Hydrothermal Ni prospectivity analysis of Tasmania, Australia

Abstract

A two-pronged approach involving GIS-assisted manual prospectivity analysis and GIS-based fuzzy prospectivity analysis was used for identifying the most prospective ground for hydrothermal Ni deposits in Tasmania. The manual analysis involved (1) defining the process model and identifying key mineralization processes responsible for formation of hydrothermal Ni deposits; (2) manually estimating the probability of occurrence of each mineralization process based on the available information; (3) combining the above probabilities to derive overall probability of occurrence of hydrothermal Ni deposits in various geological regions of Tasmania. The Geological Information System (GIS)-based analysis involved representing the mineralization processes in the form of spatial predictor maps and using a fuzzy logic model to integrate the predictor maps and to derive a hydrothermal Ni prospectivity map of Tasmania. The results indicate that the most prospective areas for hydrothermal Ni in Tasmania are located along the boundary between the Dundas and Rocky Cape regions. This study further indicates that parts of the Ferrar Large Igneous Province (LIP) in central and Eastern Tasmania, which are presently considered non-prospective, could be potentially prospective for hydrothermal Ni deposits. A major advantage of the approach is that it can be easily adapted and applied to hydrothermal Ni prospectivity analysis worldwide.