Science

Quadrillion tons of diamond discovered deep within the Earth

Quadrillion tons of diamond di...
 new study suggests there may be 1,000 times more diamonds in the Earth's interior than previously believed
 new study suggests there may be 1,000 times more diamonds in the Earth's interior than previously believed
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 new study suggests there may be 1,000 times more diamonds in the Earth's interior than previously believed
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 new study suggests there may be 1,000 times more diamonds in the Earth's interior than previously believed

In case you weren't already sure that diamonds aren't as unique or valuable as advertisers want us to believe, the next blow to Big Diamond might have just arrived. Using sound waves, geologists have discovered a gigantic stash of the so-called precious stones deep in the Earth's interior, possibly to the tune of a quadrillion tons.

The study began when an international team of researchers set out to solve a long-standing geological mystery. Scientists can infer what kinds of rock makes up different parts of the planet by studying seismic activity. Basically, the sound waves created as the result of earthquakes or volcanic rumblings will travel at different speeds through different types of rock, painting a picture of what's down there.

But one area doesn't behave like it would be expected to. Cratons are the oldest and most immovable slabs of rock on (or rather in) Earth, with roots stretching down from the center of the tectonic plates to a depth of up to 200 mi (320 km). The assumed makeup of these pillars would produce faster sound waves, but not to the speeds that have been observed.

"The velocities that are measured are faster than what we think we can reproduce with reasonable assumptions about what is there," says Ulrich Faul, an author of the study. "Then we have to say, 'There is a problem.' That's how this project started."

To figure out what the cratonic roots could be made of, the team studied seismic data gathered by the US Geological Survey and other organizations to create a 3D model of how these waves propagate through cratons. Then, they simulated sound waves moving through a wide range of different combinations of rock types to find one that matches the observed velocities.

In the end, only one particular rocky recipe produced the same sound wave speeds. Cratons would need a diamond content of about one to two percent, with the rest made up of peridotite and small amounts of eclogite.

That might not sound like very much diamond, but given the entire volume of cratons on Earth, the team estimates there could be up to a quadrillion tons of the stuff down there – about 1,000 times more diamond than was previously known.

"This shows that diamond is not perhaps this exotic mineral, but on the [geological] scale of things, it's relatively common," says Faul. "We can't get at them, but still, there is much more diamond there than we have ever thought before."

The find is just the latest trove of inaccessible diamonds that show the gems aren't all that rare after all. They've been found in meteorites from long-lost worlds, raining down on Neptune, floating in clouds around distant stars, and may even make up entire planets.

The research was published in the journal Geochemistry, Geophysics, Geosystems.

Source: MIT

12 comments
Bob Stuart
Diamonds have also ground away the other pebbles on a beach in Namibia. DeBeers won't let anyone but archaeologists near it.
Knut
Diamonds are produced in many places, not at the MIT. But the oil industry "consume" diamonds by using them on the drill-heads going into the rocks. But this kind of use in not explored in the US, you have to come to Europe for that. Diamonds have been produced for years, so the amount is not finite and never was believed to be finite.
MarylandUSA
The earth weighs 6.4 quadrillion tons. This discover means that diamonds could comprise almost 15 percent of the planet's mass.
Venetian
This is very bad news for the DeBeers monopolists who continue to use slave labor to mine diamonds, and will as per usual do their best to suppress this news and deflect from what it actually means. The illusion that sparkly rocks are desirable and "precious" must be maintained.
BrianK56
There goes the price of diamonds.
PB
This is old news. We've known that diamonds are swimming around in the core of the planet, just looking for a way out. What the article doesn't say is that the heat of the extrusion cooks most diamonds - the extrusion must be dramatic and rapid so that the heat is expelled rapidly, and there hasn't been such an extrusion in thirty million years. There are numerous diamond sources around the planet, but the cost of extraction is, generally, uneconomic. It takes a kimberlite which is high grade to provide the economic return, and this reduces sources of gem grade diamonds to a few dozen. In the USA there are diamondiferous kimberlites in Kentucky and Colorado, but are of low grade and concentration and are uneconomic.
bwana4swahili
Ha, but we already knew this from the movie The Core. Science following up on science fiction, again!
CraigAllenCorson
Knut, you are mistaken in two respects. First, in your statement that diamond drills are not in use in the US. They are, in fact, quite commonly used in all sorts of drilling/boring operations. Second, in your use of the word "finite". You seem to think that it means "limitless", but that is the exact opposite of what it means. Finite = limited, bounded. Infinite = UNlimited, boundless.
chinamike
This quote: "We can't get at them, but still, there is much more diamond there than we have ever thought before." Pretty much sums it all up. Firstly anyone who thinks that buying diamonds in one of millions of jewelry stores is investing in something worthy--I got some swamp land in Florida I would like to see you. The diamonds that are set in jewelry in retail stores are about as priceless and the thick green-glass bottom of a Coca Cola bottle. Diamonds are absolutely worth ZERO dollars. The only ones that are priceless, or worth anything are ones that only someone with a 7 figure balance in their bank can afford. Gold on the other hand is valuable and can be easily traded in the event of an emergency. All the gold ever discovered, mined and so on would only fill an Olympic sized swimming pool. That means any and all gold from recorded history.
JoeBelkin
Buyng diamonds have always been a scam (and as engagements, DeBeers sold the story but it's really ony in the past 90 years with the ad campaigns starting in the 20s ... just as until the oast 10 years, hardly anyone in China bought diamonds as engagement/wedding rings - gold/latnium is rare - diamonds are just polished rocks - and as noted, can be manufacturered from a charcoal briquet under pressure.