New date for largest iron deposits on Earth provides clues for future exploration

Research led by Curtin University reveals that the largest iron ore deposits on Earth – in Western Australia’s Hamersley Province – are about a billion years younger than previously believed, a discovery that could greatly boost the search for more many sources.

Using a new geochronological technique to accurately measure the age of iron oxide minerals, the researchers found that the Hamersley deposits formed between 1.4 and 1.1 billion years ago, rather than 2.2 billion years ago as previously estimated .

The main author Dr. Liam Courtney-Davies, who was a postdoctoral research associate at Curtin University’s John de Laeter Center at the time of the research and is now at the University of Colorado, Boulder, said the findings showed iron deposits formed during a period of high activity. geological time when ancient supercontinents were breaking up and new ones were forming.

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

“Discovering a link between these giant iron ore deposits and changes in supercontinent cycles increases our understanding of ancient geological processes and improves our ability to predict where we should explore in the future.

Study co-author Associate Professor Martin Danišík, from the John de Laeter Centre, said the research precisely dates minerals from banded iron formations (BIFs), which are ancient underwater layers of iron-rich rock that can provide insights important in the deep geology of the Earth. The past.

“Until now, the exact timing of these formations changing from 30% iron as they were originally, to more than 60% iron as they are today, has been unclear, which has hindered our understanding of the processes that led to the formation of the world. the largest ore deposits,” said Associate Professor Danišík.

“Using an emerging technique to date iron oxide minerals through uranium and lead isotope analysis within mineral grains, we have directly dated all of the major BIF-hosted iron ore deposits in the Hamersley Province.

“Our research shows that these deposits formed in association with major tectonic events, highlighting the dynamic nature of our planet’s history and the complexity of iron ore mineralization.”

Western Australia is the world’s leading producer of iron ore, which is Australia’s largest exporter at $131 billion last financial year. The research was done in collaboration with researchers from the University of Western Australia, Rio Tinto and CSIRO Mineral Resources.

The full study, titled “A billion-year shift in the formation of Earth’s largest ore deposits,” is published in Proceedings of the National Academy of Sciences.