Description of gold and copper anomalies using fractal and stepwise factor analysis according to stream sediments in NW Iran

This aim of the study is to describe the copper and gold anomalies, by using the combination of the Concentration–Number (C–N) fractal and the stepwise factor analysis, based on stream sediment samples in Lahrud 1:100,000 sheet, NW Iran. The field of study is situated in Alborz–Azerbaijan belt. According to index ore deposit types, elements related to Au and Cu hydrothermal mineralization were selected for this study. Consequently, all the noise elements were removed after applying four steps of factor analysis and As, Sb, Sn, W, Co, Mn, Zn, Ti, Ba, Ni, Cr, Au, Cu, and B were grouped in the five factors. Cu and Au are grouped on factor 4 of the last step (FAC4–4). The C–N log–log plots for factor scores were plotted and threshold values were determined in order to a generation of elemental geochemical maps. The anomalous areas for metallic elements specifically copper and gold, are located in the NW and SW parts of the region which show a correlation between alteration zones, faults, and intrusions.