超晶格正长石的高分辨透射电子显微镜研究

HRTEM STUDY OF THE SUPERLATTICE ORTHOCLASE

对产自山东五莲辉石二长岩中的正长石进行了高分辨透射电子显微镜(HRTEM)研究,确定这一正长石属大周期超晶格正长石。其扩展晶胞参数与三斜亚晶胞参数间的关系为α=α_(tc),b≈8b_(tc),c=c_(tc),β=β_(tc)(下标tc表示三斜亚晶胞)。 这一超晶格正长石是由一系列的三斜晶畴组成。它是钾长石从C2/m对称向Cl对称的相变过程中,通过四面体中Si-Al间的有序化而形成的一种中间态调制结构。

An HRTEM study was carried out for the orthoclase (Or_(65) Ab_(21) An_(11)) taken from the augite-mozonite deposit in Wuliang, Shandong Province. The results showed that this material consists of superlattice with long period. The relationship between extended cell parameter and triclinic subcell parameter is as follows: a=a_(tc), b = 8d_(010)≈8b_(tc) c= c_(tc), β= β=(tc) (tc represents the triclinic subcell). The orthoclase consists of a series of triclinic domains. It is the intermediate modulated structure formed in the process of phase transformation of potassic feldspar horn C2/m symmetry to C1 Symmetry through the ordering of Si and Al in the te-terahedra.