The new finding, detailed online in the journal Nature Communications, suggests the gems could probably be found on every continent, even Antarctica.
Diamonds form under the intense heat and pressure found nearly 100 miles below the Earth’s surface, in the mantle layer, which is between the outer crust and the core. Powerful volcanic eruptions drive diamonds to Earth’s surface, where they are embedded in blueish rocks known as kimberlites.
Kimberlites can range from 10,000 to 2.1 billion years in age, and can have the deepest sources of any rocks on Earth’s surface.
Until now, kimberlites were found on every continent except Antarctica. Now, scientists have discovered these rocks on the southernmost continent.
Diamonds on every continent
Researchers analyzed geological samples from boulders on the southeastern slopes of Mount Meredith, part of the huge Prince Charles mountain range in East Antarctica. The scientists found three kimberlite samples to be about 120 million years old; they formed around the time when the area that is now India was drifting away from the combined landmass of Australia and Antarctica.
The kimberlites lie near the margins of the Lambert rift, an enormous, transcontinental rift that crosses much of Antarctica.
The age of the Antarctic kimberlites and their chemical, mineral and physical properties suggest they are part of a huge Cretaceous kimberlite province. This vast region is responsible for many of the world’s diamonds, and is now spread across most of the continents that were once part of the super continent Gondwanaland.
No diamond mines in Antarctica
Only about 1 to 2 percent of kimberlites contain valuable grades of diamond, and of these, most are much, much less than 1 carat of diamond per ton of kimberlite.
Establishing the viability kimberlite deposits as a possible diamond mine requires processing several tons of kimberlite to establish its grade, and this is clearly difficult at best in the Antarctic environment. Additionally, mining activity is prohibited in Antarctica under the Madrid Protocol, to which 50 nations are signatories. So, this discovery will not lead to a diamond-mining industry in the southern continent, and this is how it should be in my opinion.
Incidentally, although diamonds are often thought of as nature’s hardest material, it turns out two other rare natural substances are harder: wurtzite boron nitride, which is formed during intense volcanic eruptions, and lonsdaleite, which is sometimes created when meteorites hit Earth.