摘要
绝大多数海绿石是自生矿物,在通常情况下,基本上可以获得与其共生的沉积岩时代,当海绿石年龄与所在地层时代不相符时,只要深入进行矿物学、岩石学及地质背景研究,就有可能得到比较合理的解释。
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 glau-conite has a mica-type structure between dioctahedron and trioctahedron. Its chemical com-position is: Al2O310.67%,SiO249.23,MgO3.24%,FeO17.40%,FeO1.8%, and KO7.92%. Its crystal form and thermal properties are very similar to those of mica-like clay minerals. According to isotopic age determinations of glauconite in 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. It has further proved that glauconite can be used to determine age of sedimentary rocks.
出处
《地球化学》
CAS
1988年第4期343-350,共8页
Geochimica
