Ol Doinyo Lengai, “Mountain of God” in the Maasai language, is an active volcano located in the Gregory Rift, Northern Tanzania. Part of the volcanic system of the East African Rift. Ol Doinyo Lengai is unique among active volcanoes in that it produces natrocarbonatite lava, a unique occurrence of volcanic carbonatite.
Whereas most lavas are rich in silicate minerals, the lava of Ol Doinyo Lengai is a carbonatite. It is rich in the rare Sodium and Potassium carbonates. Due to this unusual composition, the lava erupts at relatively low temperatures of approximately 510 °C (950 °F). This temperature is so low that the molten lava appears black in sunlight, rather than having the red glow common to most lava. It is also much more fluid than silicate lavas, often less viscous than water. The sodium and potassium carbonate minerals of the lavas erupted at Ol Doinyo Lengai are unstable at the Earth’s surface and susceptible to rapid weathering, quickly turning from black to grey in colour. The resulting volcanic landscape is different from any other in the world.
The record of eruptions on the mountain dates from 1883 to recently in 2013