Rare earth elements in CO₂-fluid inclusions in mantle Iherzolite

Jiuhua Xu, Yuling Xie, Lijun Wang , Heping Zhu, and Liquan Wang Department of Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; The Research Center of Mineral Resources Exploration, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China

摘 要：<正> Trace elements including REE （Rare Earth Elements） in fluid inclusions in Iherzolite, olivine, orthopyroxene, and clinopyroxene have been determined by heating-decrepitation and ICP-MS （Element Type Inductively Coupled Plasma-Mass Spectrometry） method. Normalized CO2 fluid/chondrite data show that mantle fluids are rich in REEs, especially LREEs （Light Rare Earth Elements）, several times or dozen times higher than mantle rocks and mantle minerals. There are close relationships among the REE data of olivine, orthopyroxene, clinopyroxene and 1herzolite. Compared to the data of chemical dissolution method, it is believed that REE data obtained from heating-decrepitation and ICP-MS technique are contributed by CO2 fluid inclusions. About 60% （mass fraction） of tiny inclusions are observed not to be decrepitated above 1000℃, so REE data obtained are only contributed by decrepitated inclusions. Mantle fluids rich in LREE play an important role in mantle metasomatism, partial melting and mineralization.

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