A groundbreaking study led by Curtin University has uncovered that the Earth’s largest iron ore deposits, located in Western Australia’s Hamersley Province, are approximately one billion years younger than previously believed.

This discovery could significantly enhance the search for additional iron ore resources.

Using an innovative geochronology technique to accurately measure the age of iron oxide minerals, researchers determined that the Hamersley deposits formed between 1.4 and 1.1 billion years ago, rather than the previously estimated 2.2 billion years.

Dr Liam Courtney-Davies, the lead author of the study, explained that the findings reveal a connection between iron deposit formation and major geological activity during the breakup and formation of ancient supercontinents.

“The energy from this epic geological activity likely triggered the production of billions of tonnes of iron-rich rock across the Pilbara,” Dr Courtney-Davies stated.

Associate Professor Martin Danišík, a co-author of the study, highlighted the importance of precisely dating minerals from banded iron formations (BIFs).

These ancient underwater layers of iron-rich rock provide valuable insights into Earth’s geological past.

The research team employed an emerging technique to date iron oxide minerals through uranium and lead isotope analysis within mineral grains, allowing them to directly date all major giant BIF-hosted iron ore deposits in the Hamersley Province.

The study’s findings indicate that these deposits formed in conjunction with major tectonic events, emphasising the dynamic nature of our planet’s history and the complexity of iron ore mineralisation.

This new understanding of the link between giant iron ore deposits and supercontinent cycles could improve the ability to predict potential exploration sites in the future.

Western Australia, the world’s leading producer of iron ore, relies heavily on this resource, which contributed $131 billion to Australia’s export earnings in the last financial year.

The research, conducted in collaboration with The University of Western Australia, Rio Tinto, and CSIRO Mineral Resources, will be published in the Proceedings of the National Academy of Sciences journal under the title A Billion-Year Shift in the Formation of Earth’s Largest Ore Deposits.