapphires Indicated by Helium and Argon Isotopes
郭伟,赵倩怡,贺怀宇
摘要(Abstract)：
本文报道了斯里兰卡蓝宝石的氦、氩含量及同位素组成。采用真空压碎法获得蓝宝石流体包裹体中的氦、氩含量分别为3.7～4.9×10~(-6) cm~3STP/g和1.6～1.9×10~(-6) cm~3 STP/g,同位素组成分别为~3He/~4He=0.17～0.21 Ra和~(40)Ar/~(36)Ar=4348.7～4457.3。该特征与含刚玉的古老变质岩类似,接近纯地壳组分端元,指示其形成于壳内的变质作用过程。与山东省昌乐碱性玄武岩内岩浆成因的蓝宝石对比,发现二者具有显著不同的稀有气体同位素特征,其中昌乐蓝宝石含有强烈的幔源流体特征。提出稀有气体同位素及元素比值可有效判别蓝宝石的成因类型及形成过程。
关键词(KeyWords)： 蓝宝石;斯里兰卡;稀有气体;氦―氩同位素
基金项目(Foundation): 国家自然科学基金青年基金(41903011)资助
作者(Author): 郭伟,赵倩怡,贺怀宇
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