| 平武板状绿柱石{0001}晶面的溶蚀像特征与晶体生长 |
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| 引用本文： | 张良钜,阮青锋,饶灿.平武板状绿柱石{0001}晶面的溶蚀像特征与晶体生长[J].矿物学报,2012(1):1-8,171. |
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| 作者姓名： | 张良钜 阮青锋 饶灿 |
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| 作者单位： | 桂林理工大学地球科学学院;广西地质工程中心重点实验室;南京大学地球科学系 |
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| 基金项目： | 国家自然科学基金项目(批准号:40572026;41172054);有色及贵金属隐伏矿床勘查教育部工程研究中心建设项目(教技函[2007]72号) |
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| 摘 要： | 板状绿柱石产于花岗岩云英岩化边部或晶洞壁的白云母-钠长石-绿柱石-水晶的矿物组合中,钠长石呈自形晶,绿柱石的洁净度与透明度相对较差。晶体测量表明,晶体的单形晶面发育依次为c{0001}→s{11 2-1}→p{10 1-1}→m{10 1-0}→v{21 3-1}、n{45 9-4}、a{11 2-0}。微分干涉显微镜(DIC)及扫描电镜(SEM)研究表明:各单形晶面上生长纹(微形貌)反映面网结构的对称性,c{0001}单形晶面上的六边形溶蚀坑(50～170μm)是由平行晶体C轴的各单形晶面生长层从晶体中心向外叠堆组成,层生长机理制约晶体生长全过程,平行双面(c)的生长层较薄(5～8μm)且较稳定,六方双锥(s)生长层较厚且圆滑,六方柱(m)生长层由晶体中心往外其厚度由厚逐渐变薄(12～20μm),台间隔由窄变宽。晶体溶蚀是从面网密度最大的c{0001}开始,溶蚀面积依平行双面(c)、六方双锥(s)单形晶面由大变小,六方柱(a)、复六方双锥(v、n)单形晶面因面网密度小而未受到溶蚀。据矿物共生组合、流体包裹体均一法测量与拉曼光谱(LRS)分析表明板状绿柱石是在中–高温(303℃)、过饱和度较大、成矿介质的钠长石化发育且热动力环境相对稳定的条件下形成,气液包裹体主要由H2O、CO2及微量CH4、N2组成,CO2及微量CH4、N2可能与碳酸盐围岩有关。
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| 关 键 词： | 板状绿柱石 表面微形貌 层生长机理 溶蚀像成因 四川平武 |
The Crystal Growth and Characteristics of Etched Figures on c{0001} Face of Tabular Beryl Crystal from Pinwu,China |
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| ZHANG Liang-ju,RUAN Qing-feng,RAO Can.The Crystal Growth and Characteristics of Etched Figures on c{0001} Face of Tabular Beryl Crystal from Pinwu,China[J].Acta Mineralogica Sinica,2012(1):1-8,171. |
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| Authors: | ZHANG Liang-ju RUAN Qing-feng RAO Can |
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| Institution: | 1.College of Earth Science,Guilin University of Technology,Guilin 541004,China; 2.Key Laboratory of Geological Engineering Center of Guangxi Province,Guilin 541004,China; 3.Department of Earth Sciences,Nanjing University,Nanjing 210093,China) |
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| Abstract: | Beryl occurred in mineral association of granite greisened muscovite,albite,beryl and quartz.Goniometry indicated that the single form crystal face growth is in turn c{0001},s{112-1},p{101-1},m{101-0} and v{213-1},the next place is n{459-4} and a{112-0}.There are some growth pattern(surface micromorphology) in different single form crystal face is observed by differential interference phase contrast microscope(DIC) and scanning electron microscopy(SEM),and those growth pattern have related to the net structure symmetry.Pinacoidgrowth layer thickness is the thinnest(about 5~8 μm) and the growth layer is stablest,the hexagonal prism growth layer is thick(about 12~20 μm) and it is gradually change from thick to thin,the width of the hexagonal prism growth layer is change from narrow to broaden.Layer growth mechanism controlled the crystal growing of beryl.On the single form crystal face c{0001},hexagonal etch pit is construction by different single form crystal face growth layer outward parallel folds from the crystal center.The etching is started from the single form c{0001},the biggest reticular density in all net,and the etching area is proportional with different reticular density.The etching area on pinacoid is bigger than that on hexagonal bipyramid single form crystal face,but the hexagonal prism(a) and the dihexagonal bipyramid(v & n) single form crystal face has not been etched because of the smaller reticular density.The fluid inclusion temperatures tested by homogenous method and ingredient analysis by laser Raman spectroscope(LRS) all revealed that the tabular beryl has grown in medium-high temperature(about 303 ℃)and stabling thermodynamics,the gas and the liquid inclusion mainly composed by H2O,CO2 and micro CH4,N2.CO2 and micro CH4,N2 possible concerns to the carbonate wallrock. |
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| Keywords: | tabular beryl surface microtopography layer growth mechanism etched figures genesis Pinwu Sichuan |
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