Sound waves have revealed giant diamond deposits deep beneath the earth’s surface
According to a new study by scientists from MIT and other institutions, there are more than a trillion tons of diamonds deep beneath the Earth’s surface. According to estimates, the precious minerals lie at a depth of more than 160 kilometers – far deeper than man has ever reached.
Scientists from the Massachusetts Institute of Technology (MIT), along with colleagues from China, France, Germany and the UK, have determined through the use of sound waves that there is more than a billiard of tons of diamond beneath the surface of the earthow. A publication on the subject appeared in the journal „Geochemistry, Geophysics, Geosystems”.
Billion (1,000,000,000,000,000,000) tons of diamondow. Such an amount could disappoint manyocic in the head. Unfortunately, mankind will not reach for them soon. This is due to the depth at which theorej the precious minerals are found. Drilling down to a depth of 160 kilometersow currently exceeds our capabilities.
Researchers have determined that the diamonds are found in the oldest, hardened part of the Earth’s crust – kraton. Shaped like a reverseocone gory, cratons can reach depths as deep as 320 kilometersow. The deepest sections of the cratonow geologists refer to as roots. Scientists estimate that it is these cratonic roots that may contain 1 to 2 percent diamond. Given their total volume, the compositeoł estimated the mass of the scattered diamondsow for a billion tons.
– Our research shows that diamonds on the geological scale are relatively common. Admittedly, we can’t even get close to it, but it’s still much more of a diamondow than ever thought – said Ulrich Faul of MIT.
The research was sparked by a certain anomaly in the seismic data. For several decades rosundry institutions around the world (such as the USGS – United States Geological Survey) keep records of seismic activity. The research monitors sound waves traveling through the Earth caused by quakes, explosions and other spectacular events.
Seismic receivers around the world collect sound waves from such sourcesodeł. Seismologists can use them to determine at least where an earthquake occurred.
But sound waves can row also be used to construct a picture of what the Earth’s interior might look like. The sound waves move with ro¿ with different speeds through the Earth, depending on the temperature, density and composition of the rocks, through which theyore podroThey feed.
Scientists have used this relationship between seismic velocity and rock composition to estimate the types of rocks that make up the Earth’s crust and some of the gor different mantle – lithosphere. Using seismic data to map the Earth’s interior, scientists have been unable to explain a strange anomaly: sound waves tend to accelerate significantly as they pass through the roots of the craton’sow. It is known that cratons are colder and less dense than the surrounding mantle, which in turn produces slightly faster sound waves, but not as fast as the measurements indicated.
– The measured velocities are faster than what we think can be reproduced under reasonable assumptions. We knew that here was the problem. This is how the project began – recalled Faul.
The team aimed to determine the composition of cratonic roots, ktore could explain spikes in seismic velocities. Seismologists first applied seismic data from the USGS and other sources ofode³ to generate troA three-dimensional model of the velocity of seismic waves traveling through the mainowne cratons of the Earth. Subsequently, Faul, along with the researchers, ktoers in the lab in the past have measured the speed of sound through many roThe study was initiated by a certain anomaly in the seismic data, which does not carry changes in the density of cratonsoin mineralow, they used this knowledge to assemble virtual rocks made of roThe mineral’s various combinationsow.
Teamoł calculated how fast the sound waves would travel through each virtual stone and discovered only one type of rock, ktora produced the same velocities as measured by the seismologistow. This is the kind of rock thatory oprocz peridotite – the dominant rock type goof the Earth’s mantle – and small amounts of eclogite, contains 1 to 2 percent diamondow.
– Diamond is unique in many ways. One of its special properties is that the speed of sound in diamonds is more than twice as fast as in the dominant mineral in gorm mantle of the Earth – peridotite – explained Faul.
The rock composition developed in the computer model of 1 to 2 percent diamond would be enough to produce higher sound speeds, and it fits the measurement perfectlyow seismologistow. This small admixture of diamondsow does not carry changes in the density of cratonow, whichore, as already mentioned, are less dense than the surrounding Earth’s mantle.
– Diamonds are like pieces of wood floating on water. The cratons are slightly less dense than the surrounding rocks, so they do not dip deeper and thus preserve the oldest rocks in them. We discovered that it takes only 1 to 2 percent diamond to make cratons stable and not sink – explained Faul.
The researchers’ findings are confirmed by the current state of knowledge of the diamagneticow. They are formed in the Earth’s interior, in an environment where there is tremendous pressure and high temperatures. They come to the surface through volcanic eruptions. These in turn produced something like geological chimneysow of kimberlite. This type of rock is named after the town of Kimberley in South Africa, where the first diamonds were found in these rocks.
In most casesow kimberlite chimneys have been found at the cratonic edges of the Earth’s sourceosources, such as in someorych parts of Canada, Siberia, Australia and South Africa. – This is a proofod circumstantial, but we put it together. We have gone through all the possibilities, we have investigated this case from every angle, and this is the only reasonable explanation – emphasized Faul.