Dear Jaime Leonardo: The Juina (Mato Grosso) diamond crystal containing a microinclusion of azure-blue ringwoodite is certainly of deep mantle origin. This mineral is stable at depths below some 430 km in the mantle, as hyperbaric experiments have shown. Microdiamonds have been found in some meteorites, but I think this one is too large to belong to a shocked meteorite, and was released into alluvial sediments through the erosion of a kimberlite pipe or similar volcanic body. So the Juina diamond ringwoodite microinclusion is probably the only natural sample found on Earth of this high-pressure polymorph of olivine, with spinel structure, and it is also somewhat hydrated, as the chemical analysis have shown. In some articles this discovery was regarded as "there is an ocean in the interior of the Earth", but obviously that is not the case. There's a small proportion of (OH), that is protonized oxygen, in the ringwoodite found, which is not free or molecular water, but combined water, such as that: 2(OH)- = O2- + H2O, this dehydration reaction only can take place a very high temperatures. Surely, the ringwoodite rich shell in the mantle (from 430 to 670 km depth) contains the equivalent of water of at least the actual world oceans, but it is not an "underground ocean of water" as the Lindenbrook Sea in Jules Verne "Voyage to the Center of the Earth". Regards and obrigado! Sebastian.

Sebastian

This comment to me is the way of

"it seems that".

This video may suggest some other positions

The largest lunar basin: Internal effects

http://www.lpi.usra.edu/exploration/training/resources/impact_cratering/SPApressure

for more:

http://www.lpi.usra.edu/exploration/training/resources/impact_cratering/

For that, understand

That point is not asking me !!!

If a lithospheric mantle with diamonds -Proton or Archon type Juina lithspheric mantle,

Would have been affected by the impact of a mega meteorite,

What would happen?

Consider that an impact crater on the moon produces craters 6 times larger than that produced by the same impactor in the earth:

2400 Km-D on the Moon would be 2400/6 on Earth.

If you look at most of the publications you will see drawings of a plate in subduction beyond the lithospheric cratonic mantle, penetrating even beyond the 600 Km of depth.

Is there seismic evidence (f / ex. Seismic tomography) about that in Juina?

Mostly they are only designs, the paper supports everything ..... it says nothing!

So I have the right to doubt,

With more reason why apparently in the neighborhood of Juina there would be a mega crater of impact (possibly impact basin).

I said only doubt,

I do not say, I'm only interested in opinions

And his position is very well received.

Dear Jaime: if we enter the field of speculation, then anything can happen and it is possible! As far as I know, there's no evidence of such megaimpact crater in the Mato Grosso region of Brazil. This doesn't mean that an impact of such couldn't have happened in that vast region in the past, of course. But ancient impacts are very hard to identify, even more so in a swampy-selvatic region such as Mato Grosso, or the Amazonia itself. Surely the Brazillian Shield is a stable area, old enough as to have been impacted several times by all sorts of meteorites or asteroids, just as happened in the Canadian or the Australian Shields, but there's no evidence of such impacts. Moreover, I find difficult to explain an inclusion of ringwoodite inside a shocked, relatively surficial mantle diamond. If the diamond was a product of an impact on a crustal rock containing carbonaceous matter or graphite, how could it have contained an inclusion of olivine at the same time? Just imagine how improbable would be that a graphitic mass would contain a tiny crystal of olivine inside and that the whole assemblage was shocked by an asteroidal impact, so that the graphite turned to diamond, and the olivine to ringwoodite. Far out and hard to believe! Both substances, graphite and olivine, are not associated or compatible in a rockand th only way that the Juina diamond could have formed by an impact would have been if they were together in the same grain! That's why the best explanation is that the Juina diamond is a superdeep diamond containing an inclusion of ringwoodite of mantle origin, formed at least at a depth of 430 km, where such high pressure polymorph is stable. Other diamonds in the world, including one found in the Guaniamo kimberlites in Southern Venezuela, have rare inclusions of Fe-periclase, another deep mantle phase, even deeper in origin than ringwoodite, as Fe-periclase generates from the high-pressure breakdown of ringwoodite itself a depths below 670 km, which forms Fe-periclase and and very high pressure polymorph of enstatite called bridgmanite! As if there is any evidence of seismic tomography in Southern Brazil I have no idea! Regards, Sebastián.  

Sebastian creo que es mejor decirlo en español:

imagina un manto con diamantes que es afectado por un mega-impacto,

como lo sugiere el vídeo.

No digo son diamantes formados por impacto,

digo diamantes de la litosfera Proton o Archon tipo el área de Juina, y si fueron afectadas por un mega impacto?

Cordial saludo