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D. Cicchella, A. Lima, M. Birke, A. Demetriades, X. Wang, B. De Vivo

Mapping geochemical patterns at regional to continental scales using compositesamples to reduce the analytical costs

Journal of Geochemical Exploration 124 (2013) 79–91
journal homepage: www.elsevier.com/locate/jgeoexp


The use of composite samples to reduce the time and cost of chemical analysis is discussed. It is shown whencomposite samples can be used without affecting predefined project objectives. Furthermore, it is also demonstratedwhen they should not be used, and also how much information is lost due to their use.The study presents a comparison of data concentrations of some major (Al2O3, CaO, Fe)and trace elements (Cd, Co, Cr, La, Rb, Sr, Th, Tl, U, Zn) in European topsoil and subsoil produced byFOREGS (Forum of European Geological Surveys) and two other data sets derived by compositing the five individualsamples in each 160×160 km cell of the Global Terrestrial Network (GTN); the first by physicallycompositing the samples, and analysing the composites, and the second by artificially compositing the samplesin each GTN cell.
The three soil databases were compared statistically and spatially to quantify the significance of the differences.The results of this study clearly demonstrate that composite samples can be used effectively toshow broad continental-scale element distribution patterns; their use may not be effective if the goal is tohighlight local geochemical anomalies. It is concluded that compositing samples for continental-scale surveysis a time- and cost-effective procedure, especially for reducing the costs for chemical analysis.