Spatial distribution of chemical elements presented on geochemical maps frequently exhibits a polycentric character of its structure. Such a structure opens up possibilities for mathematical reproduction of its pattern. In our studies a simple model of the normal cone was used to model the structure of Cs-137 digital field. Our research has revealed that it can be used to analyze and reproduce the digital geochemical fields of mono- or polycentric structure of different complexity. Analysis of the obtained frequency histograms has shown that its form could reflect specificity of the spatial distribution of radiocesium concentration in monocentric anomaly and is even related to its parameters. The maximum frequency is divisible by the area of anomaly while the maximum value presents the maximum possible concentration of this anomaly. Results of modeling different cases of superposition of anomalies of different size and intensity were considered. It was shown that a comparative analysis of conic models and frequency histograms allowed describing and explaining of the shape of frequency histograms. It was demonstrated that a lognormal character of histograms that were frequently obtained in geochemical studies could have only shown the sampling within fragments of the monocentric or polycentric anomaly.