Stream sediment sampling is a well-known technique used to discover the geochemical anomalies. Various methods have been used in interpretation of stream sediment data in which geochemical landscapes are proposed to be modeled as either continuous or discrete fields. The sample catchment basin approach (SCBA) is one of the mostly-used discrete field techniques which its theoretical development date back to 1970s and 1980s. In SCBA, two main processes including correcting the geochemical background due to lithology and dilution correction are applied to avoid the creation of false anomalies and missing true anomalies and to more effectively delineation of anomalous catchment basins based on mathematical equation. The present study, knowing the shortcomings of exploratory geochemical studies, tries to take steps to improve and develop methods of geochemical interpretation of stream sediment data. To do these tasks, two areas are selected including portions of the1:100,000 Varzaghan and Kohpayeh geological maps. In general, certain chemical contents of stream sediments have positive relationships with areas of lithologic units in a catchment basin and have negative relationships with total area of a catchment basin, and these relationships have been used to model background concentrations and dilution effect, respectively. It should be noted that the area factor applied in all Equations is a horizontal (2D) projection of the area whereas in reality chemical composition of stream sediments is influenced by surfaces of lithologic units, which vary in three-dimensional (3D) space, as do the surfaces of sample catchment basins. To correct dilution effect from geochemical anomalies, the calculation of the three-dimensional area of catchments and rock units and its comparison with the results obtained from the calculations based on the two-dimensional area of the same basins in Varzeqan region was studied. The study area has 490 samples of stream sediments. According to mineral occurrence of copper mineralization and economic value, in this study, copper was selected as a reference element to the desired range. After calculating the three-dimensional area of all rock units in each basin as well as the True Sample Catchment Basins, the residual values of geochemical dilution correction based on the new relation presented by Mokhtari and Grossinejad (2015) based on SDR for n ( n = 0 , n = -0.25 and n = -0.5 ) were calculated and the geochemical anomalies were separated from the background using fractal concentration-area. The effectiveness of new equations in anomaly delineation was demonstrated by Normalized Density (ND) concept and the results showed how the parameters improved dilution correction of geochemical anomalies. The spatial position and actually, the distance and proximity of a lithological unit to the sampling site of the sediment discharge can play a role in amount of sediment delivery in that basin. On the other hand, under the same conditions in a stream basin consisting of two different lithological units, sediments related to that lithological unit in vicinity of the sample of the stream sediment may travel over shorter distance to reach the sampling point. Thi point is so useful in estimation of being anomalous or non-anomalous basin.. If there is mineralized source in much further lithological units, the resulting sediments should be traorted over longer distance and there would be a possibility of its dilution and reduction of its signal size during exploration by using stream sediment method. This distance is considered as the stream distance betwee lithological unit (j ) in catchment basin ( i ) and sample location of stream sediment ( Lji ). The weighted mean equation was solved in order to estimate the geochemical background concentration of the elements in two cases, considering the independent area variable ( Xij ) and the parallel area parameter divided by the length of the canal ( Zij = Xij / Lij ). To compare the results, two different approaches were considered. First, comparing the geochemical contexts obtained from the new and existing equations in each sample with its corresponding sample in the actual data set for each element. Second, comparing the geochemical background scatter distribution of all data obtained from the new and existing relationships for each element with the actual data. The results obtained from both methods showed that the length of the canal plays an important role in the downstream dilution of sediments from the mineralized areas and for all elements, Zij was closer to the value observed at the outlet of the basin.