Abstract:

This paper deals with the characteristics, homogenization temperature, volatile constituents and chemical compositions of the glass and daughter minerals of the melt inclusions in diopside and plagioclase from Tertiary volcanic rocks in this area. The homogenization temperature of melt inclusions in the diopside ranges from 1070 to 1170℃. Many melt inclusions in plagioclases have homogenization temperature 1100℃ The composition of the gas bubbles from melt inclusions in diopsides and plagio clases are 45-93% CO2, a few to 35% H2S, 2-20% CH4, 2-14% CO, and small amounts of N2, H2, O2 and H2O. These compositions vary regularly from early to late stages of volcanic eruption. The compositions of glass and daughter minerals in diopside have been analysed and kirschsteteinite is the main daughter mineral.