広島県安芸郡音戸町の花崗岩中にある青緑色粘土細脈

概要

論文の詳細を見る
The constituent minerals of the pale-green vein (ca. 6 m in the vertical direction) in the granitic rock of the Ondo-cho district, Hiroshima Prefecture, as well as those in its surrounding rock, has been examined by X-ray powder diffraction, DTA, optical and electron microscopical observations and EPMA. The clay vein consists mainly of quartz, montmorillonite and the interstratified mineral of illite/swelling-layer (illite : 0.8-0.1, swelling-layer : 0.2-0.1) . The montmorillonite exists dominantly in the upper part and shows a distinct tendency to decrease towards the lower part, the other way the interstratified mineral tend to increase. The interstratified minerals are divided into two types in both chemical composition (Fe_2O_3 : 16%, 2.5%) and morphology (the elongated tabular habit, the irregular plate) are comparable with those of mica group. Comparing chemical composition of the interstratified mineral with that of montmorillonite, the amount of Al_2O_3 in the latter is less than that in the former. In the granitic rock surrounding the lower level of the clay vein, plagioclase grains are almost completely replaced by illite, and biotite grains are completely replaced by chlorite, while potash feldsper grains are only scarcely replaced by secondary mineral (Fe-rich minerals) along their grain boundaries.
日本粘土学会の論文
1978-03-25