地幔岩流体包裹体的稀土元素初步研究

REE in Mantle Xenolith and Mantle Fluids

地幔流体REE的研究有助于了解地幔区域化学不均一性、地幔的富集与亏损等地幔地球化学特征。当前对地幔流体的REE研究,主要是通过对比富CO2包裹体与贫CO2包裹体的地幔岩或地幔矿物的测试分析来间接获得信息。本文尝试运用电感耦合等离子体质谱(ICP MS)和热爆方法,直接测定了长白山地区的地幔捕虏体中流体 熔体包裹体REE含量。初步研究显示流体 熔体包裹体中富含REE,尤其LREE相对富集;REE组成曲线右倾,Eu弱正异常,与地幔岩的寄主玄武岩REE组成特征相似,反映源区地幔岩的交代特征。

Study on REE in mantle fluids has significance for understanding of regional geochemical difference, mantle enrichment and depletion. Recently, REE study on mantle fluids is indirectly achieved through the comparison of CO2rich and CO2poor fluid inclusions in mantle minerals. REE in fluidmelt inclusions of mantle xenolith from Changbaishan are measured directly by ICPMS. The primary study shows that fluidmelt inclusions enrich REE, particularly with higher LREE. The REE distribution pattern curve is decline to the right with a slight positive Eu anomaly and is similar to that of the mantle xenolith host basalt. It indicates that the source of mantle xenolith may be experienced a metasomatic process.