Pillow Lava

An image of a dark seafloor hydrothermal vent with brown, bulbous pillow lava on top. The lava is surrounded by white clam-like creatures.
(NOAA Ocean Explorer)

The material that erupts at mid-ocean ridges cools into bulbous “pillow lavas.” These are located at the Galápagos Rift, where the Cocos Plate and the Nazca Plate move away from each other.