Research carried out by scientists at Keele University, the University of Manchester and University College Dublin has shed new light on how precious metals - over ten times rarer than gold - are concentrated in igneous rocks.
The solidified remains of sub-volcanic magmatic intrusions host the greatest concentrations of platinum-group metals in the Earth’s crust, such as platinum, palladium and rhodium. Scientists refer to these bodies as layered mafic intrusions. Traditional models suggest that these layered intrusions form in large volume magma chambers, but this new research has found that it’s more likely small amounts of magma is repeatedly injected into a crystal mush.
The research, published in Nature Geoscience and led by Dr Brian O'Driscoll from the University of Manchester and co-investigated by Dr Ralf Gertisser from Keele University's School of Geography, Geology and the Environment, former PhD student Dr Luke Hepworth, and Professor Stephen Daly from University College Dublin, demonstrates the case for re-evaluation of the long-held belief about how layered mafic intrusions are formed.
The research involved carrying out a detailed study on an approximately 60 million year old extinct volcano on the island of Rum in northwest Scotland. Mineral crystals in the Rum intrusion were analysed using a novel microsampling approach, to identify isotopic variations of the element strontium.
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