Which volcano in Tanzania is the source of the black lava known as natrocarbonatite?

Ol Doinyo Lengai in Tanzania is the source of the unusual black lava known as natrocarbonatite. The volcano rises in the East African Rift and is regarded as the world’s only currently active volcano known to erupt carbonatite lava.

Natrocarbonatite is rich in sodium, potassium, and carbonate minerals and contains very little silica compared with ordinary silicate lavas. It erupts at relatively low temperatures, so it can appear black or dark gray when fresh. As it weathers, the lava commonly turns pale because its minerals react rapidly with moisture.

The volcano’s Maasai name is commonly translated as “Mountain of God.” Its summit contains active cones and a crater system, and eruptions can include lava flows, ash, and explosive activity.

Ol Doinyo Lengai should not be confused with Kilimanjaro, Tanzania’s famous snow-capped mountain. Kilimanjaro is a much larger volcanic massif, but it is not the source of natrocarbonatite lava and is not currently erupting.