Application of Glauconite in Sedimentary Geochronology  

作　　者：于荣炳 

机构地区：[1]Tianjin Institute of Geology and Mineral Resources

出　　处：《Chinese Journal Of Geochemistry》1989年第3期283-291,共9页中国地球化学学报

摘　　要：Glauconite is widely distributed in space and time.In China glauconite-bearing strata are extensive occurrence ranging from Late Cretaceous to Middle Proterozoic in age.X-ray powder analysis,X-ray diffracition analysis and differential thermal analysis revealed that glauconite has a mica-type structure between dioctahedron and trioctahedron.Its chemical composition is:Al2O310.6%,SiO249.23%,MgO3.24%,Fe2O317.40%,FeO1.8%,and K2O7.92%,Its crystal form and thermal properties are very similar to those of mica-like clay minerls.According to isotopic age determinations of glauconite in modern oceans (including the East China Sea,the South China Sea and the Yellow Sea),we consider that in the extreme case glauconite is an authigenic mineral.It is generally formed in sedimentary rocks.Is has further proved that glauconite can be used to determine the ages of sedimentary rocks.Glauconite is widely distributed in space and time.In China glauconite-bearing strata are of extensive occurrence ranging from Late Cretaceous to Middle Proterozoic in age.X-ray powder analysis,X-ray diffraction analysis and differential thermal analysis revealed that glauconite has a mica-type structure be- tween dioctahedron and trioctahedron.Its chemical composition is:Al_2O_3 10.67%,SiO_2 49.23%,MgO 3.24%,Fe_2O_3 17.40%,FeO 1.8%,and K_2O 7.92%.Its crystal form and thermal properties are very similar to those of mica-like clay minerals.According to isotopic age determinations of glauconite in mod- ern oceans (including the East China Sea,the South China Sea and the Yellow Sea),we consider that in the extreme case glauconite is an authigenic mineral.It is generally formed in sedimentary rocks.It has fur- ther proved that glauconite can be used to determine the ages of sedimentary rocks.

关 键 词：海绿石 地质年代学 沉积环境 晚白垩纪 原生代 结晶化学 矿物学 

分 类 号：P578.94[天文地球—矿物学]