AsianScientist (Oct. 23, 2013) – Researchers in Australia have detected gold particles in the leaves of Eucalyptus trees, a sign that indicates the presence of deeply buried gold deposits nearby.
Traces of gold are sometimes found in soils surrounding Eucalyptus trees; however, without heavily disturbing the area and digging to great depths it is difficult to determine whether the trees are indeed located above as yet undiscovered gold resources or if the gold particles were blown there by wind.
The study, published in Nature Communications this week, may lead to a new way of locating buried gold deposits in difficult to reach locations without the need for invasive land excavation.
To identify naturally occurring gold particles in the leaves, twigs and bark of Eucalyptus trees, geochemist Dr. Melvyn Lintern and colleagues at CSIRO used a technique called X-ray imaging. Subsequent field samples and greenhouse experiments suggest that minute gold particles, at concentrations not harmful to the tree, are absorbed by the roots and transported to its extremities, such as leaves, where the highest concentrations were observed.
“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,” said Lintern, who added that the “nuggets” are about one-fifth the diameter of a human hair.
The researchers believe that the trees, growing above a gold deposit located 35 meters underground, tapped into the deposit while searching for moisture sources under drought conditions.
Considering the 45 percent decrease in gold discovery over the past decade, this link between climate, vegetation growth and buried gold deposits could prove instrumental in developing new technologies for mineral exploration, the authors say.
Source: NPG; Photo: CSIRO.
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