Ol Doinyo Lengai stratovolcano in the Gregory Rift of Arusha, Tanzania is strangely, still one of the last active volcanoes in the African continent producing unique deposits, natrocarbonatite lava.
Derived from a Maasai word, Ol Doinyo Lengai, means “the mountain of God”. This stratovolcano cuts through East Africa’s Rift Valley towering at 2000m with a summit elevation of 2890m.
What’s unique about the carbonatite lava flow from the Ol Doinyo Lengai is its rich nature in sodium and potassium carbonites – very rare – as well as gregoryite and nyerereite deposits which make it appear shiny black in the sun due to the low temperatures in the mountains. In other cases, lava flow appears red hot.
At night though, it is extremely fluid and black in colour but turns into a powder white once it cools down or when raining.
Ol Doinyo Lengai’s carbonatite ash which spreads to the surrounding areas greatly influences the annual wildebeest migration from Maasai Mara in Kenya into the Serengeti in Tanzania. The ash enriches the soil and pasture blossoms, making it a harbour for feeding, giving birth and calving for the wildebeest from October onwards.
Ol Doinyo Lengai is one of the few carbonatite volcanoes in the world and Homa Mountain spreading to Kenya’s Western and Nyanza regions is a product of old and extinct carbonatite lava deposits. Carbonatite is an extrusive igneous rock with half of its composition made up of carbonate minerals.
In 2007, there was volcanic activity in the mountain which caused a 6-day tremor in Tanzania and Kenya. Months later, the volcano erupted, a process which continued into 2008.
The lava flow resulted in a small lava lake which was captured in 2010 in an aerial view and natrocarbonatite flow resumed in 2013, filling the crater formed by the 2007-08 eruption. It is, however, not accessible to climbers.
For mountain climbers temperature go as high as 40 degrees celsius, hence climbs are mostly organized after midnight to reach the summit in the sunrise. The views at the summit are impressive, on the north Lake Natron is visible, the westside view give you the Great Rift Valley, and the eastern part offers majestic views of Mount Kilimanjaro.