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

Abstract

Major aim of this study is to define the copper and gold anomalies 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 case study is situated in Alborz-Azerbaijan structural zone. Elements related to Au and Cu hydrothermally mineralization were selected for this study, according to ore deposit types of the study region. Staged factor analysis was carried out in four steps. Consequently, all 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, Au and Cu were plotted and threshold values were determined in order to a generation of elemental distribution 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.