东昆仑格尔木东部金水口片麻状富铝花岗岩锆石微区Raman光谱研究

    Raman spectroscopic study of zircons in the Jinshuikou gneissic Al-rich granite in east Golmud, East Kunlun.

    • 摘要: 通过对金水口片麻状富铝花岗岩中锆石的宏观形态特征和微区Raman光谱特征的研究发现,该套片麻状花岗岩中的锆石主要有2种类型:颗粒较小的简单锆石和颗粒较大的复杂锆石。复杂锆石由3部分组成:细小的残留核、浅色部分和褐色部分。简单锆石和复杂锆石核部残留锆石均为变质成因;复杂锆石的浅色部分和褐色部分均为岩浆锆石。结合锆石Raman谱线研究结果,对金水口片麻状富铝花岗岩已有的锆石U-Pb年龄进行进一步的解释,认为390-414Ma可能代表了复杂锆石的浅色部分或褐色部分的岩浆锆石的形成时代,而1600-1800MaW能记录了复杂锆石核部变质事件的时代。

       

      Abstract: Studies of the macroscopic morphology of zircons in the Jinshuikou gneissic Al-rich granite and the characteristics of the micro-area Raman spectra show that zircons in this gneissic granite mainly have two types: relatively small, simple zircon and relatively big, complex zircon. Complex zircon consists of three parts: a smaller relict core, a light-colored part and a brown part. Simple zircon and the smaller relict core in complex zircon are both of metamorphic origin. The light-colored and brown parts in complex zircon are both magmatic zircon. On that basis, combined with a study of the zircon Raman spectra, a reinterpretation of the available zircon U-Pb age of the Jinshuikou gneissic Al-rich granite has been made. The authors think that 390-414 Ma might represent the formation age of the magmatic zircon of the light-colored part or the brown part in complex zircon, while 1600-1800 Ma might represent the age of the metamorphic event in the relict core in complex zircon.

       

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