Geochemical modeling of the Cu-Ag deposits from the Lubin-Głogów Copper District (Poland) supported by lithological modeling

The most important reasons for the limited credibility of 3D geochemical models of the Cu-Ag deposits (The Lubin-Głogów Copper District) are unfavorable statistical characteristics of the main metals (Cu, Ag), and the unfavorable structure of their variability with a relatively poorly marked non-random component of variability. It is hoped that the accuracy of geochemical models can be increased by previous lithological modeling of a given deposit. This is due to significant differences in mean Cu content in both the main lithological series (carbonates, shales and sandstones) and individual lithological units within them, which justifies separate geochemical modeling of each. The paper presents the results of the comparison of the reliability of 3D modeling of Cu content carried out in both individual and main lithological units of the Cu-Ag Rudna deposit (The Lubin- Głogów Copper District). The 3D lithological models were made using ordinary kriging (main lithological units) and Plurigaussian simulation (individual lithological units). The 3D estimation of Cu content within lithological models was carried out using the ordinary kriging (OK ) and squared inverse distance (ID2) methods. The verification of the accuracy of Cu estimates in the 3D model using spot samples of the test data set has shown only a slight increase in the accuracy of the estimates of Cu content within the individual lithological units of the shale series compared to the estimates of Cu content in the whole main lithology. In most cases, 3D models of Cu content carried out using the ordinary kriging method are slightly more accurate than the analogous squared inverse distance weighting method.