A group of researchers from MIT have uncovered the mystery of the "cratonic roots" anomaly, due to which the speed and graph of the passage of acoustic signals through certain areas of the rock were severely distorted. We are talking about seismic waves that shake the bowels of the planet and have been closely studied for more than a dozen years. The reason probably lies in the myriad deposits of wealth in the depths of our Earth.
Craton is an ancient stable area of the earth's surface, the core of the continent, which for a long time, from a billion years or more, was not subjected to destructive tectonic activity. The craton has a kind of "roots" - rocky outcrops the size of a mountain, directed downward towards the center of the Earth. The substances of which they are composed are very strong and solid, which is confirmed by a change in the speed of passage of oscillatory waves through them.
However, in some cases, the velocity of the wave passing through specific craton roots is several times higher than the calculated one. Scientists simulated the conditions and found that in order to achieve this effect, there must be many inclusions of a substance with the strength of diamond inside the rock. From 1% to 2% - taking into account the dimensions of the cratons themselves, this is the largest deposit of precious stones in history. The account goes not to billions of tons, but to quadrillions!
Alas and ah, the depth of the craton roots starts from 150 km and deeper, therefore, with existing technologies, it is unrealistic to reach them. Yes, and not profitable - with such a quantity, diamonds will immediately cease to be a rarity and will lose value. But this gives food for thought and material for experiments, because then many geological postulates need to be revised.