Origin of olivine-clinopyroxene cumulates inferred from the Takashima xenolith suite, northern Kyushu

Abstract

Dunites and olivine-clinopyroxenites can be formed by simple crystal cumulation from melts, but wehrlites cannot be formed by the same way. The olivine-clinopyroxene rocks from the Takashima xenolith suite show gradual modal variations from dunite to clinopyroxenite. They show recrystallization textures formed at subsolidus conditions, leading to change of Mg# of olivine and clinopyroxene. The igneous Mg#s of olivine and clinopyroxene are recalculated. The mineral chemistry indicates that the order of formation is dunites through clinopyroxenites to wehrlites. We will discuss the formation process.