2018 年 83 巻 6 号 p. 509-520
Chemical compositions of rock-forming minerals in the pelitic rock, the siliceous rock, the felsic tuff, and the dolerite intrusions from the Onnagawa Formation in Ayukawa oil and gas field were compiled, based on their SEM-EDS analysis as basic data. They have been used for geochemical simulations to evaluate the precipitation and the dissolution of mineral in the water-rock interaction systems. The analyzed mineral groups were feldspar, zeolite, carbonate mineral and clay mineral. They seem to have relatively wide variation of their chemistry or to be important minerals in the simulation. This examination also revealed that the mineral described as talc in the former article (Okubo, et al.,1996) is pyrophyllite. Therefore its occurrence and chemical composition is also reported.