Geodigest

Abstract

New research into the forces that bring diamonds to the surface from deep in the Earth’s mantle could help locate undiscovered diamond deposits, say Macqurie University geologists (Fran Molloy, Physorg, 27 July 2023). In a new study, Emeritus Professors Suzanne O’Reilly and Bill Griffin (Fig. 1) worked with a team led by Tom Gernon at the University of Southampton in the UK to track the past billion years of patterns of continent formation and tectonic plate movement. Linking these patterns with known deposits of diamondrich kimberlite rocks, they found the breakup of tectonic plates is the main driving force behind the generation and eruption of diamondrich magmas from deep inside the Earth. Australia’s mineral exploration has already found most of the worldclass and large mineral deposits visible at the surface, in the onethird of the continent not buried under hundreds of metres of dirt and young sediments, says Professor O’Reilly. The twothirds of Australia with deep sediment cover should contain the same proportion of worldclass mineral deposits as the visible regions, she says— but traditional discovery methods will not work to find these minerals vital for a sustainable future. For example, it is estimated that by 2030, the global demand for cobalt used in renewable energy batteries will be around 50 times what it was in 2016. Unless we can become selfsufficient in this strategic metal, Australia may be held to ransom with huge price increases and chronic shortages, says O’Reilly. Their work in understanding the deep processes that create economic mineral deposits has helped the researchers develop a new predictive strategy to find minerals called the GLAM approach (Global Lithospheric Architecture Mapping)— developed with industry collaboration. This has revolutionized the way mineral exploration is now done by progressive industry explorers, says Professor Griffin. The new research has demonstrated this technique, showing how tracing the unique process of diamond formation can help geologists locate previously unknown diamond deposits. Jewellery makes up a fraction of the world’s diamond trade; most diamonds are used in industrial applications they are valued as the hardest natural