锆石阴极发光和U-Pb年龄特征研究

根据锆石阴极发光和微区U-Pb定年的年龄结果,表明皖南新元古代花岗闪长岩中包含三类不同成因的锆石,即:同岩浆锆石、简单结构继承锆石和继承锆石核。同岩浆锆石能够反映岩体的形成时代与侵位条件,继承锆石反映岩浆岩的物质源区和岩浆形成条件。通过各岩体锆石样品的不同成因锆石分析研究,得出皖南新元古代各花岗闪长岩体具有相似的形成过程,但来自于不同的岩浆房,岩浆形成深度和侵位条件不同,与其形成于弧陆碰撞带的构造环境是一致的。

Study on Zircon CL and U-Pb Age of Neoproterozoic Granodiorites in South Anhui

On the basis of cathodoluminescence images and U-Pb dating,the analysed zircons embodied in Neoproterozoic granodiorites in South Anhui can be divided into three groups: synmagmatic zircon,simple-structured inherited zircon and inherited zircon core.The formation age and emplaced tectonic setting of plutons can be acquired from Synmagmatic zircon,the information about its protolith and magma formation can be inferred from inherited zircon.On the basis of studies of different kinds of zircon in the plutons,it is inferred that the three plutons of granodiorite in South Anhui derive from similar source rocks,but from different magma chambers,which were produced at different depths of crust and also emplaced into different depths of crust,coincident with the tectonic setting of arc-continent collision.