Gold in trees and hidden anomalies in diverse regolith terrain: A case study at Pelangio Mamfo Concession, Ghana

Abstract

Deep-rooted trees absorb minerals including gold from the weathered materials and translocate the resources to different structures of their body. This occurs as part of general elements translocation process and those considered toxic to trees move to the extremities and other preferential areas away from the tree biological functioning zones. After investigation of several plant species, Sapele (Enthandrophragma cylindricum) tree bark was used as supplementary medium to soils in areas under cover; sixteen samples were collected from roots, barks, twigs and leaves. Fire assay was used and analysis of the results divulged differences in gold signatures in samples. The highest gold expression of 1045 ppb was found in bark samples with a minimum of 9 ppb occurring in twig samples. Gold averages from Sapele (i.e., from the leaves, twigs, roots and bark sampled) were 116.44 ppb, 89.53 ppb, 209.25 ppb, and 352.31 ppb, respectively. The high gold in leaves over twigs may be an attribute of aeolian gold contamination coalescing with the absorbed gold. Roots being close to source of mineralization had lower gold than bark samples and this is accredited to gold toxicity and its subsequent movement away from the xylem to the bark. The best part of a tree considered appropriate as a supplementary medium to soil samples is bark samples.