Gabbroic xenoliths and megacrysts in the Pleisto-Holocene alkali basalts from Jeju Island, South Korea: The implications for metasomatism of the lower continental crust

► The xenoliths are cumulus remnants related to the prior volcanism in Jeju Island. ► The xenoliths provide evidence for metasomatism of the lower continental crust. ► The volatile enriched metasomatic agent was related to the host alkali basalt. ► The metasomatization of the lower continental crust was a relatively young event.