An exploratory model for sediment-hosted lead and zinc deposits by using the fractal method in Yazd block- Central Iran

Abstract

Structure processes have a significant role in forming sediment-hosted lead and zinc deposits. On other words, they are formed in an individual pattern located in the related rift basins. So, the first-order, the second-order, and the third-order basins have been created. Faults operate as the conduct of ore-bearing fluid and the bounding-the second-order basins. By starting rifting, hydrothermal fluid enters a sedimentary basin and as a result of the extending faults, it creates convection cells confined by faults. Therefore, structural processes are the main control factor for these deposits. Also, factors controlling the mineralization are recognized by spatial analysis methods. In this study, to identify controlling factors and present an exploratory pattern for sediment-hosted Pb-Zn deposits in the southern part of the Yazd Block, the fractal (Box- counting) method has been used. This method was utilized to estimate the distance of sub-basins which are the host of sediment-hosted Pb and Zn mineralization for the first time. The results of this method depicted three different populations representing three factors controlling the mineralization in the studied area. These results were consistent with the basin structure which has been formed from three sub-basins. Therefore, three populations obtained from the fractal analysis showed the dimensions of three sub-basins in the studied area. The distance between mineral deposits in the third-order basin obtained about 8 Km while it is about 31 Km for the second-order basins. So, three second-order basins were recognized in which the distance between sub-basin numbers 1 and 2 is about 30 Km while it is about 60 Km between sub-basin numbers 2 and 3. Based on this exploratory model, there could be another second-order basin between sub-basin numbers 2 and 3. According to reports and literature, no other deposit has been discovered between them until now. So, based on the suggested model, there is a possibility of other deposits occurring between sub-basins numbers 2 and 3.