Research team finds traces of gold in tree leaves

October 24, 2013

A team from Australia’s national scientific agency, the CSIRO, found tiny specks of gold in eucalyptus trees in Australia’s Outback.

Although the amount of gold found in the leaves is so minute that it cannot be seen with the naked eye, the discovery does indicate that certain types of trees could provide ways to locate mineral deposits.

The discovery was made in the leaves and branches of eucalyptus trees in the remote Kalgoorlie area of Western Australia. The scientists concluded that root systems, searching for moisture during times of drought, suck up water containing the precious metal from ore deposits lying up to 30 m (100 ft) underground, the Independent reported.

According to the scientists, whose findings were published in the online journal Nature Communication, the gold particles are drawn up through the tree’s root system. “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,” Melvyn Lintern, who led the project, 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… Eucalyptus trees are so common that this technique could be widely applied across Australia.”

Nigel Radford, a former geochemist with Newmont Mining, told ABC radio it was “very, very important for the future of mineral exploration.”
Mining companies, which partly sponsored the research, have already begun sampling leaves for gold, according to Lintern, who said the technique – an environmentally friendly method of exploration – could also be used to find metals such as copper and zinc.

The unusually long, extensive roots of a gum tree, penetrating up to 40 m (131 ft) underground, act as a “hydraulic pump,” said Lintern, whose team collected leaves, branches and bark, and examined them under a powerful X-ray microscope. He told ABC: “We weren’t expecting this at all. To actually see the gold particles in the leaves was quite a ‘eureka’ moment for us.”

Bushes and soil beneath the trees could also be tested for gold traces.

Australia is the world’s second biggest gold producer after China, mining nearly 80 tons of the metal last year. With global reserves decreasing, exploration companies are now hunting for deposits that lie deep underground and are difficult to detect.

Lintern said: “As far as we know, this is the first time that anyone has seen gold in any biological tissue, and it just happens to be a eucalyptus leaf.”

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