R6: Plutonic rocks, volcanic rocks and subduction factory

[R6P-06] Petrography and whole-rock geochemical compositions of mafic rocks occurring in the Kajishima, Shisaka Islands, Ehime Prefecture

[Presentation award entry]

*Kazuya Shimooka¹, Satoshi Saito¹ (1. Ehime Uni., Sci.)

Keywords:Gabbro, Cretaceous, Kajishima, Southwest Japan

In this study, we describe petrographic characteristics and newly acquire whole-rock geochemical compositions of mafic rocks in the Kajishima, Ehime prefecture. The mafic rocks can be divided into troctolite, gabbro, gabbronorite, and mafic dyke based on field observation and petrography. They show whole-rock SiO2 contents of 43-50 wt % which are in the range of that of mafic rocks (SiO2 = 41-66 wt %) associated with Cretaceous granitoid batholith in southwest Japan.