广东新田断裂中碱性长石类矿物相变现象初探

PRELIMINARY RESEARCH ON THE FACIES CHANGE OF ALKALI-FELDSPARS FROM THE XINTIAN FAULT ZONE,GUANGDONG PROVINCE

本文以新田断裂为例,阐述了在构造动力作用下,花岗质构造岩中碱性长石的出溶和交代作用所引起的矿物相变。笔者主要从显微镜下的研究入手,分析正长石、微斜长石、条纹长石在不同构造岩相带中出现的频率和特征,在总结实验资料的基础上,对压扭性断裂带中碱性长石类矿物的相变现象进行探讨,并提出了矿物相变规律的初步看法。

From the mineral facies change angle,we can to study of frequency of the presence of al- kali-feldspar and their features under compresso-shear stress in terms of facies change aiming at tracing the character,intensity and mechanism of the applied stress,will be helpful to the in- vestigation of the dynamic formation of rocks and minerals. The author found that the alkali-feldspars from the fault zone of the granite terrain had undergone notable facies change.The successive presence of orthoclase,microcline and perthite in the compresso-shear zone is well correlated to the zonal distribution of increasing dynamic force. There is a regular change in crystal texture and physical property of the alkali-feldspars. This can serve as an indicator of their tectonic origin,useful for an estimation of the tectono- chemical conditions of their formation. The manner of application of dynamic force its character and intensity is mainly responsi- ble for the facies change of alkali-feldspars by exsolution,replacement and sliding.Generally, microclines will be predominant in the dynamically weak zone and perthites in the strong zone.