Mantle plumes are areas of hot, upwelling mantle and hot spots develops above these plumes as noted in the map above. Magma generated by the hot spot rises through the rigid plates of the lithosphere and produces active volcanoes at the Earth's surface. As oceanic volcanoes move away from the hot spot, they cool and subside, producing islands, atolls, and seamounts. As the magma cools in the water it forms rocks