World’s oldest gem leading us to hidden treasures

Zircon, the oldest mineral on the planet, is helping geologists understand how Earth started out and how it continues to evolve. By better understanding the Earth’s structure, mining companies have been able to find new mineral deposits.

The team sampling with Pan-African Mining geological team in Madagascar. Credit: Julia Galin
The team sampling with Pan-African Mining geological team in Madagascar. Credit: Julia Galin

“Most of the mineral deposits that are exposed on the surface of the planet have already been found and mined, but we need to find the ones that are still hidden,” Dr Elena Belousova says.

She and her colleagues at the ARC Centre of Excellence for Core to Crust Fluid Systems have developed TerraneChron®, a tool that looks at zircons found in geological samples, such as rocks or sand in river beds, to find out when they crystallised.

This determines how old the zircon is, and therefore how old the host rock is as well, helping define patterns in how Earth’s crust evolved.

TerraneChron® can also be used to find where many mineral deposits are, such as gold, nickel and diamond, and is now widely used by global mining giants including BHP Billiton, helping to guide strategies for exploration.

At 4.4 billion years old, some of these gems are almost as old as Earth itself. Zircon contains small amounts of radioactive elements such as uranium, making it an ideal tool for dating rocks. It has helped them look back over the last million years at how Earth’s crust and mantle have evolved.

“When Earth first formed, there was no continental crust, this just developed later on,” explains Elena.

“The structure of the Earth is always changing, and we want to better understand how it evolved. In the future this may help us analyse samples brought back from the Moon and Mars, and determine if the planets have formed and evolved in the same way.”

Elena is the recipient of the 2016 Australian Academy of Science’s Nancy Millis Medal for Women in Science.

For more information:
Elena Belousova
+61 2 9850 6126

Banner image credit: Will Powell