白杨河超大型铍(铀)矿床中蓝柱石(BeAlSiO4(OH))的矿物特征与地质意义

蓝柱石作为一种较为罕见的含铍矿物,通常产在过铝-准铝性的岩浆-热液演化系统中,或发育于富铝质岩石的低级变质过程中。本文通过偏光显微镜、电子探针、X射线粉晶衍射、激光拉曼光谱和红外光谱等多种手段方法,在白杨河超大型铍(铀)矿床首次发现了除羟硅铍石以外的另一种含铍矿物-蓝柱石。系统的矿物学研究表明蓝柱石应由花岗斑岩岩浆分异的岩浆热液直接沉淀而成,且形成于富F环境中。结合前人关于矿床地质特征、成矿年代学和地球化学等方面的研究,认为白杨河矿床中的铍矿化应是花岗斑岩深部岩浆房分异的岩浆热液,在不断演化过程中形成的,而与后期流体(包括幔源流体和大气降水)的淋滤作用无关或关系很小。

The mineralogical characteristics of euclase(BeAlSiO4(OH))in the Baiyanghe super-large beryllium(uranium)deposit and their geological significances

As a rare Be-bearing mineral,euclase commonly occurred in the peraluminous-metaluminous magmatichydrothermal system,or in the low-grade Al-rich metamorphic rocks.In this study,by using various methods of polarizing microscope,electron probe microanalyzer,X-ray powder diffraction,laser Raman spectroscopy,and infrared spectroscopy,euclase has been identified for the first time in the Baiyanghe super-large beryllium(uranium)deposit besides the main Be-bearing mineral of bertrandite.The systematic mineralogical studies show that euclase in the Baiyanghe deposit should be deposited directly from the magmatic fluid,which was derived from the magma of granite porphyry,in the fluorine-rich environment.According to previous researches on geological characteristics,metallogenic geochronology,and geochemistry of the deposit,it is suggested that the Be mineralization in the Baiyanghe deposit may be mainly occurred in the continuous evolution process of magmatic fluid which was derived from the magma of granite porphyry,with little or no relationship to the leaching process of later fluids(including mantle-derived fluid or meteoric water).