摘要
白云母是常见的造岩矿物之一,广泛分布于花岗岩、伟晶岩、云英岩和变质岩中,其形成过程受多种因素制约,具有重要的岩石学意义。选取江西大岭上钨矿区强过铝质花岗岩中的白云母为研究对象,通过偏光显微镜观察和电子探针成分分析,发现大岭上强过铝质花岗岩中存在三种类型的白云母,即原生白云母、交代型白云母和次生白云母;且岩相学特征各异。结合前人对原生与次生白云母的地球化学判别标志以及岩相学特征,认为交代型白云母应归属于原生白云母。大岭上强过铝质花岗岩结晶温度为801～872℃,指示其形成于地壳浅部,压力不大的条件下,且岩浆中水分、An组分（更长石）的存在导致岩浆白云母结晶时深度较浅,只有在聚敛构造环境下才能结晶出原生白云母等条件,推断出大岭上强过铝质花岗岩形成深度可能小于11～15 km。
Muscovite is one of the common rock-forming minerals,it distributes widely in granite,pegmatite,greisen and metamorphic rocks,and its forming process is restricted by many factors,so it has significant petrological significance. The muscovite of strongly peraluminous granite were selected in Dalingshang tungsten ore area,Jiangxi,and the phenomenon that there are three types of muscovite in strongly peraluminous granite,namely primary muscovite,metasomatic type muscovite and secondary muscovite is discovered by polarizing microscope and microprobe analysis,and the petrography characteristics of these types of muscovite varied remarkably. Combining with previous research of geological and geochemical criteria and petrography characteristics of primary and secondary muscovite,it hold that the metasomatic type muscovite belongs to primary muscovite. The crystallization temperature of Dalingshang strongly peraluminous granite is 801 ～ 872 ℃,and it is suggested that the granite formed in shallow crust and at low pressure. And the existences of water content in magma and An components（ oligoclase）lead to the condition that magmatic muscovite crystallized in low depths,and the primary muscovite can be crystallized only in convergent tectonic environment. It was inferred that the forming depths of Dalingshang strongly peraluminous granite may be less than 11 ～ 15 km.
出处
《科学技术与工程》
北大核心
2016年第11期22-29,共8页
Science Technology and Engineering
基金
国家科技支撑计划项目(2011BAB04B02)
国家重点基金项目(U1403292)联合资助
关键词
强过铝质花岗岩
原生白云母
次生白云母
大岭上
strongly peraluminous granites
primary muscovite
secondary muscovite
Dalingshang
