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

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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.
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... Younger trees are also found to have tap roots possibly reaching down to 35m depths (Lintern et al., 2013). The soil has a high clay content which leads to a high water holding capacity and little effect of precipitation on soil water content at depth 305 below 50cm. ...
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... Thus, the production of and demand for these resources is increasing. During the past several years, people have focused on how to quickly extract mineral resources and proposed various prospecting methods, such as remote sensing [1][2][3][4], geophysical [5][6][7][8], and geochemical methods (rock, soil, and plant geochemistry) [9][10][11][12][13]. However, the environmental destruction and problems that result from unsustainable mining practices are often overlooked. ...
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