南极拉斯曼丘陵长英质片麻岩中夕线石的出溶现象  

The exsolution assemblage of sillimanite in quartzofeldspathic gneiss of the Larsemann Hills,East Antarctica

作　　者：任留东[1] 王彦斌[1] 刘晓春[2] 赵越[2] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质科学院地质力学研究所,北京100081

出　　处：《岩石矿物学杂志》2008年第6期524-528,共5页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目(40572041);地质调查资助项目(1212010511505);国土资源部百名优秀青年科技人才资助项目;所长基金资助项目

摘　　要：南极拉斯曼丘陵长英质片麻岩中的粗粒夕线石可能有内部出溶现象,出溶形成的矿物有磁铁矿、钛铁矿-赤铁矿和石英出溶矿物条纹,并有少量的斜方辉石。电子探针成分分析表明,本区夕线石高温结晶时不仅有Fe3+,可能还有Fe2+、Mg2+和Ti4+的替换,铁氧化物质量分数可高达2.9%;随着温度的不断降低,固溶体互溶度也不断减小,大部分微量组分从夕线石中析出形成出溶结构,而且低温变体中稳定的替换元素以Fe3+为主。铁组分的类质同像替换对物理化学计算和夕线石矿化环境均有所影响,对夕线石晶胞参数a的影响很小,而对b,尤其对c的影响较大,与前人的结论有所不同。The exsolution assemblage of sillimanite from quartzofeldspathic gneiss in the Larsemann Hills of East Antarctica consists of magnetite, ilmenite-hematite and quartz exsolution laminae and minor orthopyroxene. A compositional analysis shows that the sillimanite primarily crystallized at high temperature has not only Fe^3 ＋ but also Fe^2＋ , Mg^2＋ and Ti^4＋ substitutes. Iron oxides can be as high as 2.9%. With the decreasing temperature, tion in sillimanite has an insignificant effect on a but a substantial effect on b, especially on c values of the crystal cell lattice. These results are to some extent contradictory to the previous conclusions.

关 键 词：夕线石 出溶 铁组分替换 晶胞参数 南极拉斯曼丘陵 

分 类 号：P588.345[天文地球—岩石学] P578.945[天文地球—地质学]