There is only one volcano in the world which is erupting carbonatite lava: Ol Doinyo Lengai in Tanzania. This is not just another dry fact for nerdy scientists: this volcano is very unusual place without analogues in the world.


The volcano is some 370 thousand years old and is the youngest volcano in this part of the East African Rift.

Of course, local people noticed this giant volcano which is rising tall above the dry plains south from Lake Natron. Here, in East African Rift are located many magnificent volcanoes – not too far are the magnificent Mount Meru and Ngorongoro Crater. But this volcano was very special to Maasai people – it was a sacred place named “Mountain of God” (Ol Doinoy Lengai).

This part of Africa was one of the last places reached by white people – first European visitors to Ol Doinyo Lengai were German explorers in the late 19th century.

The volcano is very active – every few years here takes place an eruption.

Ol Doinyo Lengai volcano, Tanzania
Ol Doinyo Lengai volcano / Richard Mortel, Flickr / CC BY 2.0

Thus, one of these eruptions in 1960 attracted the attention of Canadian geologist John Barry Dawson who was mapping this part of Tanzania. He and Ray Pickering descended in the crater of the volcano (this was the first known descent in the crater) in October 1960 and immediately noticed that this volcano is very unusual. Soon after, in 1962 he published the results of research – thus the first and only active carbonatite volcano on Earth was discovered.

Since then Ol Doinyo Lengai has been a “playground” for geologists exploring this unique natural wonder. Dawson himself continued the research until his decease in 2013.

Today volcano is rather a popular tourist attraction. Fittest visitors are ascending the mountain under the heat of the equatorial Sun and try to get closer to live volcanic activity. This is dangerous – this weird volcano is even less predictable than others and threats are looming in seemingly calm places.

Carbonatite lava

Nearly all volcanoes on Earth are spewing lava which consists of silicate minerals. Only some have been erupting lava which per more than 50% consists of carbonate minerals – carbonatite lava. We know some 20 locations of former carbonatite volcanoes but Ol Doinyo Lengai is the only one which is active now.

“Mountain of God” is erupting not just carbonatite lava – it is producing very specific, rare kind of it: natrocarbonatite lava. It consists of carbonate minerals – the very rare nyerereite (Na2Ca(CO3)2) and gregoryite (Na2,K2,Ca)CO3.

This material needs a considerably lower temperature for melting – this lava is flowing already at 500 – 600 °C temperature and in the daylight this lava is not even glowing – it is just a flow of a pitch-black stream. In the night lava glows in orange color. Usual lavas have a temperature of some 1100 °C.

Carbonatite lava is also quite fluid in comparison to common silicate lavas – it is the most fluid lava in the world flowing almost like water – often faster than a person can run. The flow of this lava looks like dark oil or brown, muddy foam.

Lava of Ol Doinyo Lengai volcano, Tanzania
Lava of Ol Doinyo Lengai volcano, Tanzania / Thomas Kraft, / CC BY-SA 3.0

Snow-white powder

As the lava hardens, it is pitch black, with glistering crystals in it. But it is not for long: these carbonatite lavas are quickly weathering. In a few hours time the stone turns white due to the moisture. If the weather is dry, lava turns white in a few days time. If the rain is raining – lava becomes white immediately.

This is caused by a chemical reaction similar to a reaction of burnt lime. Due to this both nyerereite and gregoryite are very rare minerals which even in geological collections should be kept in an argon atmosphere.

Over the time the white lava turns into a brown powder. After a few months, lava is soft – one sinks in it when walking.

Thus: the landscape of Ol Doinyo Lengai is unique, without analogs in the world.

Volcanic activity

Ol Doinyo Lengai is the only active volcano in Tanzania. It is very active and is erupting lava and ash every few years.

Hornito in Ol Doinyo Lengai crater, Tanzania
Hornito in Ol Doinyo Lengai crater / Thomas Kraft, Wikimedia Commons / CC BY-SA 3.0

Sometimes, when the content of silicates in lava increases, eruptions of volcano become explosive, sometimes starting with impressive lava fountains – such eruption took place in 2007 – 2008. Before these eruptions there happened many earthquakes – even lions left the area and it was also decided to evacuate also people and their cattle in a safe distance from the volcano.

During the eruptions in the crater often form hornitos – smaller hills and even towers, which emit the carbonatite lava. Lava sometimes forms short-lived lava lakes.

Since 1983 the lava has gradually filled the crater and now it is filled with carbonatites and it seems that this is endangering the stability of crater rims.

As the carbonatite lava spread over the surrounding plains, it has changed the soil. These grasslands are rich with succulents and serve as pasture for numerous wildebeest calves.

Ol Doinyo Lengai is included in the following articles and lists:

Lava lakes of the world
Lava lakes of the world in 2019
Lava lakes of the world in 2019 / Wondermondo / public domain
In October 2019 we have seven existing lava lakes on Earth. Three more existed for a longer time in the recent past. Besides this, since the year 2000 short-lived lava lakes and lava ponds existed in 11 more places. Wondermondo has listed them all in this article.

40 unique natural wonders of the world
Cave of the Crystals, Mexico
Cave of the Crystals / Alexander Van Driessche, Wikimedia Commons / free for use
40 unique natural wonders of the world[/caption] This article is a kind of wonder by itself: after meticulous work of several years here has been collected a list of absolutely unique places, where nature has outdone itself and created something unique, just in one example.


  1. Frederick Belton, Ol Doinyo Lengai, The Mountain of God . Accessed on June 26, 2017
Ol Doinyo Lengai on the map
Travelers' Map is loading...
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Location, GPS coordinates: 2.7596 S 35.9140 E
Categories: Volcanoes
Values: Geology, Visual
Rating: 4 out of 10 stars
Where is located? Africa, Tanzania, Arusha, some 19 km south from Lake Natron
Alternate names: Oldoinyo Lengai
Name in Maasai: Ol Doinyo Lengai (The Mountain of God)
Height: 2,890 – 3,188 m (according to diverse sources)

Landmarks of Tanzania

Palace of Sultan in Zanzibar Stone Town
Palace of Sultan in Zanzibar Stone Town / Vincent van Zeijst, Wikimedia Commons / CC BY 3.0

This very diverse country has unforgettable scenery and many world famous landmarks. Highlights of Tanzania are its unique ecosystems, early human finds and historical trading towns at the Indian Ocean.


Mount Cleveland, Aleut Islands
Mount Cleveland / NOAA Photo Library, / CC BY 2.0

This category includes the most unusual and interesting volcanoes of the world.

Over the last 10,000 years in some 1,500 places around the Earth through the crust of the planet has been emitted lava, ash and gases from the mantle of Earth. Each of these places could be considered to be an active volcano. Every year some 50 – 70 volcanoes are erupting, at any moment there are some 20 – 30 eruptions on-going.

Recommended books

Volcanoes of the World

This impressive scientific resource presents up-to-date information on ten thousand years of volcanic activity on Earth. In the decade and a half since the previous edition was published new studies have refined assessments of the ages of many volcanoes, and several thousand new eruptions have been documented.

Geology of National Parks of Central/Southern Kenya and Northern Tanzania

This book describes the interrelationship between the spectacular geology of an area of East Africa that includes a branch of the rift valley, as well as giant freestanding ice-capped mountains and extraordinarily toxic, alkaline lakes, and some of the greatest concentrations of wildlife on Earth. It suggests that geological processes that have shaped the iconic landforms, including active volcanoes, may also be responsible for the unusually diverse speciation which characterises the region.

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