Dickite as a type of clay mineral that is utilized in industries such as papers,ceramics,paints,cosmetics and fillers is widely distributed in Zijinshan(ZJS) Au-Cu deposit in southeastern China.In this paper,three typ...Dickite as a type of clay mineral that is utilized in industries such as papers,ceramics,paints,cosmetics and fillers is widely distributed in Zijinshan(ZJS) Au-Cu deposit in southeastern China.In this paper,three types of dickites(i.e.,transparent,translucent and opaque),which were selected by optical microscopy,were investigated by X-ray diffraction(XRD)-Rietveld method based on the EVA and TOPAS softwares.The results show that transparent dickite is lowly ordered and poorly crystallized.Compared to other two dickites,the transparent one has a lower value of DC index and thinner average flake thickness along c-axis.Furthermore,the crystal structure of transparent dickite has a greater number of distortions of[SiO_4]tetrahedron and[AlO_6]octahedron,compared to that of translucent and opaquedickites.The results by the XRD-Rietveld method were confirmed by field emission scanning electron microscopy(FESEM) and electron probe micro-analysis(EPMA).Therefore,transparent dickite with low degree of order and irregular particle shape is not suitable for use in ceramic industry.展开更多
The rocks of the Zhenzhuchong Member of the Ziliujing Formation,JiulongshaneJiange area in the Sichuan Basin,were analyzed by petrography,XRD,and SEM techniques to investigate their diagenetic history and properties,s...The rocks of the Zhenzhuchong Member of the Ziliujing Formation,JiulongshaneJiange area in the Sichuan Basin,were analyzed by petrography,XRD,and SEM techniques to investigate their diagenetic history and properties,such as authigenic mineral types,evolution of mixed-layer illiteesmectite minerals,the clay assembly,and the fraction of mixed-layer clay minerals.The results revealed that the Zhenzhuchong Member has experienced several important episodes of diagenetic alteration since the deposition,including compaction(pressuresolution),cementation,metasomatism,dissolution,fracturing,and infilling of caves and cracks.It was also observed that diagenetic properties of the Jiulongshan area were significantly different from those of the Jiange area.The rock samples from the Jiulongshan area were characterized by the composition of siliceous and calcareous cements,varying amounts of detrital grains,clay matrix and kaolinite replaced by calcites,a certain amount of rarely dissolved early-stage kaolinite,dickite,and infillings by late-stage calcite.On the other hand,for the rock samples from the Jiange area,the dissolution is a common phenomenon with features of abundant aluminosilicates-dissolution pores or components,but the replacement phenomenon has rarely been seen.These rock samples were characterized by the presence of clay mineral cements,quartz,and dolomite infillings.It indicated that there was a great difference of diagenesis between the two areas in the types,phase,and temperature of diagenetic fluids.Revealing the difference would provide theoretical and practical implications for the exploration of high quality oil and gas reservoirs.展开更多
基金supported by the Fundamental Research Funds for the Fuzhou Universitiesthe Natural Science Foundation of China(41002016)
文摘Dickite as a type of clay mineral that is utilized in industries such as papers,ceramics,paints,cosmetics and fillers is widely distributed in Zijinshan(ZJS) Au-Cu deposit in southeastern China.In this paper,three types of dickites(i.e.,transparent,translucent and opaque),which were selected by optical microscopy,were investigated by X-ray diffraction(XRD)-Rietveld method based on the EVA and TOPAS softwares.The results show that transparent dickite is lowly ordered and poorly crystallized.Compared to other two dickites,the transparent one has a lower value of DC index and thinner average flake thickness along c-axis.Furthermore,the crystal structure of transparent dickite has a greater number of distortions of[SiO_4]tetrahedron and[AlO_6]octahedron,compared to that of translucent and opaquedickites.The results by the XRD-Rietveld method were confirmed by field emission scanning electron microscopy(FESEM) and electron probe micro-analysis(EPMA).Therefore,transparent dickite with low degree of order and irregular particle shape is not suitable for use in ceramic industry.
基金support from Doctor Subject Foundation of the Ministry of Education of the People's Republic of China(No.20115122110002)is gratefully acknowledged.
文摘The rocks of the Zhenzhuchong Member of the Ziliujing Formation,JiulongshaneJiange area in the Sichuan Basin,were analyzed by petrography,XRD,and SEM techniques to investigate their diagenetic history and properties,such as authigenic mineral types,evolution of mixed-layer illiteesmectite minerals,the clay assembly,and the fraction of mixed-layer clay minerals.The results revealed that the Zhenzhuchong Member has experienced several important episodes of diagenetic alteration since the deposition,including compaction(pressuresolution),cementation,metasomatism,dissolution,fracturing,and infilling of caves and cracks.It was also observed that diagenetic properties of the Jiulongshan area were significantly different from those of the Jiange area.The rock samples from the Jiulongshan area were characterized by the composition of siliceous and calcareous cements,varying amounts of detrital grains,clay matrix and kaolinite replaced by calcites,a certain amount of rarely dissolved early-stage kaolinite,dickite,and infillings by late-stage calcite.On the other hand,for the rock samples from the Jiange area,the dissolution is a common phenomenon with features of abundant aluminosilicates-dissolution pores or components,but the replacement phenomenon has rarely been seen.These rock samples were characterized by the presence of clay mineral cements,quartz,and dolomite infillings.It indicated that there was a great difference of diagenesis between the two areas in the types,phase,and temperature of diagenetic fluids.Revealing the difference would provide theoretical and practical implications for the exploration of high quality oil and gas reservoirs.
