The Mid-Atlantic Ridge hosts numerous hydrothermal vent fields

The Mid-Atlantic Ridge hosts numerous hydrothermal vent fields. Logatchev, Rainbow, and Saldahna are underlain by variable mixtures of deeper crustal rocks (gabbro and peridotite) and both Logatchev and Rainbow host high-temp black smokers. The other fields are also black smokers but are hosted on volcanic rocks. Lost City is the only known field composed of carbonate chimneys.