Oldoinyo Lengai, Tanzania
U.S. Geological Survey photo (fair use policy)
Oldoinyo Lengai, in northern Tanzania, is the world's weirdest volcano. It erupts a unique sodium-carbonate lava whose temperature is so low that it comes out black, not red-hot. In the air's humidity, the solidified lava quickly gets a whitish powdery coating of sodium bicarbonate. We can explain the peculiar lava of Oldoinyo Lengai as a result of deep magma stuck beneath thick continental crust for a very long time. The East African Rift Valley recently opened and allows the topmost fraction of the long-simmering magma to vent as a carbonatite. For more, see my article about this mountain.
