Liquid Impurities in Diamonds Prove to be Valuable for Geological Study

Jun, 2021 - By SMI

Understanding the inclusions in diamonds can provide information about their age and also uncover Earth's history.

Geologists from Columbia University analyzed fluids trapped in tiny pockets inside diamonds for having better understanding of the age of humanity's favorite gem. In this study, published in the Nature Communications journal, they found three distinct diamond formation periods in Africa ranging over a couple of billion years ago, along with implications for the planet’s history that are intriguing.

From geological perspectives, the so-prized, gem-quality diamonds in the jewelry market are worthless. Since, they must be in their purest form, without any sort of trapped “inclusions” of varied elements. However, those inclusions for the geologists are of massive interest. Analysis of these impurities could provide scientists with plenty of information about how old the diamond is, including the conditions and environment that aided its formation.

Hence, for the latest study, researchers from Columbia University explored liquid inclusions, which may provide a more accurate timespan. After all, carbon-rich fluid is present in little pockets from which originally the diamond formed. The three different periods for formation of diamonds were separated by drastically distinct chemical compositions. The earliest one ranging back nearly 2.6 billion to 700 million years ago, having carbonite mineral rich inclusions.

The next time frame was back to 550 million to 300 million years, having high silica minerals in the inclusions. Lastly, in the third period, framed from 130 million to 85 million years ago, the composition showed high saline compounds of potassium and sodium within the inclusions. This, according to the team, indicates the carbon source shift, since the diamonds were being formed increasingly from seafloor portions pulled deep into Earth.

 

The researchers express that through this study not just the understanding of formation of diamonds can be improved, but distinct periods in Earth's history itself.