Boffins at Curtin University have published new research they believe proves the Pilbara’s massive Hamersley iron ore deposits are one billion years younger than previously estimated.
By using a new and emerging technique to measure the age of earth materials, researchers have been able to get a more accurate picture of how far back the iron oxide minerals of WA’s rich deposits go.
And in a substantial leap from a previously estimated 2.2 billion years, the new research out of Curtin’s John de Laeter research centre suggests the Hamersley deposits were in fact formed between 1.4 and 1.1 billion years ago.
Liam Courtney-Davies, who was the lead author on A Billion-Year Shift in the Formation of Earth’s Largest Ore Deposits, said having a better understanding of ancient geological processes would be beneficial for future exploration.
“The discovery of a link between these giant iron ore deposits and changes in supercontinent cycles enhances our understanding of ancient geological processes and improves our ability to predict where we should explore in the future,” Dr Courtney-Davies said.
Findings from the research effort showed the iron deposits were formed during a period of “major geological activity when ancient supercontinents were breaking apart and new ones were forming,” he said.
His study co-author Associate Professor Martin Danišík said the timeline of these formations changing from 30 per cent iron to more than 60 per cent iron today, had been unclear until the research was completed.
“By using an emerging technique to date iron oxide minerals through uranium and lead isotope analysis within the mineral grains, we directly dated all the major giant BIF-hosted (banded iron formations) iron ore deposits in the Hamersley Province,” he said.
“Our research indicates these deposits formed in conjunction with major tectonic events, highlighting the dynamic nature of our planet’s history and the complexity of iron ore mineralisation.”
The University of Western Australia, CSIRO and Rio Tinto — the British-Australian mining giant that owns five mines in the Hamersley iron ore region — were collaborators on the research.