中文摘要：

采用偏光显微镜、傅里叶红外光谱分析和x射线荧光光谱等手段对北京西山羊屎沟地区红柱石矿物学特征以及成因进行相关分析。研究发现，该区红柱石主要呈4种矿物组合存在于含矿岩石中：①红柱石组合；②黑云母一红柱石组合；③白云母／绢云母一红柱石组合；④石榴子石一红柱石组合，表明岩石变质程度由低到高变化。红柱石横截面发育“X”型裂理和环带状显微变形构造，反映了红柱石的结晶形成是与构造变形同期进行的。该区红柱石形成是房山岩体侵入过程中，富硅的碱性流体侵入泥质围岩发生物质交换和反应形成的，形成温度在500-550℃之间，压力〈500MPa。

英文摘要：

Polarizing microscope, Fourier infrared spectroscopy and X-ray fluorescence spectroscopy were used to study the mineralogical characteristics and genesis of andalusite in area of Yangshigou in western Beijing, China. Results indicate that there are four kinds mineral assemblage of andalusites presented in the ore-bearing rocks： ①andalusite alone; ② biotite andalusite assemblage; ③muscovite/sericite andalusite assemblage; ④garnet-andalusite assemblage, meaning that the degree of metamorphism of rocks varies from low to high. The ＂X＂-shaped fractal and ring-shaped microstructural development of the andalusite cross section show that the crystallization of andalusite forms synchronously with structural deformation. The formation of andalusite in this area profits from exchange and reaction of alkali-rich fluids into the argillaceous rocks during the intrusion of the Fangshan magmatie rock. Andalusite forms under a low temperature（500-550 ℃ ）and a low pressure （ 〈500 MPa） condition.