Rare rocks buried deep beneath central Australia have revealed the origins of one of the world's most promising new deposits of niobium - a metal vital for producing high-strength steel and clean energy technologies - and how it formed during the breakup of an ancient supercontinent.
The Curtin University-led study found the newly discovered niobium-rich carbonatites were emplaced more than 800 million years ago, rising from deep within the Earth through pre-existing fault zones during a tectonic rifting event that ultimately tore apart the supercontinent Rodinia.
Lead author Dr Maximilian Dröllner, from the Timescales of Mineral Systems Group within Curtin's Frontier Institute for Geoscience Solutions and the University of Göttingen, said the findings shed new light on how rare, metal-rich magmas reach the surface - and why this particular deposit is so interesting.
"These carbonatites are unlike anything previously known in the region and contain important concentrations of niobium, a strategic metal used to make lighter, stronger steel for aircraft, pipelines and EVs and a key component in some next-generation battery and superconducting technologies," Dr Dröllner said.
"Using multiple isotope-dating techniques on drill core samples, we found that these carbonatites were emplaced between 830 and 820 million years ago, during a period of continental rifting that preceded the breakup of Rodinia.
"This tectonic setting allowed carbonatite magma to rise through fault zones that had remained open and active for hundreds of millions of years, delivering metal-rich melts from deep in the mantle up into the crust."
Curtin co-author Professor Chris Kirkland, also from the Timescales of Mineral Systems Group, said the research shows how using advanced geochronology and isotope techniques can unravel such complex histories.
"Carbonatites are rare igneous rocks known to host major global deposits of critical metals such as niobium and rare earth elements. But determining when and how they formed has historically been difficult due to their complex geological histories," Professor Kirkland said.
"By analysing isotopes and using high-resolution imaging, we were able to reconstruct more than 500 million years of geological events that these rocks experienced.
"This approach allowed us to pinpoint when the carbonatites formed and separate those original magmatic events from changes that happened later in the rocks."
The full study, titled 'Multi-method geochronology and isotope geochemistry of carbonatites in the Aileron Province, central Australia', was published in 'Geological Magazine'. (doi.org/10.1017/S0016756825100204)
