oldonyo1Ol doinyo Lengai (pronounced ol doyn-yo len-guy) is an active volcano in the Eastern Rift Valley, and it is home to the Masai God Eng’ai, who signals her wrath with eruptions and drought. The name means ‘Mountain of God’ in the language of the Masai people who inhabit this area. Ol doinyo Lengai is a unique and extremely fascinating volcano that towers above the East African Rift Valley in Northern Tanzania, just south of Lake Natron. It is located on the way between Ngorongoro Crater and the Serengeti and is part of many of our itineraries. Geologists are particularly interested in Ol doinyo Lengai because It is the only volcano in the world that erupts natrocarbonatite lava, a highly fluid lava that contains almost no silicon. Oldoinyo Lengai is also the only active volcano in this part of the Rift Valley, though there are many older extinct volcanoes in this region. The mountain rises a startling 2,886 m/9,469 ft above the parched Rift Valley floor.

Referred to as the strangest volcano on Earth, Ol doinyo Lengai earns its reputation when it erupts. oldonyo3Unusually cool, highly fluid lava produces a whimsical world of geologic fantasies that include extrusions frozen in flight. These natrocarbonatite flows have a chemical composition akin to laundry soap, and exposed to the atmosphere, the lava quickly hardens and decays. Unlike common basalt lavas, which are sticky with silica, Lengai’s lavas are mostly slick sodium carbonate with the viscosty of olive oil. Volcanic froth rich in carbon dioxide can spew into the air as liquid lava and harden in midair. Some of the big drops can form little parachutes, and look like silver flying through the air before hitting the ground with the sound of breaking glass. Lengai’s Dr. Seussian formations can crumble a day after they are born, and you can judge their age by their color. Even raindrops accelerate the decomposition