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DIAMOND ORIGINS

THE BIG BANG VERSUS THE SLOW GRIND

Where and how do diamonds originate in nature? The answer is relatively well known, and that is millions of years ago deep below the earth’s surface, where the temperatures and pressures are high enough that carbon matter would crystalize into the form we recognize as a diamond.

About this there is little argument, and indeed the process in nature has been replicated repeatedly in laboratories and factories. The method involved, HPHT, is today one of the two that is employed today to grow synthetic diamonds in a laboratory or factory.

But what initiated the sequence of events that led to diamonds being created, and from where did the carbon material originate? In other words, what was the “big bang” that led to the creation of the world’s most popular gemstone.

MOVEMENT OF SEVEN PLATES ABOVE EARTH’S MANTLE

Research indicates that it most probably was less of a big bang and more of a slow grind. Organic matter was essentially was drawn deep into the earth’s mantle through continental drift, which relates to movement of seven large plates above and below the earth’s surface, starting between 3 and 3.5 billion years ago. 

Plate tectonics theory suggest that the plates that glide over the earth’s mantle, the rocky inner layer above the core. The driving force behind plate tectonics is convection in the mantle. Hot material near the earth’s core rises, while colder mantle rock sinks. 

At subduction zones, two tectonic plates meet and one slides beneath the other back into the mantle, the layer underneath the crust. The sinking plate pulls the crust behind it downward.

This is not a fast process. Typical movement is about 10 millimeters to about 40 millimeters per year, which is about the rate at which fingernails grow.  A high rate of movement is 160 millimeters per year.

According to plate tectonics, where two tectonic plates meet below the surface of the ocean, one slides beneath the other back into the earth molten mantle. New research suggests that this may be the reason that many diamonds, which were created under conditions of extreme pressures and temperatures deep within the earth, originate from organic materials that came from the sea.

PLATE TECTONICS AND OTHER THEORIES REGARDING A DIAMOND’S ORIGINS

The association between diamond creation and tectonic plates has been discussed for more than 20 years, with geologist being aware that diamonds deposits are more likely to found in regions where the seven plates meet.

However, an article released on May 29 in the journal Science Advances, suggest that many diamonds have oceanic origin, making it likely that the organic material as well comes from the sea. The researchers looked at the salty sediment deposits inside fibrous diamonds. 

“There was a theory that the salts trapped inside diamonds came from marine seawater, but it couldn’t be tested,” said Michael Förster, a professor at Macquarie University in Australia, was the lead author in new study.

In their study, Förster and team showed evidence that when the old seabed slips into the mantle of the earth, the colliding forces create the perfect conditions for diamond formation. 

“We knew that some sort of salty fluid must be around while the diamonds are growing, and now we have confirmed that marine sediment fits the bill,” Förster said. 

But plate tectonics most probably account for but a portion of the diamonds created on earth. According to a recent study in published in the Nature journal suggest that certain diamond deposits are the results of neutron star collision 4.6 billion years ago, which resulted in diamonds raining down on our planets throughout the solar system. That must have been one big bang.

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