洪古勒楞蛇绿岩中斜长石的化学成分特征  

CHEMICAL COMPOSITION OF PLAGIOCLASES IN. HONGGULELENG OPHIOLITE, XINJIANG, CHINA

作　　者：白文吉[1] 周美付[1] 

机构地区：[1]中国地质科学院地质研究所

出　　处：《矿物岩石》1989年第1期6-14,共9页Mineralogy and Petrology

摘　　要：洪古勒楞蛇绿岩中保存比较新鲜的斜长石,其化学成分与寄生岩石有关,具有宽的变化范围。斜长石中的Al_2O_3与CaO;SiO_2与Na_2O;MgO与FeO具正相关关系,在(SiO_2+Na_2O)—(FeO+MgO)×100—(CaO+Al_2O_3)图解上,堆积岩的斜长石富Al_2O_3、CaO、Cr_2O_3、NiO和TiO_2,火山岩的富SiO_2和Na_2O或MgO和K_2O。斜长石是堆积岩的主要含稀土元素的矿物,具正Eu异常的稀土分布模式。但火山岩中的斜长石没有Eu异常的特点。斜长石的Eu异常特点受其形成环境控制。Chemical composition of plagioclases, which are relatively fresh in the Hongguleleng ophiolite, significantly varies with the types of their host rocks.Al_2O_3 and CaO, SiO_2 and Na_2O, MgO and FeO are in close positive correlations.On the diagram of (SiO_2 + Na_2O)—(FeO+MgO) × 100—(CaO + A1_2O_3) plagioclases of cumulative rocks are distinct from those of volcanic rocks. Plagioclases in the cumulates are rich in A1_2O_3, CaO, Cr_2O_3, NiO and TiO_2, while plagioclases in volcanics are rich in SiO_2 and Na_2 O or MgO and K_2O. Plagioclases are main minerals which bear REE for the cumulates,having a clear Eu abnomality. Plagioclases in the volcanic rocks have no abnormal Eu.The abnormal characteristics of Eu in plagioclases are controlled by their rock-forming environment.

关 键 词：蛇绿岩 斜长石 稀土元素 寄生岩石 

分 类 号：P578.968[天文地球—矿物学]