Unlike the fiery red eruptions of traditional volcanoes, Ol Doinyo Lengai in Africa impressively erupts black lava.
For countless generations, the indigenous Maasai people in Tanzania (East Central Africa) have referred to this active volcano as Ol Doinyo Lengai, a term in their native language that means “Mountain of God.” According to Maasai mythology, the goddess Eng’ai, who is believed to have created the volcano, may have been in a foul mood during its formation.
The Maasai regard Eng’ai as the supreme deity who created all things. She is often depicted in two forms: a gentle and benevolent black form (Eng’ai Narok) and a red form (Eng’ai Nayokie) that is associated with disaster.
Ol Doinyo Lengai, the only active volcano in Tanzania. (Photo: ravpix/flickr)
Ol Doinyo Lengai is one of the most unusual volcanoes on Earth, and even in the solar system. From a distance, this mountain may seem unremarkable, but looking into its northern crater, observers will see an impressive eruption of unique black lava, which is relatively cool and flows like motor oil.
Located in the East African Rift, northern Tanzania, Ol Doinyo Lengai is the only known active volcano capable of erupting carbonatite lava, or natrocarbonatite lava. There is some evidence suggesting that volcanoes on Venus may have also erupted natrocarbonatite lava, but on Earth, Ol Doinyo Lengai remains the only active volcano of this type.
With a height of 2,962 meters, this volcano has two craters, but only the northern crater is active. The most recent eruptive period began in April 2017 and is still ongoing, according to the latest reports as of March 2024.
Ol Doinyo Lengai is the only active volcano known to erupt carbonatite lava.
In 2009, a team of volcanic researchers collected gas samples from Ol Doinyo Lengai to study its unique carbonatite lava. They discovered that the composition of these gases closely resembled those emitted from mid-ocean ridges, despite Ol Doinyo Lengai being located quite far inland.
This led the research team to conclude that the carbon-rich lava is produced by melting minerals in the upper mantle—the thick layer of rock just below the Earth’s crust. “The chemical properties and isotopic composition of the gases indicate that CO2 originates directly from the upper mantle, beneath the East African Rift,” stated David Hilton, a geochemist at the Scripps Institution of Oceanography at the University of California San Diego and co-author of the 2009 study.
| The East African Rift has been tectonically active for about 25 million years and remains one of the most fascinating geological hotspots in the world. This is a massive rift in the African plate that is slowly pulling apart at a rate of several millimeters each year. Over a long period, it may eventually split Africa in two, creating a new ocean between East Africa and the rest of the continent. In addition to Ol Doinyo Lengai, the East African Rift also contributes to the formation of many towering mountains in the region, such as Mount Kilimanjaro and Mount Kenya. |
Although there are a few other volcanoes that erupt carbonate lava, Ol Doinyo Lengai is unique in its own way. If you want to experience a truly extraordinary volcano, consider adding Ol Doinyo Lengai to your future travel destinations.
The carbon and silicate erupting from Ol Doinyo Lengai are black and have a temperature only half that of typical volcanoes. Nevertheless, it can still “burn” anything at temperatures over 500 degrees Celsius and then cool quickly upon exposure to air. At night, orange spots can also be seen rising from the crater, adding a colorful display to the otherwise black surface.
For many “volcanologists,” Ol Doinyo Lengai is likened to a “toy volcano” due to its moderate heat. Scientific teams frequently visit alongside tourists to study and admire the breathtaking landscapes created by nature. The lava resembles soap bubbles more than traditional magma, making it seem as if you could scoop it up with a spoon for a keepsake.
A Hornito resembling a giant horn standing atop the volcano. (Photo: Ric Lander/flickr)
Climbers and explorers often trek along the paths of the hornitos (spires formed by erupting lava). These conical rock formations fascinate many visitors, and getting close to the active volcano provides an even more thrilling experience.
Hornitos are formed with the help of large amounts of carbon dioxide. They create lava bubbles the size of soccer balls, and once they burst, they gradually form a base that builds up into a cone shape.
Each lava block erupted at Lengai is not very large, only about a meter wide, and it cools quickly while suspended in the air. Upon hitting the ground, it shatters almost instantly.
The black lava flow can easily be mistaken for mud. It is not difficult to determine the age of the lava erupted at Lengai. Initially, it has a pitch-black color, forming softly in waves known as pahoehoe. Depending on the internal composition, it may change to gray, brown, or black. After a few days, chemical changes occur when it rains, causing the lava surface to turn white and become more brittle.
From generation to generation, Maasai women gather at the foot of the volcano, hoping that the goddess Eng’ai will respond to their prayers and grant them children.
Many travelers choose Ol Doinyo Lengai not only to experience the heat beneath their feet that can melt their shoes but also because it is the only active volcano in Tanzania. This is not a typical tourist destination due to its geographical location in a wilderness area with no convenient accommodations like those found at Mount Kilimanjaro, Ngorongoro Crater, or Serengeti National Park.
From Arusha (420 km from the capital Dodoma), the nearest large town, it takes nearly a full day along dusty roads through Maasai lands and areas inhabited by ostriches, giraffes, and zebras to reach near Ol Doinyo Lengai. If you set off from the base camp around midnight (1 AM), you can reach the summit to watch the sunrise over the Rift Valley. Many travelers choose to camp overnight either in between or right at the foot of the mountain to avoid the long trek in one go.
Conical rock formations created by lava and gray lava flows down the slopes of Ol Doinyo Lengai. (Photo: Cw Anderson/flickr)
A striking feature that visitors can easily recognize from afar is the long flowing black lava, which presents a range of gray tones. Besides admiring this unusual volcano, you will also have the opportunity to meet the indigenous Maasai people and learn about their lifestyle and unique culture.
