Petrogenesis of alkaline rocks in Datuanliujia Be deposit,Jiaodong Peninsula,and its constraint on mineralization:Evidence from zircon U-Pb geochronology,geochemistry and Sr-Nd-Hf isotopes
The Datuanliujia is a Be deposit,which is hosted in the medium-fine grain syenite on the southeastern margin of the North China Block.The deposit is controlled by NW fault and contains 7 orebodies with lenticular shapes.The ore mineral is bertrandite,which is associated with sericite,calcite,barite and limonite.The deposit has obvious metallogenic specialization,and Be,Mo,Rb,Cs,REE elements have a good positive correlation,but a negative correlation with CaO.The syenogranite have high SiO2,and alkalis,but low magnesium and iron,belong to metaluminous-weakly peraluminous series.The syenite have high alkalis,but low SiO2,belong to metaluminous series.All rocks are obvious light and heavy rare earth fractionation,light rare earth enriched,and no obvious negative Eu anomaly.Trace elements show LILEs enriched,negative Nb,Ta,and Ti anomalies,depleted in HFSEs,and possess of the same partition pattern for rare earth and trace elements.Zircon LA-ICP-MS U-Pb dating gives the emplacement age of 200.3±1.3Ma for syenogranite.The εNd(t)values varying from-15.8 to-15.4 for the syenogranite,but in-situ analyses of zircons show that the syenogranites have heterogeneous Hf isotopic compositions and εHf(t)varying from-25.5 to-7.5.Zircon LA-ICP-MS U-Pb dating gives the emplacement age of 200.9±1.4Ma for syenite.The in-situ analyses of zircons show that the syeniteεHf(t)varying from-23.2 to-15.7.The geochemical studies indicated that syenite are derived from partial melting of the enriched lithospheric mantle of North China Block which undergone continental crust metasomatism in South China Block,syenogranite are derived from subducted continental crust of South China Block.Both of them are formed in the stage of exhumation.
GeochemistryOre geologyLA-ICP-MS U-Pb zircon datingSr-Nd-Hf isotopesDatuanliujia Be depositJiaodong Peninsula
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维普
