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利用离子探针技术测定了一组安徽女山新生代玄武岩中单斜辉石巨晶的硼同位素组成.硼同位素比值非常不均一:δ~(11)B为+7.4％0～-28.6‰,既表现在不同样品之间,也表现在同一样品的内部.巨晶的硼同位素组成既没有记录暴露地表后的后期蚀变影响,也没有记录被携带上升过程中与寄主玄武岩浆和/或围岩的相互更应.不均一性继承自巨晶的地幔源区,其源区曾经经历过流体的交代作用.交代流体来自于初始硼同位素不均一并且经历不同程度脱水(脱硼)的海洋板块.结合氧同位素和Sr-Nd同位素来看,对交代流体的主要贡献可能来自于蚀变洋壳而不是海洋沉积物.
The boron isotopic compositions of clinopyroxene megacrysts in the Nüsan Cenozoic basalts of Anhui Province were determined by ion probe technique. The boron isotopic ratios are very heterogeneous: δ ~ (11) B is + 7.4% 0 ~ -28.6 ‰, The intergranular composition of the megacrysts neither records the post-alteration alteration after exposure to the earth’s surface, nor does it record any changes in the as-built basaltic magma and / or the surrounding rock The heterogeneity is inherited from the mantle source region of the giant crystal, whose source regions have undergone fluid metasomatism from the marine plate where the initial boron isotopes are heterogeneous and undergo different degrees of dehydration (deboronation). Oxygen isotopes and Sr-Nd isotopes, the major contribution to the replacement fluid may come from altered oceanic crust rather than marine sediments.