摘要
There are a large number of Mesozoic intrusive and volcanic rocks in western Liaoning of China,which is an ideal place to study the Mesozoic Paleo-Pacific subduction processes,and lithospheric destruc-tion of North China Craton.Detailed petrographic,zircon U-Pb dating and geochemical studies of the Early Jurassic granites in Huashan pluton,Xingcheng,western Liaoning,indicate that the Early Jurassic granites were formed at 184-174 Ma,mainly composed of syenite and monzogranite.The geochemical characteristics show high contents of SiO_(2),Al_(2)O_(3)and Na_(2)O+K_(2)O,low contents of Fe_(2)O_(3)and MgO,enrichment in LREEs and LILEs,and depletion in HREEs and HFSEs,and have a high content of Sr and low contents of Y and Yb,with weak negative Eu anomalies and slightly negative anomalies of Ce,indicating that they are a set of intermediate-acidic adakitic granites in high-K calc-alkaline series.All the facts significantly suggest that the Early Jurassic adakitic granites were formed at the active continental margin in the context of Paleo-Pacific plate subduction.
基金
Supported by the National Key R&D Program of China(No.2016YFC0666108-02).
