عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Several statistical methodologies have been developed for separating anomalous values from background values leading to determination of anomalous areas. These methods range from simple approaches to complex ones and include methods such as Statistical Parameters of Distribution (as a non-structural method) and U Spatial Statistic (as a structural method). The second group takes the sampling locations and their spatial relation into account for estimating the anomalous areas. The U Spatial Statistic method is one the most important structural methods which carries out the statistical analysis of the data by considering the spatial location of the samples and without judging from a geochemical point of view. It then separates the subpopulations and determines the anomalous areas. In the present study, the surface samples from the Parkam exploration district were used in order to draw a comparison between the capability of two methods of non-structural methods (Statistical Parameters of Distribution and Gap Statistic) and U Statistic (structural method) in separating anomalous values from the background and providing the anomaly map for grade values of Pb and Zn. Results suggest that the samples indicated by U Statistic and Gap Statistic methods as anomalous are more regular and less dispersed compared to those indicated by the method of Statistical Parameters of Distribution. Both Gap Statistic and U Statistic methods have shown almost similar results for estimating threshold and separation, but U Statistic method is even better than Gap Statistic because the U Statistic method devotes a new value to each sample which can be combined with other methods. Thus the map of prospective areas for Pb and Zn in the exploration district has been prepared using the U Statistic method.