多硅白云母中Fe^（2＋）的高压有序效应  

Fe￣(2+) ORDER RESULTING FROM HIGH METAMORPHIC PRESSURE IN PHENGITE

作　　者：应有浦 宋仁奎[1] 赫伟[1] 

机构地区：[1]中国科学院地质研究所

出　　处：《地质科学》1995年第4期355-362,共8页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金

摘　　要：２１个多硅白云母来自４个低温高压变质带。用电子探针、Ｘ射线粉末衍射及穆斯堡尔谱测定其化学成分、ｂ０值及Ｆｅ２＋占位。建立Ｆｅ２＋（Ｍ１）／Ｆｅ２＋（Ｍ２）对ｂ０值相关图，发现Ｆｅ２＋在八面体晶位有序化并解释其有序机理。amples of phengite used for present work were collected from 4 low-temperature and high-pressure metamorphic belts in China. The chemical compositions, b0value and Fe2+ site occupancy have been measured by means of electron microprobe,X-ray powder diffraction and Mossbauer spectrometer. The ratio, R=Fe2+ (M1)/Fe2+(M2), is used to describe Fe2+ order degree in phengite. b0 vs R diagram has been established, in which there are 3 regions corresponding to low-, medium- and highpressure. This is a new geobarometric indicator. Mechanism of Fe2+ order at M2 site of phengite have been discussed. Progress of Fe2+ order at M2 site of phengite is suggested: high metamorphic pressure→Tschermarks substitution → (1) Si4+ replace tetrahedral Al3+, more Si enter phengite structure, (2) (Mg, Fe) replace Al3+ at M2site, which results in Fe2+ order at M2.

关 键 词：多硅白云母 铁离子 有序效 应压 白云母 

分 类 号：P578.959[天文地球—矿物学]