Trace-element of Tuoyun cli-nopyroxene:Implication for the deep processes of litho-spheric mantle beneath the southwest Tianshan,West China  

作　　者：ZHENG Jianping LU Fengxiang S.Y.O’Reilly LUO Zhaohua 

机构地区：[1]Faculty of Earth Sciences,China University of Geosciences,Wuhan 430074,China [2]Department of Earth and Planetary Sciences,Macquarie University,Sydney,NSW2109,Australia [3]Faculty of Earth Sciences,China University of Geosciences,Beijing 100083,China

出　　处：《Chinese Science Bulletin》2001年第14期1206-1211,共6页

基　　金：This work was supported by the National Natural Science Foundation of China (Grant Nos. 40072021 and 49733110) ;and the State Key Basic Research Development Program (Grant No. G1999043303).

摘　　要：Based on the LAM-ICPMS analytic results on the trace elements of clinopyroxenes in peridotitic xenoliths occurring in early-Cretaceous basalts from western Xinjiang, the properties and the deep processes, including partial melting and mantle metasomatism, of the subcontinental lithospheric mantle beneath the Tuoyun Basin are analyzed. In the northern edge of the Tarim Basin (southwest Tian-shan), the Mesozoic subcontinental lithosphere which has experienced the effect of partial melting (【10%) and intricate mantle metasomatism is characterized by Phanerozoic ’ocean-type’ mantle. The superposed influence of SiO2-un-saturated silicate melt and carbonate melt probably results in the metasomatic medium which resembles the hydrous silicated carbonate melt in some aspects. By comparing Tuoyun mantle with Cenozoic main mantle beneath eastern China, the properties are similar, while the former shows finer grain and higher diopside content of the peridotites and more conspicuous modal metasomatism.Based on the LAM-ICPMS analytic results on the trace elements of clinopyroxenes in peridotitic xenoliths occurring in early-Cretaceous basalts from western Xinjiang, the properties and the deep processes, including partial melting and mantle metasomatism, of the subcontinental lithospheric mantle beneath the Tuoyun Basin are analyzed. In the northern edge of the Tarim Basin (southwest Tianshan), the Mesozoic subcontinental lithosphere which has experienced the effect of partial melting (<10%) and intricate mantle metasomatism is characterized by Phanerozoic ‘ocean-type’ mantle. The superposed influence of SiO2-unsaturated silicate melt and carbonate melt probably results in the metasomatic medium which resembles the hydrous silicated carbonate melt in some aspects. By comparing Tuoyun mantle with Cenozoic main mantle beneath eastern China, the properties are similar, while the former shows finer grain and higher diopside content of the peridotites and more conspicuous modal metasomatism.

关 键 词：WEST China MANTLE CLINOPYROXENE LAM-ICPMS MANTLE heterogeneity deep process. 

分 类 号：P59[天文地球—地球化学]