Davemaoite-Mineral From The Earth's Lower Mantle

[Min Bannister]

A mineral has been discovered in a diamond which has come from the Earth's lower mantle. Normally such minerals don't survive as they need extreme pressure to hold their form but this one has survived as it is encased within a diamond. It is thought to have been formed somewhere between 660 and 900km below the Earth's surface. This is only the second high pressure silicate mineral to have been discovered - the other is called Bridgemanite and was found inside a meterorite. The Independent link is here but you need to register so I have also posted the MSN link.

https://www.independent.co.uk/news/science/davemaoite-interior-earth-mineral-mantle-b1958475.html

https://www.msn.com/en-gb/news/worl...houldn-e2-80-99t-be-there-e2-80-99/ar-AAQLrAF

Davemaoite, the scientists say, is a calcium silicate compound, CaSiOâ-perovskite that showed up as infinitesimal small dark specks in a diamond unearthed in the 1980s.

It arrived on the surface decades ago in Botswana via the Orapa mine — the world’s largest diamond mine by area.

A gem dealer later sold the diamond in 1987 to a mineralogist at the California Institute of Technology in Pasadena.

Dr Tschauner and his team then got their hands on the diamond, and analysed its interior structure using a new suite of scientific tools.

They named the new mineral “davemaoite” after Ho-kwang “Dave” Mao, a geophysicist who developed many of the techniques that Dr Tschauner and his team use today.

This is the coolest thing I have read for ages.

 

[Min Bannister]

Here is a link to the announcement from the Carnegie Institute.

https://epl.carnegiescience.edu/new...l-discovery-named-after-trailblazing-carnegie

"Groundbreaking discovery" hurhurhur!

 

[Kondoru]

Its pretty awe inspiring, isn't it?

 

[Frideswide]

Its pretty awe inspiring, isn't it?

This! Excellent find and post @Min Bannister

 

[Sid]

Here is a link to the announcement from the Carnegie Institute.

https://epl.carnegiescience.edu/new...l-discovery-named-after-trailblazing-carnegie

"Groundbreaking discovery" hurhurhur!

I don't know the answer to this (my) question. . . does everything inside the inner earth, eventually rise to the surface of the earth, as shown, or does it rise up to the surface only from the upper mantle?

 

[kesavaross]

I don't know the answer to this (my) question. . . does everything inside the inner earth, eventually rise to the surface of the earth, as shown, or does it rise up to the surface only from the upper mantle?

I was thinking about that as well. How do they know it came from the earths lower mantle?

 

[Min Bannister]

I don't know the answer to this (my) question. . . does everything inside the inner earth, eventually rise to the surface of the earth, as shown, or does it rise up to the surface only from the upper mantle?

The Carnegie link shows an illustration where the diamond pipe actually starts in the lower mantle. So I suppose the diamonds are pushed up towards the surface and in this case a diamond managed to have this mineral as an inclusion.

I was thinking about that as well. How do they know it came from the earths lower mantle?

I wonder if Geologists are able to predict lower mantle minerals in a similar way to how chemists can predict undiscovered elements?

@Sharon Hill are you able to elaborate on this subject?

 

[EnolaGaia]

I was thinking about that as well. How do they know it came from the earths lower mantle?

As far as is known this particular mineral's crystal structure can originate and be maintained under conditions that can't happen naturally at the earth's surface or only so deep as the planet's crust.

Davemaoite has been artificially synthesized in the laboratory, but was thought to be too extreme to exist in the Earth's crust. ...

Calcium silicate is found in other forms, such as wollastonite in the crust and breyite in the middle and lower regions of the mantle. However, this version can exist only at very high pressure of around 200,000 times that found at Earth’s surface.

https://en.wikipedia.org/wiki/Davemaoite

 

[Sharon Hill]

The Carnegie link shows an illustration where the diamond pipe actually starts in the lower mantle. So I suppose the diamonds are pushed up towards the surface and in this case a diamond managed to have this mineral as an inclusion.


I wonder if Geologists are able to predict lower mantle minerals in a similar way to how chemists can predict undiscovered elements?

@Sharon Hill are you able to elaborate on this subject?

Mineralogy isn't my wheelhouse but I think they can postulate to a degree what might exist as was done with Davemaoite. A primary area of understanding in geology is the concept of "facies" where you can discern the environment of the rock based on the minerals it contains. Many minerals aren't static as they change composition or crystal structure based on the environmental conditions they are under. Example: Carbon as diamond under intense heat and pressure, or a mineral can oxidize to become something else.

 

[Sid]

The Carnegie link shows an illustration where the diamond pipe actually starts in the lower mantle. So I suppose the diamonds are pushed up towards the surface and in this case a diamond managed to have this mineral as an inclusion.


I wonder if Geologists are able to predict lower mantle minerals in a similar way to how chemists can predict undiscovered elements?

@Sharon Hill are you able to elaborate on this subject?

A bit more info on 'Davemaoite,' and yes - I believe I've answered my own question (#7 as above).
See ~ https://www.sciencenews.org/article/mineral-diamond-davemaoite-earth-mantle-heat

 

[kesavaross]

As far as is known this particular mineral's crystal structure can originate and be maintained under conditions that can't happen naturally at the earth's surface or only so deep as the planet's crust.


https://en.wikipedia.org/wiki/Davemaoite

Thanks. I just read that. interesting.

I still don't know how they can know something came from 400+ miles down from the surface. It might have come from 20 or 30 miles or it may occur in circumstances they are not yet knowledgable about. I'm just curious about having knowledge without direct experience or observation.

It's something I'm going to read up on as it seems an interesting subject matter.

 

[Sharon Hill]

Thanks. I just read that. interesting.

I still don't know how they can know something came from 400+ miles down from the surface. It might have come from 20 or 30 miles or it may occur in circumstances they are not yet knowledgable about. I'm just curious about having knowledge without direct experience or observation.

It's something I'm going to read up on as it seems an interesting subject matter.

It's physics. You can calculate temperature and pressure. You can test how minerals react to that. Crystal structure collapses and reorganizes under particular conditions.

 

[kesavaross]

It's physics. You can calculate temperature and pressure. You can test how minerals react to that. Crystal structure collapses and reorganizes under particular conditions.

I'm not disagreeing with you. Far from it. How do they know what the temperature and pressure is 400+ miles down? No one has been there to measure it.

I've emailed a friend of mine who is a geologist to recommend some books.

 

[Min Bannister]

I'm not disagreeing with you. Far from it. How do they know what the temperature and pressure is 400+ miles down? No one has been there to measure it.

I've emailed a friend of mine who is a geologist to recommend some books.

Although it seems totally off the wall to you and me, people will have been modelling and calculating this stuff since Hutton. And as Sharon notes, Physics has rules so it is possible. Of course if we ever do go down there and it turns out to be James Mason being chased by giant lizards after all then I'll be the first to admit I'm wrong.

 

[gordonrutter]

Although it seems totally off the wall to you and me, people will have been modelling and calculating this stuff since Hutton. And as Sharon notes, Physics has rules so it is possible. Of course if we ever do go down there and it turns out to be James Mason being chased by giant lizards after all then I'll be the first to admit I'm wrong.

Whilst geology is cool let's be honest it would be way cooler if it was James Mason and giant lizards!