Science

"Gold leaf" trees discovered in the Australian outback

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Eucalyptus leaves showing traces of different minerals including gold
Eucalyptus leaf showing traces of gold
Gum leaf samples showing traces of manganese
Eucalyptus leaves showing traces of different minerals including gold
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Scientists from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) have discovered that eucalyptus trees in the Australian outback are drawing up gold particles from deep underground through their root system and depositing the precious metal in their leaves and branches. Rather than being a new source of "gold leaf," the discovery could provide a cheaper, more environmentally friendly way to uncover valuable gold ore deposits.

Using the science organization's Maia detector for x-ray elemental imaging at the Australian Synchrotron, the researchers were able to produce images that clearly showed deposits of gold and other metals in the structure of Eucalyptus leaves from the Kalgoorlie region of Western Australia that would have been untraceable using other methods.

"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," says CSIRO geochemist Dr Mel Lintern.

Because the leaf-bound "nuggets" are only about one-fifth the diameter of a human hair, prospectors aren't going to turn a profit by collecting leaf litter. Dr Lintern told ABC News that it would take the gold from 500 big eucalyptus trees growing directly over a gold deposit to produce a gold wedding ring. However, because eucalypt trees are so common across Australia, the discovery could provide mining companies with a cheaper and less environmentally damaging exploration approach than drilling.

"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," says Dr Lintern. "It’s a more targeted way of searching for minerals that reduces costs and impact on the environment."

The x-ray imaging technique also revealed the presence of other metals in the leaves, which opens up the potential for the technique to be used to detect deposits of metals such as zinc and copper, the researchers say.

The CSIRO team has published details of their discovery in the journal Nature Communications.

Source: CSIRO

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12 comments
nutcase
This is not the first time gold has been found growing on trees in the West Australian goldfields. Sandalwood oil is worth as much as gold and they are nearly all gone now. The spectre of prospectors roaming the goldfields with chainsaws is giving me nightmares. Goodbye trees. Won't be long now...
bergamot69
I suppose, given that eucalyptus leaves make up virtually all of the koala's diet, maybe it will be possible to 'pan for gold' in koala poo...
Buellrider
Sounds like this tree should be named Midas. It would seem that this tree is very valuable and should be protected from short term thinkers, better known as the human race.
micWeekly
Anything that helps mining companies explore for deposits is not environmentally friendly as it increases their efficiency of discovering deposits and by extension create more extremely damaging mines.
piperTom
You found a "geochemist" who thinks gold is toxic? Even for a plant, this is radical. I could believe the gold is *useless* to the tree.
lwesson
Gold is a noble metal and is largely inert. "likely toxic" does not even get close to being airborne. There are ways to make gold more reactive, but as a pure metal, it is pretty much staying put as gold. Now, gold is usually combined with other metals like silver and silver can "react". Also there are electrical properties to consider. It is more likely that the eucalyptus tree cannot do anything actively useful with gold and as such, it is simply eventually moved out with the transport of water going out through the leaves. That says much about the amount of gold in Australia!
Yes per finding out what is 60 feet below you. Mining drill cores could find out what is actually down there. Now that could become the nightmare.
There will not be chainsawing trees or Koalas, oh, gathering poop, at least in a place like Australia and Australians will have none of that. Perhaps all elephants & rhinos should relocate to Australia?
Having panned and sluiced for gold, such methods would not work per poop. Gold can simply float on off. Yes, gold can float when it is small... and here, we are talking microscopic small. You could harvest poop and process via chemicals but what a crappy job of it you would have for little return. Gold would have to hit 5 to 10 thousand dollars per Troy Ounce, and even then I would not be flushed enough with Gold Fever to do that.
Don Duncan
I doubt the plant roots pick up toxic elements. Gold is probably some sort of catalyst and then discarded after it has passed through the system.
What experiments were done to determine that it took 500 trees to produce one ring? Of what weight? Over how many months or years? This statement is meaningless without those details. It probably has no more validity than the "toxic" claim.
Ryandroid86
So you're telling me money does actually grow on trees...
Sebastian
Certainly adds credence to Geobotanical prospecting that the Chinese mastered a fair few centuries back.
I remember on speaking with either an AAM or Astrium rep at spatial@gov in Canberra last year, that they offer vegetation imaging for prospecting analysis as a fairly common service. Be interesting to see if they integrate this research into their services or it remains a boots on the ground approach.
ELM
That's all we need, got a eucalyptus tree in the back yard, ya get a slap in the face with the mining tax again. Where is that chainsaw?