京西潭柘寺东山红庙岭组硬绿泥石矿物学研究

A Study on the Mineralogical Features of Chloritoid in Hongmiaoling Formation of Dongshan,Tanzhesi,West Beijing,China

利用偏光显微镜、X射线衍射(XRD)、拉曼光谱分析(Raman)、扫描电镜和能谱分析(SEM and EDS)等,从矿物学角度对潭柘寺东山红庙岭组中硬绿泥石特征进行了研究。结果表明,该区硬绿泥石属单斜晶系,发育接触双晶,呈玫瑰花状或束状集合体。硬绿泥石中有部分Fe2+被氧化为Fe3+,并替换了Al3+,其化学式可写为(Fe2+,Mg)(Al,Fe3+)2SiO5(OH)2。该区硬绿泥石与钠云母共存,形成温度为350～500℃,呈定向排列,为受构造应力影响而形成的应力矿物,其形成还可能与受构造控制的深部热液活动有关。

The mineralogical features of chloritoid in Hongmiaoling Formation of Dongshan,Tanzhesi,West Beijing,China were studied by using polarization microscope,X-ray diffraction（XRD）,Raman spectroscopy（Raman）,scanning electron microscope（SEM） and energy dispersive spectrometer（EDS）.The results show that,rose-like or fasciculate chloritoid in this area is monoclinic crystal with contact twin.Its chemical formula can be written as（Fe2＋,Mg）（Al,Fe3＋）2SiO5（OH）2 as Fe2＋ is oxidized to Fe3＋ and replaces Al3＋.Paragonite is found in the sample,indicating the metallogenic temperature of 350–500 ℃.The orientation of chloritoid shows that chloritoid is a stress mineral,and its formation may be related to the deeply structural controlled hydrothermal activities.