Australian researchers reporting in the journal Nature Communications have detected particles of gold in the branches and leaves of eucalyptus trees growing in the Kalgoorlie region of Western Australia.
Lead author Dr Melvyn Lintern from CSIRO Earth Science and Resource Engineering with co-authors used CSIRO’s Maia detector for x-ray elemental imaging at the Australian Synchrotron to locate and see the gold in the leaves. The instrument produced images depicting the gold, which would otherwise have been untraceable.
“The eucalypt acts as a hydraulic pump – its roots extend tens of meters into the ground and draw up water containing the gold. As the gold is likely to be toxic to the plant, it’s moved to the leaves and branches where it can be released or shed to the ground,” Dr Lintern explained.
The discovery is unlikely to start an old-time gold rush – the nuggets are about one-fifth the diameter of a human hair.
However, it could provide a golden opportunity for mineral exploration, as the leaves or soil underneath the trees could indicate gold ore deposits buried up to tens of meters underground and under sediments that are up to 60 million years old.
“The leaves could be used in combination with other tools as a more cost effective and environmentally friendly exploration technique,” Dr Lintern said.
“By sampling and analyzing vegetation for traces of minerals, we may get an idea of what’s happening below the surface without the need to drill. It’s a more targeted way of searching for minerals that reduces costs and impact on the environment.
“Eucalyptus trees are so common that this technique could be widely applied across Australia. It could also be used to find other metals such as zinc and copper.”
“Our advanced x-ray imaging enabled the researchers to examine the leaves and produce clear images of the traces of gold and other metals, nestled within their structure,” said study senior author Dr David Paterson from the Australian Synchrotron.
Bibliographic information: Melvyn Lintern et al. 2013. Natural gold particles in Eucalyptus leaves and their relevance to exploration for buried gold deposits. Nature Communications 4, article number: 2274; doi: 10.1038/ncomms3614
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