The Ol Doinyo Lengai volcano in Africa is a unique geological wonder known for its unusual black lava that is rich in carbonate minerals. Unlike most volcanoes that erupt red-hot silicate lava, the lava from Ol Doinyo Lengai flows like motor oil and has a viscous texture. This makes it one of the most unique volcanoes on Earth.
The 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, this lava remains liquid at temperatures as low as 540 degrees Celsius due to its high carbonate mineral content. This makes it extremely viscous and gives it the appearance of spewing black motor oil during eruptions.
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. 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.
Overall, Ol Doinyo Lengai’s unique black lava flow provides a fascinating glimpse into how different types of magma can behave during an eruption and offers valuable insights into how geological processes shape our planet over time.