Separation of geochemical anomalies using inverse distant weighting (IDW) and concentration-area (C-A) fractal modeling based on stream sediments data in Janja region, SE Iran

Abstract

In this study, the Inverse Distant Weighting (IDW) and the Concentration –area (C-A) fractal methods were used for identifi cations of geochemical anomalies in Janja region, SE Iran. Eight elements (Au, Cu, Mn, Zn, Fe, As, Mo, and Pb) from 300 stream sediment samples were used. The studied area was gridded by 250 m×250 m cells. Estimation of unsampled locations were carried out by inverse distant squared weighting (IDWS) method. Geochemical maps were generated. Log- log plots of cumulative frequency of elemental concentrations versus related areas were constructed. Threshold values were obtained by fi nding break points in the log-log plots. There were four geochemical populations for As, Fe, Mo, Pb and Zn and fi ve geochemical populations for Au, Cu, and Mn. The resulted geochemical anomaly maps obtained from fractal modelling showed that Anomalies of Zn, Mo, Mn, Fe, Cu and As located in southeastern part of study area. There was a good correlation between faults and elementals anomalies. It can be concluded that mineralization occurred along the faults. There was a correlation between anomalies and sedimentary rocks (alluvium and recent alluvium sediments) in SE part of study area. Gold anomalies were located in the NW parts of the studied area. There was a strong relationship between the location of Au anomalies and fault systems in the NW parts of the studied area. Iron concentrations were sporadic and correspond to the sedimentary volcanic rock and turbidites.