Lava from Tanzania’s mysterious Ol Doinyo Lengai volcano could reveal Earth’s secrets, according to a report in the publication New Scientist, citing Kate Laxton from University College London who has been studying the volcano for several years.
One of the unique features of Ol Doinyo Lengai is that it produces effusive eruptions of natrocarbonatite, but every now and then also explodes with a silicate lava – a switch, Laxton says, which is not well understood by scientists.
The natrocarbonatite lava has lower viscosity, which in turn makes it one of the fastest flowing lavas and it could easily be mistaken for oil or dirty water. Another unique feature of Ol Doinyo Lengai is that its natrocarbonatite lava is black because it erupts at low temperatures – anywhere between 400 and 600 degrees centigrade – much lower than standard lavas which are rich in silicate and erupt anywhere between 700 and 1,200 degrees centigrade.
According to Laxton, the lava samples collected at Ol Doinyo Lengai may contain clues to Earth’s underworld. In particular, chemical signatures can reveal where in the mantle the ingredients for this strange magma come from and how they were “cooked up” in the first place.
“Essentially what we think happens is that there is a silicate magma reservoir somewhere below the volcano and then natrocarbonatite separates out from that – a bit like oil and water – at some depth within that plumbing system. So the natrocarbonatite inherently comes from a silicate parent,” UCL’s Laxton said.