辽北太古宙变质岩中的振荡型矿物环带及意义

对辽北太古宙层状变质岩系中石榴石、黑云母的成分分析发现,其中存在明显的振荡型矿物环带。对其形成机理的研究表明,这是矿物在结晶过程中由于偏离理想状态而形成的一种非平衡态自组织现象,即耗散结构。矿物内部成分的振荡性并不是由于外界条件的周期变化所造成的,而是体系内部固有属性的反映。这种认识对研究变质作用的动力学过程具有重要的借鉴意义,文中还就这种振荡性矿物环带在变质作用研究中的意义作了进一步的阐述。

Oscillatory Zoning in Minerals from Metamorphic Rocks of Northern Liaoning and Its Significance

A study of garnet and biotite from Archean stratified metamorphic rocksin northern Liaoning shows that these two minerals exhibit oscillatory zoningin chemical composition, especially in the ratio of Mg to Mg + Fe. An investi-gation into their growth process reveals that such zoning is a nonequilibriumself--organization or dissipative structure formed as a result of a nonideal sta-te of these minetals during Archean metamorphism. The oscillatory variationin chemical composition of minerals is an intrinsic characteristic of the petro-chemical system under noneguilibrium conditions instead of resulting fromperiodic changes in such external conditions as temperature and pressure. In addition, the significance of oscillatory zoning in minerals in the studyof metamorphism is discussed in detail in this paper.