京西羊屎沟变质矿物组合及变质带

接触热变质带的划分对变质岩变质过程的研究提供了有力的依据。基于京西羊屎沟地区地层中变质矿物组合及其空间分布情况，对该区的接触热变质带进行划分，并分析变质作用的形成阶段。由于燕山期房山岩浆岩体侵入，使围岩发生不同程度的接触热变质作用，形成各种特征变质矿物。在特定岩石类型中，特征变质矿物有规律的组合。采用偏光显微镜透射法和X射线衍射分析，分为透辉石-透闪石带、二云母带、红柱石白云母带和绢云母带，表明距离岩体由近至远，岩石变质程度由高到低呈分带现象。伴随着岩浆侵入不同阶段形成不同的特征变质矿物，将接触热变质作用分为5个渐进的阶段。 

Metamorphic mineral assemblage and metamorphic zones of Yangshigou area in western Beijing

The division of contact thermal metamorphic zones provides a strong basis for the study of metamorphic processes. According to metamorphic mineral assemblage of Yangshigou in western Beijing and its spatial distribution in strata, the contact thermal metamorphic zones of this area is divided and the formation stages of metamorphism were analyzed. Due to the intrusion of the Fangshan magmatic rock, surrounding rocks suffered from different degree of contact thermal metamorphism, which formed various metamorphic minerals. In particular types of rocks, there are regular combinations of characteristic metamorphic minerals. Using polarizing microscope and X-ray fluorescence spectroscopy, it is divided into the diopside-tremolite zone, the mica zone, the andalusite zone and the sericite zone, indicating that the degree of rock metamorphism decreased with the distance from magmaticrock.With the formation of different metamorphic minerals at different stages of magmatic intrusion, the contact thermal metamorphism is divided into five progressive stages.