电子探针在新疆拜城碱性花岗岩烧绿石研究中的应用

Application of EPMA to pyrochlore study from Baicheng alkali granite,Xinjiang

本文利用电子探针对新疆拜城碱性花岗岩中的烧绿石进行了研究。通过背散射图像分析可知拜城碱性花岗岩中烧绿石多为不规则粒状,颗粒直径在30～150μm,与氟碳铈镧矿、萤石、磁铁矿等伴生;利用元素面扫描得出碱性花岗岩烧绿石中Nb、Ta、U、La、Ce、F等稀有、稀土元素的分布情况;并对碱性花岗岩中烧绿石进行了定量分析,表明本区产出的烧绿石Na、Ca等元素主要被U、REE、Th等元素替代,烧绿石中SiO2和U3O8含量呈正相关;在黑云钠闪石英二长岩中产出的烧绿石CaO,TiO2,ZrO2,U3O8的含量相对多,而在霓石钠闪石英二长闪长岩中产出烧绿石Ce2O3的含量相对多。

The study on pyrochlores in Baicheng alkali granite is carried out by means of the Electron Probe Micro Analysis（EPMA）.Back scatter electron（BSE） image analysis shows that the pyrochlores in Baicheng granites are mostly irregular granular,and the mineral particle diameter is 30~150 μm,which are associated with bastnaesite,fluorite,magnetite etc.The distribution of Nb Ta U La Ce F in alkali granite is studied by means of elements scanning microanalysis.A quantitative analysis on pyrochlores in Baicheng alkali granite is studied too.Results show that Na,Ca etc.are mainly replaced by U,REE,Th etc.SiO2 and U3O8 are positively correlated in pyrochlores.In quartz monzonite containing biotite and riebeckite,the contents of CaO,TiO2,ZrO2,U3O8 in pyrochlore are high.In Quartz-diorites containing aegirine and riebeckite,the contents of Ce2O3 in pyrochlore are high.