藏王鉱山における硫黄鉱化作用と母岩の変質について

抄録

The sulphur deposits at the Zao mine are made up of a group of platy formed replacement bodies of sulphur and iron-sulphide ores, and are found in andesitic rocks of the Zao volcano.
Various kinds of altered rocks, such as sulphurized, pyritized, opalized, alunitized, kaolinized rocks and altered andesite, show zonal distribution around the high-grade ore bodies and the fractured zones. Chemically, the formation of these altered rocks is characterized by a leaching process. A large proportion of Ca, Mg, Fe and a small proportion of Al and silica have been removed from the original rocks without change in the apparent volume of the rocks. Only two components, S and H₂O, are found added in larger proportion from mineralizing fluid to the altered rocks.