SYDNEY (AFP) - Australian researchers have found tiny particles of gold hidden inside the leaves of eucalyptus trees, in a discovery they say could help prospectors discover new deposits of the precious metal.
Scientists from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) made the find in the resource-rich Kalgoorlie region of western Australia, which was the site of a major gold rush in the late 1800s.
Geochemist Mel Lintern said it appeared that the trees sucked up the gold particles from 30 metres below the ground through their roots.
"The eucalypt acts as a hydraulic pump - its roots extend tens of metres into the ground and draw up water containing the gold," he said.
"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."
In research published on Wednesday in the journal Nature Communications, the CSIRO said the leaf particles themselves would not trigger a new gold rush as they measure just a fifth of the width of a human hair and are visible only through advanced X-ray imaging.
But scientists could use a technique known as "biogeochemical sampling" to give an indication of the presence of gold beneath the surface.
"By sampling and analysing vegetation for traces of minerals, we may get an idea of what's happening below the surface without the need to drill," Dr Lintern said.
"It's a more targeted way of searching for minerals that reduces costs and impact on the environment." He said the method could also be used to find other metals such as zinc and copper.