北京西山侏罗纪煤系硬绿泥石的矿物学特征  

Mineralogical study on Chloritoid from the Jurassic coal measures in western hills of Beijing

作　　者：李阔[1] 刘钦甫[1] 胡媛[1] 侯子健 胡鲁昌 

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083

出　　处：《湖南科技大学学报（自然科学版）》2014年第2期94-98,共5页Journal of Hunan University of Science And Technology：Natural Science Edition

基　　金：国家自然科学基金资助项目(41072119);北京市共建项目(20121141301);中国矿业大学(北京)煤炭资源与安全开采国家重点实验室大学生创新计划项目

摘　　要：通过偏光显微镜,X射线衍射,傅里叶变换红外光谱和电子探针等手段对北京西山潘涧沟侏罗纪窑坡组底部的硬绿泥石泥岩进行分析.研究发现,硬绿泥石与硬水铝石,0.7 nm绿泥石,叶蜡石,伊利石共生.偏光显微镜下硬绿泥石呈菊花状集合体,{001}解理缝和(010)裂理都十分发育,正交光下干涉色为一级灰.通过X射线衍射结果分析得出其为单斜晶系,晶胞常数为a=0.948 728 nm,b=0.543 418 nm,c=1.811 236 nm,β=102.019 1°.电子探针数据计算其化学式为(Fe2+1.93Mn0.33Ti0.06)Al3.92Si2.11O12.18.研究表明,中生代末期房山花岗岩侵入窑坡组底部地层,在岩浆热变质作用下窑坡组底部岩层结晶出硬绿泥石.Chloritoid,collected from the argillite in the bottom of Yaopo Formation of Western Hills of Beijing,was studied based on the polarizing microscope,X -ray diffraction combined with Fourier infrared spectroscopy and electron probe.The results show that chlotitoid is in paragenesis with diaspore,0.7 nm chlorite,pyrophyllite and illite.Chloritoid under polarized microscope is in the shape of chrysanthemum-like, radial and bundle.Its {001}cleavage and （010）partings are obvious,and the interference colour is the first order grey under the cross -polarizer.The X -ray diffraction pattern indicates this mineral as monoclinic syngony.Its cell parameters are calculated as a=0.948 728 nm,b=0.543 418 nm,c=1.811 236 nm,β=102. 019 1°.Its chemical formula can be written as （Fe2＋1.93Mn0.33Ti0.06）Al3.92Si2.11O12.18 base on the electron probe data.The research shows that the chloritoid was formed by magmatic thermal metamorphism when granite intruded in the bottom of Yaopo Formation in the late Mesozoic.

关 键 词：北京西山 窑坡组 硬绿泥石 热变质 

分 类 号：P571[天文地球—矿物学]