Magma evolution of Slamet Volcano, Central Java, Indonesia based on lava characteristic

Abstract

We reported magma evolution of Slamet volcano, both temporally and spatially, as represented by its lava characteristics. Slamet volcano, located in Central Java Indonesia, is a Quaternary basaltic stratovolcano and part of the extensive Sunda volcanic arc. Slamet volcanism stage can be divided into Old Slamet and Young Slamet. Old Slamet characterized by basaltic to andesite (SiO2 49-59%), composition and have rough morphology in the western flank. Meanwhile, Young Slamet has more mafic composition, basaltic to basaltic andesite (SiO2 48-52%), and smoother morphology in the eastern flank. Variation of major, minor, and trace element combined with petrographic features suggest that the differentiation process of Slamet magma is dominantly caused by fractional crystallization and magma mixing. Detailed temporal evolution suggested that magma of each Old Slamet and Young Slamet undergo a differentiation process that changes magma composition from mafic to more felsic for several times. Old Slamet evolved more intensive, producing a wide range of silica content and might coincide with some explosive events in the past. Young Slamet which the youngest stage represented by Guci unit is dominated by mafic magma. Differences between Old and Young Slamet lead to the conclusion that they come from a different magma chamber.