Research breaks ground with discovery of bacterial role in platinum nugget formation

23 Mar 2016
Platinum grain found in Brazil. Image courtesy of The University of Adelaide
Platinum grain found in Brazil. Image courtesy of The University of Adelaide.

Researchers have been instrumental in uncovering the key role of bacteria in the formation and movement of platinum and other related metals in surface environments.

Published this week in the journal Nature Geoscience, the research findings have important implications for the future exploration of platinum group metals.

Professor Gordon Southam said the discovery of nanoparticulate and microcrystalline platinum formed through bacterial processes has demonstrated that this precious metal is not inert and that an active biogeochemical weathering cycle exists for platinum.

“The capability of bacteria to transform precious metal grains into nanoparticulate materials has the potential to revolutionise the way we search for metal deposits,” he said.

“This research shows that novel exploration strategies for locating new metal deposits could be developed by targeting similar nanoparticulate materials in soils and sediments.”

Professor Southam said the formation of microscopic materials by bacteria may be critical for exploration in Australia where most of our bedrock is covered by highly weathered terrain.

Earth Science's Dr Carla Zammit is also part of the international research team, which is led by The University of Adelaide's Dr Frank Reith. Other collaborators include colleagues from The University of Western Australia, RMIT University, and the Federal Institute for Geosciences and Natural Resources in Germany.

Expansion of research

These latest findings are an expansion of Professor Southam and his team’s previous research on the formation of nanoparticulate gold from gold grains (Shuster et al., 2015) and on the accretion of secondary gold into new grains (Shuster & Southam, 2015).

Shuster, J., C.W. Johnston, N.A. Magarvey, R.A. Gordon, K. Barron, N.R. Banerjee and G. Southam. 2015. Structural and chemical characterization of placer gold grains: Implications for bacterial contributions to grain formation. Geomicrobiol. J. 32:158-169.

Shuster, J. and G. Southam. 2015. The in-vitro “growth” of gold grains. Geology 43:79-82.

Three dimensional, Backscattered Electron-Scanning Electron Microscopy (BSE-SEM) micrograph of a gold grain, panned from West Coast Creek, Queensland. (Image courtesy of Dr Jeremiah Shuster, The University of Queensland)
 
High magnification BSE-SEM micrograph of the gold grain above, demonstrating the occurrence of nanoparticulate and microcrystalline gold, which has ‘grown’ on the gold grain surface. Image courtesy of Dr Jeremiah Shuster
High magnification BSE-SEM micrograph of the gold grain above, demonstrating the occurrence of nanoparticulate and microcrystalline gold, which has ‘grown’ on the gold grain surface. Image courtesy of Dr Jeremiah Shuster
 

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