Dike:
But if magma travelled from [Mercury’s] core through its mantle, finally solidifying to form a crust on the surface, that could have stirred up the core. Usually, volcanoes are fuelled by many small veins of magma called dikes, but Mercury may have been cooled by melted rock flowing through larger tubes called heat pipes. [“Mercury may have shrunk because magma was being piped to the surface,” Leah Crane, NewScientist (3 April 2021)]
