蒙阴金伯利岩中金云母的微组构特征及对岩浆演化的暗示  

The Microfabrics of Phlogopite from the Mengyin Kimberlites and their Implications to the Magma Evolution

作　　者：向正娇 杨志军 雷雪英[1] XIANG Zheng-jiao;YANG Zhi-jun;LEI Xue-ying(School of Earth Sciences and Engineering Sun Yat-sen University,Guangzhou 510275,China;Guangdong Provincial Key Lab of Geological Processes and Mineral Resource Survey,Guangzhou 510275,China)

机构地区：[1]中山大学地球科学与工程学院,广州510275 [2]广东省地质过程与矿产资源探查重点实验室,广州510275

出　　处：《矿物岩石地球化学通报》2020年第1期104-115,共12页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金项目(41373025,41073021)。

摘　　要：为探讨山东蒙阴金伯利岩的成因及其岩浆演化过程,采用SEM、EPMA和LA-ICP-MS对该区金伯利岩中金云母的微组构进行了分析研究。结果表明,该区岩浆成因金云母主要呈斑晶、显微斑晶和基质云母产出。根据主量元素(Al、Fe和Mg#)特征将金云母分为原生金伯利岩金云母组、金云母-钡镁脆云母组、金云母-四配位铁金云母组和金云母-黑云母共生组。早期金云母结晶后,在岩浆上升过程中受源条件或矿物相在熔体中再吸收的影响,向Ⅱ型基质云母、四配位铁金云母、钡镁脆云母演化。晚期通过岩浆改造或与围岩的交代变质作用形成金云母-黑云母巨晶共生组。综上认为,蒙阴金伯利岩岩浆成分受到了多种改造,其演化过程是相当复杂的。In order to figure out the genesis of the Mengyin kimberlites and evolution processes of the kimberlite magma,microfabrics of the phlogopites in the Mengyin kimberlites have been studied by using SEM,EPMA and LA-ICP-MS in this paper.The results show that magmatic phlogopites in the Mengyin Kimberlites occurred as phenocrysts,micro-phenocrysts and groundmass phase,respectively.According to the characteristics of major elements(Al,Fe and Mg#)of phlogopites,they can be classified into four types including the primary kimberlite phlogopite group;phlogopite-kinoshitalite group;phlogopite-tetraferriphlogopite group;and phlogopite-biotite macrocryst group.The early crystallized phlogopite,influenced by source conditions or mineral phase reabsorption of the melt,would be evolved toward three trends of the IItype groundmass mica,tetraferriphlogopite,and kinoshitalite during the magma ascent.In the late stage,the phlogopitebiotite macrocryst was formed due to the magmatic transformation or metamorphism with wall rocks.In summary,it is considered that the magmatic composition of the Mengyin kimberlites has been reformed in many ways,and the evolution process of the Mengyin kinmberlite magma is quite complicated.

关 键 词：金云母 微组构 岩浆演化 金伯利岩 山东蒙阴 

分 类 号：P578.959[天文地球—矿物学]