No matter how you view them, the fact is that diamonds are merely rocks that are billions of years old that have been subject to crushing pressures and hot temperatures. Another version of this activity is how our Earth is compressing its oceans into salty diamonds.
In any event, we know that it takes a very long time for a hunk of carbon to become crystallized into a beautiful sparkling diamond. And the fact is that scientists really aren’t entirely clear how they are made. One theory that has gained recent popularity is that lots of our diamonds are formed when the oceanic plates continue to grind on the continental plates at the alleged tectonic subduction zones.
Oceanic Plates Provide the Pressure
During this process, oceanic plates and the minerals on the ocean floor eventually penetrate hundreds of miles into the mantle of the Earth. It is there where they gradually crystallize under extremely high pressures and temperatures that are tens of thousands of times higher than at the surface. Over time, all of these crystals blend with the volcanic magma that is known as kimberlite and together they eventually burst onto the surface of the planet as beautiful diamonds.
The biggest reason for this ocean diamond theory is due to the fact that oceanic minerals give us blue stones — such as the infamous Hope diamond.
These diamonds are the rarest, deepest and by far the most expensive on the planet, which make them very difficult to study and observe. This research has been recently published in the publication Science Advances and features evidence for oceanic origins of diamonds. During this study, scientists examined the salty sediment deposits within a very common type of stone, which are referred to as fibrous diamonds.
Fibrous Diamonds Provide Lots of Data
Unlike the diamonds that wind up in weddings, these fibrous diamonds are actually clouded with tiny deposits of potassium, salt, as well as other substances. They are much less valuable to a jeweler, but they are incredibly valuable to researchers who are seeking to reveal their underground origins.
“There was a theory that the salts trapped inside diamonds came from marine seawater, but it couldn’t be tested,” said Michael Förster, who is a professor from Macquarie University which is located in Australia and also the lead author of this study.
Thus, Förster and his associates attempted to create inside their lab the conditions that this diamond undergoes whenever minerals on the seafloor minerals subduct into the mantle of the Earth. The research team inserted marine sediment into containers along with a mineral known as peridotite, which is a type of volcanic rock that widely exists at depths where diamonds are believed to form. They then exposed this mixture to very intense pressure and heat conditions to mimic what would take place at the mantle.
The research team learn that whenever the mixture was exposed to pressures of 4-6 gigapascals and temperatures of 1,500 to 2,000 degrees Fahrenheit, salt crystals began to form with almost identical characteristics as the ones that exist within fibrous diamonds. Therefore, whenever the seabed seeps down into the deeper regions of the mantle, the various forces produce the perfect condition for formation of diamonds.
“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 stated. He also pointed out that their experiments created minerals that are vital to formation of kimberlite, the material that future diamonds hitch a ride on to the surface of the Earth during a volcanic eruption.
