Application of geostatistical studies for Identification of Au-Cu-Fe-W Anomalies in the Sehezar Valley of Tonekabon – Northern Iran.

Sehezar area is located in southern city of Tonokabon in Mazandaran province in north of Iran, and near the Tarom – Hashtjin belt. The existence of granitoid masses in the region can be important in terms of the potential of mineralization. The kriging geostatistical technique is used to predict the grade distribution, by using existing data and spatial correlation between them, which is described by the variogram. To identify the anomalous area, 50 stream sediment samples were collected from the area and analyzed by the ICP-MS method, and then interpreted. At first, the data were normalized and then the geostatistical analysis was used. Variogram studies showed that the spherical model is the best fitted model, and the spatial correlation range for the three elements of Au, Cu and Fe are approximately 350 m and for W is approximately 700 m. Finally, the estimation and estimation variance maps of the studied elements were prepared by using ordinary kriging geostatistical method with the spherical model on the GS+ software. Evaluating the results by calculating the root mean square error (RMSE) and calculating the mean absolute error (MAE) indicates the acceptable accuracy of variogram model. By studying the kriging estimation and kriging estimation variance maps, the anomal regions were introduced for the elements of Au, Cu, Fe and W in the case study. Due to the spatial correlation of the elements, it is concluded that this mass can be associated with iron-gold-copper deposits.