There is only one volcano in the world which is erupting carbonatite lava: Ol Doinyo Lengai in Tanzania. This is not just another dry fact for nerdy scientists: this volcano is very unusual place without analogues in the world.Ol Doinyo Lengai, "Mountain of God" in the Maasai language, is an active volcano located in the Gregory Rift, south of Lake Natron within the Arusha Region of Tanzania. Part of the volcanic system of the East African Rift.