内蒙古头道桥地区蓝闪石片岩和相关变质岩石岩石学特征及其构造意义  

Character of Blueschist and Related Metamorphic Rocks from the Toudaoqiao Area,Inner Mongolia and Its Tectonic Implication

作　　者：赵立敏[1] 刘永江[1] 滕加雨 李伟民[1] Zhao Limin;Liu Yongjiang;Teng Jiayu;Li Weimin(College of Earth Sciences, Jilin University, Changchun 130061, China;The First Geologic Survey of Jilin Province, Changchun 130033, China)

机构地区：[1]吉林大学地球科学学院,长春130061 [2]吉林省第一地质调查所,长春130033

出　　处：《吉林大学学报（地球科学版）》2018年第2期534-544,共11页Journal of Jilin University：Earth Science Edition

基　　金：国家重点基础研究发展计划("973"计划)项目(2013CB429802);国家自然科学基金项目(41302175)~~

摘　　要：内蒙古头道桥地区出露了一套经高压变质形成的岩石组合。本次研究通过岩相学和矿物化学分析,根据矿物组合的不同,识别出蓝片岩、绿片岩两种不同类型的岩石类型。其中,蓝片岩的矿物组合为角闪石(蓝闪石、蓝透闪石)+绿帘石+钠长石+绿泥石+石英+赤铁矿±多硅白云母±方解石±榍石;绿片岩的矿物组合为绿泥石+钠长石+石英±绿帘石±角闪石(阳起石、镁角闪石、蓝透闪石、冻蓝闪石等)±多硅白云母±赤铁矿。确定了蓝片岩的峰期变质级别为绿帘-蓝闪片岩相,峰期变质温度为400~600℃,压力为1.2~1.4GPa。绿片岩的峰期变质级别为绿帘-角闪岩相。结合前人研究成果,认为蓝片岩和绿片岩的形成与额尔古纳地块和兴安地块的碰撞拼合有关。A set of high pressure metamorphic rocks are exposed in the Toudaoqiao area,Inner Mongolia.In this study,the investigations on petrography and mineral chemistry are carried out,and two types of metamorphic rocks are classified to blueschist and greenschist on the basis of the mineral assemblages.The mineral assemblage of the blueschist is amphibole+epidote+albite+chlorite+quartz+hematite±phengite±calcite±titanite,and the mineral assemblage of the greenschist is chlorite+albite+quartz±amphibole±epidote±phengite±hematite.The blueschists were suffered from the epidote-blueschist facies metamorphism,with the peak metamorphic conditions of T=400-600℃,p=1.2-1.4GPa.The greenschists were suffered from the epidote-amphibole facies metamorphism.According to the previous geochronology data,the high pressure blueschist and greenschist are related to the suture zone between Eerguna and Xing’an massifs.

关 键 词：头道桥地区 蓝片岩 绿片岩 高压变质 缝合带 

分 类 号：P59[天文地球—地球化学]