Ol Doinyo Lengai: The Black Lava Volcano

Most people have seen something related to volcanoes ever in their lives; sometimes in documentaries, textbooks or even movies, ranging from a slight mention of a science project to one of those blockbusters focused exclusively on some mountain of magma about to erupt and kill thousands of people along the way.

And among so many options, it is extremely common for the following image to come to mind when we talk about this geological structure: incandescent lava, which it would be impossible to survive.

This is not wrong; most of them are just like that, and the expelled matter usually has a temperature around 1, 000 ° C. But Ol Doinyo Lengai is an exception to these rules.

1

Located in Tanzania, it is quite different from ordinary volcanoes, and all because of its chemical composition. The magmatic rock of most of these structures is basalt, while our dear black volcano is rich in carbonatite. And what's so different about?

Carbonatite has a much lower melting point than basalt; that is, it needs to heat up much less to melt, which makes it not glow. So your lava is black, not orange, as we are used to seeing - and it turns white when it hardens!

The fact that its melting point is smaller makes it much colder than the others. Remember that we commented that the temperature of the magma is usually close to 1, 000 ° C? Yeah, in the case of Lengai, it is around 510 ° C, just over half. Of course it is still very hot, but oddly enough it is possible to survive under these conditions. In 2008, a man on an expedition slipped and fell into the volcano. Sure, the pain was not at all easy, but he was rescued alive.

2

Despite being more than proven that it can survive at the temperature of the African mountain, a volcano is still a volcano, and this one has a plus that makes it even more dangerous, linked to this all special chemical composition. Ordinary lava is much thicker and heavier; It moves at a speed of 10 km / h, which is easy to overcome even on foot if you are running away from it (not to mention all the other factors that may be part of an eruption). In this case, the inverse is equally valid. If carbonatite is lighter, Lengai lava too can run as fast as water. So, as much as he seems more relaxed than the others, it is better not to fool.