Geochemical exploration based on stream sediment data is, traditionally, an efficient method for identifying anomalous areas especially in the preliminary exploration stages for prospecting undiscovered outcropping or concealed mineral deposits. The materials of each stream sediment sample along drainage systems are derived from the weathering and erosion of all of its upstream lithology, and so, different upstream sources. Therefore, recognition and mapping of significant anomalies using stream sediment data are critical issues. In this regard, for efficient modeling of stream sediment data the area of influence of every stream sediment sample should be defined. In this research work, catchment basin modeling method was applied for mapping stream sediment geochemical anomalies in the northeast part of 1:100,000 geological quadrangle map of Pariz . For this catchment basin model was generated using digital elevation model (DEM) and the geological map of the study area digitized based on a UTM projection system. The data used in this study include: values of multi-element concentrations in stream samples, catchment basin area of the samples, and diversity of lithology types for each of the catchment basins. Local uni-element background concentration due to lithology was estimated by using weighted average method. The calculation also was carried out for uni-element residuals in each catchment basin. For separating geochemical anomalies from background, various methods have been applied. In this study, two methods of identifying geochemical anomalies,
