R6: Plutonic rocks, volcanic rocks and subduction factory

[R6-06] Andesitic melt obtained from the melting experiments of mantle peridotite

*Nobutaka Tsuchiya¹, Daisuke Yamazaki² (1. Iwate Univ., 2. Okayama Univ.)

Keywords:experimental petrology, andesite

The partial melting of depleted peridotite plus slab melt at 1.5 GPa was studied for H2O saturated conditions. The quenched glasses obtained at 1000oC are dacitic in composition, having 67–68 wt% SiO2. On the other hand, the quenched glasses obtained at 1050oC are andesitic in composition, 61–64 wt% SiO2. This suggests that calk-alkaline dacites to andesites can be generated by the reaction of slab melts with mantle peridotite. Moreover, this suggests that calk-alkaline andesites can be formed by direct partial melting of the hydrous upper mantle contaminated with slab melts.