摘要
金沙江蛇绿岩带绒角蛇绿岩由超镁铁岩与异剥辉长岩岩脉组成,在蛇绿岩就位过程中,异剥辉长岩岩脉碎裂为不规则的岩块包裹于超镁铁岩中,形成超镁铁岩中的构造包体。经过交代蚀变作用,超镁铁岩形成蛇纹岩,异剥辉长岩形成异剥钙榴岩。异剥钙榴岩的形成是超镁铁岩蛇纹石化和异剥辉长岩中斜长石钙铝榴石化循环作用的结果,并与对蛇绿岩起过作用的构造运动有关系,是变形作用伴随交代作用的产物。绒角蛇绿岩中的异剥钙榴岩的发现,说明金沙江蛇绿岩带不存在榴辉岩,其变质相属葡萄石-绿泥石低温低压相,也说明金沙江蛇绿岩带是洋壳残片"冷侵入"的产物。
The Rongjiao ophiolite consists of ultra-mafic rocks and diallage gabbroic veins in Jinshajiang ophiolite belt. During emplacement of ophiolite,the diallage gabbroic veins are fractured into irregular rock mass enclosed by ultra-mafic rocks. The ultra-mafic rocks and diallage gabbro are turned into serpentinite and rodingites through metasomatism and alteration. Formaiton of rodingites are resulted from serpentinization of ultra-mafic rocks and grossularization of plagioclase in diallage gabbro and related to tectonism imposed on ophiolite. Therfore, the rodingites is formed in the course of deformation and metasomatism.Occurrence of rodingites in the Rongjiao ophiolite proves that there is not eclogite in Jinshajiang ophiolite belt which belong to prehnite-chlorite low-grade metamorphic facies and Jinshajiang ophiolite belt is resulted from the cold emplacement of residual piece of oceanic crust.
出处
《矿物岩石》
CAS
CSCD
北大核心
2003年第4期70-73,共4页
Mineralogy and Petrology
基金
国土资源部"九.五"攻关项目(95-02-001-03)
