Researchers from Australia say that the presence of the particles in a eucalyptus（桉树） tree's foliage²（叶子） indicates that deposits are buried many metres below.

 

They believe that the discovery offers a new way to locate the sought-after metal in difficult-to-reach locations. 

 

The research is published in the journal Nature Communications.

 

Dr Mel Lintern, a geochemist from Australia's Commonwealth³ Scientific and Industrial Research Organisation⁴ (CSIRO), said: "We've found a lot of the easy deposits in Australia and elsewhere in the world as well. 

 

"Now we are trying to tackle finding these more difficult ones that are buried beneath tens of metres of river sediments⁵ and sand dunes⁶. 

 

"And the trees are providing us with a method to be able to do this."

 

 

Gold particles have been found around the soils of eucalyptus trees, but the researchers confirmed that the plants were taking in the element. 

 

Using the Australian synchrotron - a vast machine that uses X-rays to probe matter in remarkable⁷ detail - they found traces of gold in the leaves, twigs⁸ and bark of some trees.

 

The amounts of the precious metal were tiny.

 

"We've done a calculation, and found that we need 500 trees growing over a gold deposit to have enough gold in the trees themselves to make a gold ring," said Dr Lintern.

 

However, the presence of the particles pointed⁹ to greater riches buried more than 30m below.

 

Dr Lintern said: "We believe that the trees are acting¹⁰ like a hydraulic¹¹（液压的） pump. They are bringing life-giving water from their roots, and in so doing, they are taking smaller dissolved gold particles up through the vascular¹² system into the foliage."

 

Currently, the metal is found in outcrops（露出地面的岩层）, where the ore appears at the surface, or it is detected through exploratory drilling. 

 

But the researchers said that analysing vegetation could offer a better method to find untapped gold deposits.

 

Dr Lintern said: "Not only do we believe it is a way of stretching the exploration dollar further, because exploring for these deposits can be quite expensive, it also minimises the damage to the environment because we are taking a very small sample from the trees themselves, as well as the leaves and twigs on the ground."

 

The researchers said the technique could also be used to find other minerals such as iron, copper¹³ and lead in other parts of the world.

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