新疆拜城县波孜果尔A型花岗岩类为富含铌、钽、锆等有用元素的含矿岩体.通过偏光显微镜、电子探针(EpMA)化学成分分析、电子探针背散射(BSE)对波孜果尔A型花岗岩类的矿物学特征进行了研究,并对岩浆形成的温度条件与构造背景进行了讨论.结果表明,波孜果尔A型花岗岩类包括霓石钠闪石英碱性长石正长岩、霓石钠闪碱性长石花岗岩、黑云母碱性长石正长岩3种岩石类型.主要造岩矿物包括石英、钠长石、钾长石、霓石、钠铁闪石和铁叶云母.副矿物包括锆石、烧绿石、钍石、萤石、独居石、氟碳铈镧矿、磷钇矿等.岩浆平均温度832～839℃,形成于非造山的板内构造环境,且具高温、无水、低氧逸度的成岩特点.%The Boziguoer A-type granitoids in Baicheng County of Xinjiang are ore-bearing rocks with abundant useful elements such as Nb, Ta and Zr. The petrological and mineralogical characteristics of the A-type granitoids were investigated on the basis of observation under polarized microscope, chemical analysis and detailed BSE images using EPMA, followed by the discussion on the p-T conditions of A-type magma generation and the tectonic setting. The results indicate that these A-type granitoids could be divided into three types, namely ae-girine arfvedsonite quartz alkali feldspar syenite, aegirine arfvedsonite alkali feldspar granite and biotite alkali feldspar syenite. The major rock-forming minerals are quartz, albite, K-feldspar, aegirine, arfvedsonite and siderophyllite, whereas the accessory minerals include mainly zircon, pyrochlore, thorite, fluorite, monazite, bastnaesite and xenotime. The average temperatures of the magma are 832 ～ 839℃ . A-type granitoids might have been formed in an anorogenic intraplate tectonic setting by which they generally show such features as high- temperature, anhydrous nature and low fugacity.
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