尖晶石－石榴石相转变过程中矿物的微量元素组成与分布特征

Trace elements composition and distribution characteristics in minerals in the process of phase transformation from spinel to garnet

利用质子微探针和微束ＰＩＸＥ定量分析技术对山东梭罗树地慢橄榄岩中橄榄石、斜方辉石、单斜辉石、尖晶石和石榴石等矿物的微量元素组成与分布进行了研究。结果表明，不相容元素（Ｓｒ、Ｙ、Ｚｒ）主要富集于单斜辉石内，尖晶石则几乎富集质子探针所能检出的所有微量元素，而石榴石中微量元素含量最少。该研究表明，在矿物微区微量元素分布是十分不均匀的，推测可能受地幔交代过程中溶液的渗滤效应以及存在微粒包裹体的共同制约。

The proton microprobe and micro-PIXE quantitative analysis technique have been used to determine the tyace elements composition and distribution in minerals such as olivine, orthopyroxene, clinopyroxene, spinel and garnet from Suoluoshu mantle peridotite from Shandong Province. The results show that clinopyroxene mainly concentrates incompatible elements (Sr, Y and Zr) while spinel concentrates almost all of the trace elements the proton microprobe can detect; and garnet concentrates very little trace elements. The study indicates that distribution of the trace elements in micron area of minerals is very heterogeneous. It is supposed that the heterogeneity results from the combined restraints of the solution infiltration effect and the existence of micrograined inclusions in the process of mantle metasomatism.