西藏蛇绿岩中硅铁合金组合及成因探讨  

Si-Fe alloy assemblage in ophiolite of Tibet and their genesis

作　　者：白文吉[1] 杨经绥[1] 陶淑凤[2] 施倪承[3] 方青松[1] 马生 颜秉刚[1] 熊明[3] 代明泉[3] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]北京矿冶研究总院,北京100044 [3]中国地质大学X射线衍射分析室,北京100083

出　　处：《岩石矿物学杂志》2003年第3期279-284,共6页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目 (49972 0 73)

摘　　要：在雅鲁藏布江蛇绿岩带的东端罗布莎蛇绿岩的铬铁矿中发现不寻常的硅铁合金组合。 4种硅铁合金的理论分子式分别为Fe0 .84 Si2 .0 0 (Fe3 Si7)、Fe7Si3 、Fe6Si4 以及Fe4 Ti3 Si2 P。这些合金均选自铬铁矿石的人工重砂中 ,在少数颗粒中见到由 3种硅铁合金组成的交生结构 ,明显表明这些合金的同生和同成因性。推测它们为化学反应成因 ,来自于核幔边界地带。Four unusual varieties of Si-Fe alloys occur in ophiolite along the Yarlung Zangbo River. Podiform chromite deposits are distributed in the hurzburgite facies of the Luobusa ophiolite. The Si-Fe alloys are composed chemically of Fe 3Si 7, Fe 7Si 3, Fe 6Si 4, and Fe 4Ti 3Si 2P, and the associated minerals comprising Fe, FeO, SiO 2, Si and Mg silicates occur in chromitite. The intergrowth texture formed by 3 alloys indicate that these alloys have same genesis, and the texture developed in the Si-Fe alloys might be a product of chemical reaction between liquid iron and silicate on the boundary of mantle and core.

关 键 词：硅铁合金 交生结构 成因 蛇绿岩 西藏 

分 类 号：P578.12[天文地球—矿物学]