The Ol Doinyo Lengai volcano in Africa is a unique and fascinating geological wonder known for its unusual black lava that is rich in carbonate minerals. Unlike most volcanoes that erupt red-hot silicate lava, Ol Doinyo Lengai’s lava is black, viscous, and flows like motor oil. This makes it one of the most unique volcanoes on Earth.
This volcano is located in northern Tanzania on the East African Rift and is the only known volcano to erupt carbon-based lava known as natrocarbonatite lava. Despite its relatively low silicate content, Ol Doinyo Lengai’s lava remains liquid at temperatures as low as 540 degrees Celsius due to its high carbonate mineral content. This makes the lava extremely viscous and gives it the appearance of spewing black motor oil during eruptions.
However, despite its appearance, the lava can still erupt violently, producing streams of liquid lava filled with dissolved CO2 and other gases that bubble like carbonated water. The most recent eruption began in April 2017 and was ongoing as of March 2024. 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.
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.