R6: Plutonic rocks, volcanic rocks and subduction factory

[R6-03] Magmatic processes and geographical features of Abu and Aonoyama volcano groups, Yamaguchi Prefecture

*Masaaki Owada¹, Haruka Imachi, Mariko Nagashima¹ (1. Yamagucni Univ. Sci.)

Keywords:Abu/Aonoyama volcano groups, alkali-basalt, adakite, magmatic process, volcanic landform

Quaternary andesite to dacite of the Abu and Aonoyama volcano groups, Yamaguchi Prefecture, shows distinct geographical features. The andesite to dacite of the Abu group occurs as a plateau, whereas that of the Aonoyama group shows a domal structure. Consequently, the andesite to dacite magmas of Abu volcano group were solidified as lava plateaus because the magmas would be of low-viscosity conditions due to enrichment of alkali contents and high-temperature.