Natural gold particles in Eucalyptus leaves and their relevance to exploration for buried gold deposits

• Published in: Nature communications 2013-10, Vol.4 (1), p.2614, Article 2614
• Main Authors: Lintern, Melvyn, Anand, Ravi, Ryan, Chris, Paterson, David
• Format: Article
• Language: English
• Subjects: 704/158/47; 704/2151/330; Absorption; Australia; Eucalyptus - chemistry; Eucalyptus - metabolism; Geology - methods; Gold - metabolism; Humanities and Social Sciences; multidisciplinary; Plant Leaves - chemistry; Plant Leaves - metabolism; Plant Roots - physiology; Science
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms3614

Eucalyptus trees may translocate Au from mineral deposits and support the use of vegetation (biogeochemical) sampling in mineral exploration, particularly where thick sediments dominate. However, biogeochemistry has not been routinely adopted partly because biotic mechanisms of Au migration are poorly understood. For example, although Au has been previously measured in plant samples, there has been doubt as to whether it was truly absorbed rather than merely adsorbed on the plant surface as aeolian contamination. Here we show the first evidence of particulate Au within natural specimens of living biological tissue (not from laboratory experimentation). This observation conclusively demonstrates active biogeochemical adsorption of Au and provides insight into its behaviour in natural samples. The confirmation of biogeochemical adsorption of Au, and of a link with abiotic processes, promotes confidence in an emerging technique that may lead to future exploration success and maintain continuity of supply. The discovery of new gold deposits has declined by 45% over the past 10 years. Lintern et al. present new evidence for the occurrence of particulate gold in trees growing above buried mineral deposits, and propose vegetation sampling as a mineral exploration method.