用接触变质作用标志初步判别北京房山岩体的岩浆侵位机制  

Using Contact Metamorphic Criteria in Contact Aureole to Preliminarily Discriminate Magma Emplacement Mechanisms of Fangshan Pluton,Beijing

作　　者：陈能松[1] 陈冰寒 Roger Mason 杨婷婷 夏彬 刘嵘[1] 王国庆[1] 徐冉[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074

出　　处：《地球科学》2018年第1期99-108,共10页Earth Science

基　　金：国家自然科学基金项目(No.41672060); 中国地质大学(武汉)本科教学工程项目(No.ZL201610).

摘　　要：近同心状房山岩体接触变质晕中变斑晶-基质关系与变质作用P-T轨迹样式的结合可以区分岩浆底劈式侵位与气球膨胀式侵位机制.例如,该房山岩体南侧接触变质晕中的下马岭组泥质变质岩的变斑晶-基质关系显示强烈的面状压扁应变变形,其变质作用P-T轨迹具等压加热趋势,综合前人成果估算该岩体4个依次侵位的岩石单元的最终就位岩浆结晶深度彼此近于一致,倾向于认为该岩体的岩浆侵位机制为气球膨胀式.Relationship between metamorphic porphyroblasts and their matrices in the contact aureole of the concentric zoned Fangshan pluton,Beijing,combined with P-T patterns can be used as criteria to distinguish between magmatic diapirism and balloon expansion mechanisms for pluton emplacement in this study.It is found that,pelitic metamorphic rocks in the Xiamaling Formation in the southern part of the aureole display porphyroblast-matrix relationships reflecting intense plane-strain deformation combined with a nearly isobaric heating P-T trajectory towards the contact.Incorporating previously published estimates of final crystallization depths of four successively emplaced magmatic units,the results favor the balloon-inflation intrusion mechanism.

关 键 词：岩浆侵位机制 接触变质作用 P-T轨迹 变斑晶-基质关系 房山岩体 岩石学 

分 类 号：P581[天文地球—岩石学]