Abstract
Kusatsu Shirane volcanois is one of the Quaternary active volcanos located in back arc side of northeast Honsyu arc. Many studies have been conducted in a lot of fields, such as geology, petrology, geodesy and geothermal research. However, the generation and evolution processes of magma for the most primary stage of the activity of this volcano are not clarified enough. In this study, I focused on the Matsuozawa volcanic products which were formed in most early stage of activity of Kusatsu Shirane volcano and tried to investigate their processes of magma generation and evolution through field investigations, petrographical observations and chemical analysis of minerals by electron probe micro analyzer (EPMA).
