In the geochemical stream sediment survey, obvious differences in geochemical backgrounds of different geological bodies will affect the anomaly delineation and even lead to enhancement of anomalies irrelevant to mineralization, which weakens the mineralization-related weak anomalies. In this paper,the influence of step effect data on the fractal distribution form is discussed from the mathematical view based on the superposition law of fractal distribution, and an improved method for eliminating step effects in concentration-area fractal theory is proposed.In this method, the authors divide the study area based on geochemical background and then discuss fractal distribution forms respectively.The result shows that this method can accurately filter irrelevant lithology information and identify weak anomalies caused by mineralization in low-background sub-zone. It is applicable to the extraction of geochemical mineralization-related anomaly in the areas seriously affected by lithology.
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