内蒙古黄岗梁含束状包裹体石榴石的矿物学特征研究  

Mineralogical Characteristic of Garnet Containing Sheaf-like Inclusion from Huanggangliang Deposit,Inner Mongolia

作　　者：史玉静 陈涛[1,2] 郑金宇 李星彤 张倩 SHI Yujing;CHEN Tao;ZHENG Jinyu;LI Xingtong;ZHANG Qian(Gemmological Institute,China University of Geosciences,Wuhan 430074,China;Hubei Gems and Jewelry Engineering Technology Research Center,Wuhan 430074,China;School of Earth Sciences,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)珠宝学院,湖北武汉430074 [2]湖北省珠宝工程技术研究中心,湖北武汉430074 [3]中国地质大学(武汉)地球科学学院,湖北武汉430074

出　　处：《宝石和宝石学杂志（中英文）》2023年第3期7-15,共9页Journal of Gems & Gemmology

基　　金：国家自然科学基金面上基金项目(42072252)。

摘　　要：石榴石中常有各种类型的包裹体。本文对产自内蒙黄岗梁地区含有束状包裹体的石榴石样品进行了常规矿物学测试、电子探针、拉曼光谱、红外光谱、紫外-可见光光谱、扫描电子显微镜和X射线能谱等测试分析,以获取该地区此类石榴石及其束状包裹体的矿物学特征。化学成分分析表明该地区此类石榴石为钙铁榴石,含有Mn、Ti、Mg、Cr等杂质元素;拉曼光谱分析显示特征钙铁榴石峰谱;该区此类钙铁榴石呈现深褐色-褐黄色,紫外-可见吸收光谱表明,Fe^(3+)在^(6)A_(1g)→^(4)A_(1g)^(4)Eg能级间的电子跃迁产生蓝紫区的438 nm吸收峰,其指示颜色主要由Fe^(3+)导致;该区钙铁榴石的红外光谱中吸收峰与[SiO_(4)]^(4-)振动和Fe^(3+)有关,不同样品中吸收峰的偏移是因其含有少量钙铝榴石和锰铝榴石引起的。石榴石样品的束状包裹体主要为浅褐色,一部分分布于六边形包裹体中,另一部分呈放射状、扇形分布,少数为丝状分布。扫描电子显微镜测试结果表明束状包裹体的横截面大多为近似圆形、矩形或三角形的空管,纵截面为长条状;部分充填有石英和方铅矿;六边形包裹体中存在富Al的环带。There are various types of inclusions in garnet.In this study,garnets containing sheaf-like inclusions from the Huanggangliang deposit,Inner Mongolia,were examined by conventional mineralogical tests,electron microprobe(EPMA),Raman spectrometer,infrared spectrometer(IR),ultraviolet-visible absorption spectrometer,scanning electron microscope(SEM)and X-ray energy spectrometer,to investigate the mineralogical characteristics of these garnet samples and their sheaf-like inclusions.The chemical composition analysis indicated that these garnet samples are andradite,which contain impurity elements including Mn,Ti,Mg and Cr.Raman spectra also indicated that these samples are andradite.Such garnets are dark brown-brown yellow.UV-Vis absorption spectra showed that the electron transition of Fe^(3+)between the energy levels of 6 A 1g→4 A 1g 4 E g produces a blue-violet absorption peak at 438 nm,which indicates that the colour is mainly caused by Fe^(3+).The absorption peak in the IR spectra is related to the vibration of[SiO 4]4-and Fe^(3+).The shift of absorption peaks in different samples is caused by the small amount of grossularite and spessartite.The sheaf-like inclusions in the samples are mainly light brown,some are distributed in hexagonal inclusions,others are radial and fan-shaped,and a few are filamentous.The results of SEM indicated that cross sections of the sheaf-like inclusions are mostly approximately circular,rectangular or triangular hollow channels and the longitudinal section is long strip;partly filled with quartz and galena.Al-rich zonation is found in hexagonal inclusions.

关 键 词：钙铁榴石 矿物学特征 包裹体 内蒙古黄岗梁 

分 类 号：P619.28[天文地球—矿床学] TS93[天文地球—地质学]