Despite their incredible reputation as exceptionally rare and valuable, diamonds are more common than you might think. Other planets, like Uranus, are probably full of them. They are floating around on some space rock right now. As it turns out, we Earthlings may be sitting on a diamond nut – actually a quadrillion tons.
Over 100 miles below the Earth's surface is a section of geology known as the Cratonic Roots. They sit beneath what geologists call a kraton, the oldest and most stable part of the continent's rock. Some reach deep into the earth – capable of stretching up to 200 miles deep through the outer crust and into the Earth's mantle ̵
"Cratons are closely associated with some of the most important events in Earth's history, such as the initiation of plate tectonics and the formation of continents," says Joshua Garber, a postdoctoral fellow at Penn State University and the lead author of the new study. "They have been stable since the Archean Aeon, at least 2.5 billion years ago, so they had plenty of time to make a lot of things happen … they have long been chemically defeated in this cloak." The results will result in a greater effort to understand the history and processes in the superficial and deep mantle regions of the earth.
In a recent work published in Geochemistry, Geophysics, Geosystems this week, an international research team estimates that about 1 to 2 percent of the Earth's kratonic roots are diamond. That may seem like a small amount, but this tiny fraction makes enough of these formidable geological formations to account for one quadrillion tons of diamonds. This is the number 1 followed by 15 zeros !
The research team did not look for shiny gems in this discovery. For years scientists have collected a tremendous amount of earth seismic activity data. This data can be used to create a kind of three-dimensional map that depicts the interior of the earth.
But not all seismic data add up evenly. Much of this is done with sound wave measurements that emanate from Earth after being triggered by earthquakes, explosions, and other events. These sound waves (also called shear rates or friction speeds) move at different speeds depending on the nature and temperature of the material moving through them, and thus move faster through the roots of ancient cratons because they are colder and less dense the surrounding cladding cladding. But the shear rates accelerate at higher than expected speeds due to kratom roots.
"Such high shear rates would be expected if temperatures at this depth are much colder than average," says Barbara Romanowicz, co-author of the new seismology research study at the University of California, Berkeley. "But you would have unrealistically low temperatures compared to what we know about these regions of the mantle for standard rock compositions."
The team wanted to know what would be responsible for the unusually fast speed measurements. They began their investigation with the data they had to create a 3D model of the seismic waves beating through the kratom roots, followed by laboratory studies of sonic waves heated by various combinations of soil minerals to temperature profiles found in the kratom roots. 19659002] Cratons consist predominantly of peridotite, but can not show high shear rates. There were only two other minerals that exist in the Earth's mantle that could explain the velocities: Eklogite (subducted oceanic crust descending into the mantle zone) and Diamond
They would require an unrealistic amount of eclogite to allow for the observed shear rates , In the meantime, "Diamond has extremely fast shear rates, so you only need a little bit of it, especially when combined with Eklogit to compare the observations," says Romanowicz.
The Only Rock Structures in Laboratory Tests That Explain This The rates observed in nature only had a pinch of diamonds – 1 to 2 percent. This was enough to compensate for the discrepancies in the sound wave data without affecting the total measured densities of the kraton roots.
While the results are a little unexpected, they make a lot of sense (though maybe not a quadrillion tons sense). "Diamond is a really attractive answer because it's so much stiffer than most other minerals," says Garber. "One result of this study is that if the answer is not diamond, there is a little bit more of another stiff component besides diamond, for which we have even less evidence."
In addition, Romanowicz says it is possible. Kratondiamonds could be derived from carbonaceous fluids rising from subducted plates (diamonds are essentially stable forms of carbon that are created by extremely high temperatures and pressures).
But do not get too excited: you'll never see those pretty rocks in your flesh. Again, they are over 100 miles underground – "about 10 times deeper than the deepest hole ever drilled in a continent," says Romanowicz. "Drills are consumed very quickly and soften when they reach high temperatures of several hundred degrees Celsius, and cooling by water injection is not enough to make up for that, and I honestly do not think that will happen in the foreseeable future."  "On the other hand," she continues, "diamonds come to the surface, carried by ancient volcanism, and perhaps there is more out there already found," given what the results suggest, "so there is there may be hope. "We may just have to be patient, but when it comes to geological time, that kind of patience must go beyond our species (19659002) Besides, would you really want that? If there were a quadrant of diamonds passed around the earth, those gems would suddenly not be as valuable as they do. Diamonds would probably be as valuable as a copper penny. (Although Lincoln's face was etched on the face of a diamond, that would be a brilliant change anyway.)