[Rockhounds] Ol Doinyo Lengai Is The Weirdest Volcano On Earth, Maybe In The Solar System

[axel.emmermann at telenet.be]

Hi Kreigh and group,

Ol Doinyo Lengai IS indeed a special volcano. I mentioned it in one of my talks some years ago.
This volcano is situated in the great rift valley in Tanzania, near the border with Kenia.
The carbonatite lava that it produces is coming from the earth's mantle, instead of the deeper origins that produce silicic lava!
This mantle-lava has some peculiar properties. First of all, it is black but when it solidifies it turns white.
These white lava flows tend to be eroded away very quickly. The carbonatite rock is readily attacked by rainwater.
However, this lava has a quite high concentration of REE. These carbonatite lavas are exploitable! 
On the downside: Ol Doinyo Lengai is the only known volcano that produces this type of lava.

Cheers
Axel

 
Axel Emmermann 
Mineralogische Kring Antwerpen 
Mineralogical Society of Antwerp 
Werkgroep Fluorescerende mineralen 
Workgroup Fluorescent Minerals 
[ http://fluo.mineralogie.be/index.html | http://fluo.mineralogie.be/index.html ] 
Bezoek Minerant op 4 & 5 mei 2024

----- Oorspronkelijk bericht -----
Van: "Kreigh Tomaszewski" <kreigh at gmail.com>
Aan: "Rockhounds at drizzle.com" <rockhounds at rockhounds.drizzle.com>
Verzonden: Dinsdag 16 april 2024 03:25:07
Onderwerp: [Rockhounds] Ol Doinyo Lengai Is The Weirdest Volcano On Earth, Maybe In The Solar System

Ol Doinyo Lengai is one of the weirdest volcanoes on planet Earth, perhaps
even in the whole Solar System. While it appears typical enough from afar,
take a peek into its northern crater and you'll see it oozes with a unique
form of black lava that’s relatively cool and flows like runny motor oil.

Located in the East African Rift of northern Tanzania, Ol Doinyo Lengai is
the only active volcano known to gargle carbon-based lava, known as
natrocarbonatite lava. There's some evidence that volcanoes on Venus may
have once erupted natrocarbonatite lava too, but this African giant is the
only known producer on Earth (at least in relatively recent times).

Most volcanoes churn out lava rich in silicate minerals, making its melting
point over 900°C (1,652 degrees Fahrenheit). The lava of Ol Doinyo Lengai
contains relatively little silica, but has an abundance of carbonate
minerals, allowing the lava to enter a liquid state at just 540°C (1,004
degrees Fahrenheit).

The lack of silica makes the lava extremely viscous. When an eruption
occurs, it looks more like a spluttering pot of black motor oil than an
oozing trail of red-hot lava.

Given the viscosity of its lava, scientists are pretty surprised the
volcano can erupt so violently. Explosive eruptions often occur in other
volcanoes because gas bubbles can become trapped within the gloopy lava.
Nevertheless, it’s clear that Ol Doinyo Lengai can erupt with an intense
flurry of liquidy lava, perhaps because it's loaded with dissolved carbon
dioxide and other gases, making it effervescent like a fizzy soda.

https://www.iflscience.com/ol-doinyo-lengai-is-the-weirdest-volcano-on-earth-maybe-in-the-solar-system-73819
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