摘要
本文报道了新近在我国河南太平镇破碎带蚀变岩型轻稀土矿中发现的一个稀土氟化物矿物的矿物学特征。该矿物以集合体形式与氟铈矿、氟碳铈矿、氟碳钙铈矿、羟硅铈矿等紧密共生,手标本上为乳白至浅黄色,半透明,玻璃光泽,贝壳-不规则断口,不完全解理,白色条痕,性脆,摩氏硬度约为4~5,计算密度6. 07 g/cm^3;偏光显微镜下呈无色透明,粒状-板状,一轴晶,负光性,ω=1. 611,ε=1. 605。电子探针分析得出矿物的经验化学式为(La0. 48Ce0. 42Nd0. 07Pr0. 03) F2. 97;X射线单晶衍射分析表明,该矿物属于六方晶系,晶胞参数:a=0. 71400(4) nm,c=0. 72980(5) nm,Z=6,空间群P63cm(No.185);激光拉曼光谱特征峰主要包括228、308、370 cm^-1,应为La-F振动引起。上述特征与氟镧矿特征一致,从而确定该矿物为氟镧矿。这是该矿物在我国的首次报道。
Recently,it was discovered in altered rocks of the fracture zone in the Taipingzhen REE deposit,Henan Province,China in first time. It occurred as the REE mineral aggregates in close association with allanite-(Ce),gatelite-(Ce),cerite-(Ce),bastnasite-(Ce),synchysite-(Ce),fluocerite-(La),fluocerite-(Ce),etc. It is commonly semitransparent,with milky white to light yellow color,vitreous luster,conchoidal-irregular fracture,imperfect cleavage,white streak,fragility,about 4-5 Mohs' hardness,and the calculated density of 6. 07 g/cm^3. Under the optical polarizing microscope,it is colorless and transparent,with granular and platy forms. It belongs to uniaxial crystal with negative character,ω value of 1. 611,and ε value of 1. 605. Based on the calculation of its chemical composition by EPMA,the empirical formula should be(La0. 48 Ce0. 42 Nd0. 07 Pr0. 03) F2. 97.On the basis of the X-ray diffraction analysis of single crystal,the fluocerite-(La) belongs to hexagonal system,with crystal cell parameters of 0. 71400(4) nm for a,0. 72980(5) nm for c,6 for Z,the space group of P63 cm(No.185),and characteristic Laser Raman spectral peaks of 228,308,370 cm^-1 by the attribution of stretching vibrations of La-F. These features are very similar to those of the known natural and synthetic fluocerite-(La). Thus,it is the fluocerite-(La) discovered firstly in China.
作者
曲凯
司马献章
李国武
范光
李婷
郭虎
尹青青
李靖辉
QU Kai;SIMA Xian-zhang;LI Guo-wu;FAN Guang;LI Ting;GUO Hu;YIN Qing-qing;LI Jing-hui(Tianjin Center, China Geological Survey, Tianjin 300170, China;China University of Geosciences ( Beijing), Beijing 100083 , China;Beijing Research Institute of Uranium Geology, CNNC, Beijing 100029, China;Henan Nuclear Geological Bureau, Zhengzhou 450044, China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2019年第4期766-772,共7页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金资助项目(41502033)
中国地质调查地质矿产调查项目(DD20160129-03,1212011120771)
关键词
氟镧矿
稀土氟化物
矿物特征
太平镇稀土矿
fluocerite-( La)
REE fluoride
mineral characteristics
Taipingzhen REE deposit
