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This special mineral that humans use to profess their love for one another? It may not be so special. A new study suggests that the interior of the Earth is filled with a quadrillion tonnes of diamonds.
A new study published in June in the journal Geochemistry, Geophysics, Geosystems suggests that there are 1000 times more diamonds below the surface of the Earth than before.
But these diamonds are inaccessible: they are located about 90 to 150 miles (145 to 240 kilometers) below the surface of the Earth in the "roots" of the cratons, which are large sections of rock. The cratons are found under most continental tectonic plates and have barely moved since ancient times, according to a statement from MIT News. [Photos: The World’s Weirdest Geological Formations]
A group of researchers from various universities around the world discovered the glitzy hiding by looking at the seismic waves beneath the Earth. Because these vibrations may change depending on the composition, temperature, and density of the different rocks that they reach, researchers can use these recordings to construct an image of the inaccessible interior of the Earth.
They found that underground vibrations natural processes such as earthquakes and tsunamis tend to accelerate when they cross cratonic roots; the acceleration was greater than one would expect from the fact that the cratons tend to be colder and less dense than the surrounding structures (both being conditions that would accelerate the waves).
Using registers of seismic activity maintained by government agencies such as the US Geological Survey, the team created a three-dimensional model of seismic wave velocities that traveled through major cratons of the planet. Then they created "virtual rocks" from various combinations of different minerals and calculated how quickly the seismic waves would travel through these rock compositions.
They found the best explanation of the speeds actually observed underground compared to those predicted was that 1 to 2% of the roots of the cratons were made of diamonds, the rest being composed of peridotite (the main type of rock in the upper mantle). of the Earth) and a few eclogitic rocks (oceanic crust) When the 'waves cross the Earth, the diamonds transmit them faster than other rocks or minerals that are less steep', said Joshua Garber, a postdoctoral student at UC Santa Barbara and senior author of the study
. "We found that most of the data was better explained by diamond … we can not say for sure," Garber said. Since it is difficult to directly sample these regions (but not impossible, since sometimes parts of these cratonic roots are brought to the surface by the erupting magma), it is the best explanation for the region. present time, said Garber
. alternative explanations: Perhaps, these cratonic rocks are colder than what the literature suggests, which means that the rock will be stiffer – and therefore, seismic waves will travel faster through them – even without the diamond stones or d & # 39; eclogite. However, according to his data, he thinks that this last scenario is less likely.
"Our understanding of the deep Earth continues to improve as we do more measurements, do more experiments, and sometimes get samples." "I think we will continue to be surprised by what we find."
Originally published on Live Science .
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