Application of a fractal method relating concentrations and distances for separation of geochemical anomalies from background

This paper introduces a new method, the element concentration-distance (C-D) model, for separating geochemical anomalies from background based on a fractal approach. The method is derived from Mandelbrot's radial-density law by replacing the density with concentration, which in turn follows the power-law of fractals. The variability of the element concentration as a function of distance from sample sites reveals two different fractal distributional patterns acting within two scale ranges. Therefore, this model can be used to effectively separate geochemical anomalous areas from background. The method has been tested on three data sets from Zhejiang Province in China, two from stream sediment samples (n = 3815) and one from lithogeochemical samples (n = 329). We compared the anomalous area created using thresholds from various methods on the same data against the known deposits and occurrences, and found that the C-D model is superior to the other methods. (C) 2002 Elsevier Science B.V. All rights reserved.