A GIS-based fuzzy logic method for mineral potential mapping: An experiment with a geological map of the Parry Islands, Northwest Territories, Canada

The application of fuzzy logic in a GIS framework is a valuable method to assist in mineral resource assessments (MRA) in areas where data are sparse. This study uses a digital geological map, backed by a digital geological data model, derived from published legends and reports. Together they function as a 'spatial-attribute relational data model' that provides evidence, in the form of derivative maps, to support mineral potential according to deposit model criteria. A knowledge-base is created with fuzzy membership functions linked to the classes of each derivative map that indicate favourability between geological features present in the database with those required by model criteria. A fuzzy-logic-based 'inference net', as implemented in the GIS modelling language, is used to combine spatial evidence to determine mineral resource potential for three mineral deposit sub-types: (1) MVT Pb-Zn, (2) Sedimentary Cu and (3) Sediment-Hosted Sulphides. This method is shown to be valuable for providing an 'audit trial' for the complex decision-making process associated with resource assessment; it provides a means for experimenting and testing various hypotheses and viewpoints associated with mineral deposit models, and mimics some aspect of how geologists determine mineral potential for a region using information provided in geological maps and mineral deposit model literature.