East African Rift’s Ol Doinyo Lengai: A Unique Volcano with Carbonate Lava and Geological Implications

Ol Doinyo Lengai, a volcano located in northern Tanzania on the East African Rift, is one of the most unique volcanoes on Earth. Unlike most volcanoes that erupt red-hot silicate lava, Ol Doinyo Lengai spews black lava rich in carbonate minerals. This makes it a fascinating geological wonder for scientists and researchers alike.

Unlike most volcanoes, Ol Doinyo Lengai’s lava is viscous and flows like motor oil. Its black color is due to its high carbonate mineral content, which makes it extremely difficult to cool down. Despite its low silicate content, the lava remains liquid at temperatures as low as 540 degrees Celsius due to its high carbonate mineral content.

Ol Doinyo Lengai has two vents, but only the northern vent erupts. The most recent eruption began in April 2017 and was ongoing as of March 2024. During these eruptions, the lava can still erupt violently, producing streams of liquid lava filled with dissolved CO2 and other gases that bubble like carbonated water.

A team of volcanologists studying gas samples from the volcano in 2009 found that the composition of the gases was similar to those spewed from mid-ocean ridges, suggesting that the carbon-based lava is produced by minerals melting in the upper mantle. This discovery has led to further research into the formation of this unique type of volcanic rock.

Located on the tectonically active East African Rift, Ol Doinyo Lengai is just one of many geological wonders in the region. This giant crack in the African plate is slowly moving apart and could eventually tear Africa in half, creating a new ocean. In addition to Ol Doinyo Lengai, the East African Rift is responsible for creating other towering mountains in the region, such as Mount Kilimanjaro and Mount Kenya.