Biogeochemistry: Does gold grow on trees?

The detection of gold particles in the leaves of Eucalyptus trees provides a new way to locate buried gold deposits according to a study in Nature Communications this week. These findings could lead to the discovery of deeply buried gold deposits in difficult to reach locations.

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. Melvyn Lintern and colleagues use a type of X-ray imaging to identify naturally occurring gold particles in the leaves, twigs and bark of Eucalyptus trees that could help to identify gold deposits without the invasive excavation of land. The team suggest that the trees, growing above a gold deposit located 35 metres underground, tapped into the deposit while searching for moisture sources under drought conditions. Field samples and greenhouse experiments carried out by the team 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.

Considering the 45% 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.

doi: 10.1038/ncomms3614

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