Abstract
Fuzzy set theory is applied to prospecting the porphyry copper deposits in the north of Shahr‐e‐Babak, Iran. The geological layers incorporated into the porphyry copper model include: geochemical and geophysical anomalies; bedrock geology; proximity to east‐west lineaments; proximity to granitic and intermediate intrusive bodies; and proximity to alteration haloes. These data were processed in a raster GIS and fuzzy membership functions were evaluated for each data layer. Five intermediate maps were integrated using the fuzzy gamma operator with a value of 0.90 for gamma. Areas with high to moderate favourableness encompass well‐known porphyry copper deposits, namely Meiduk and Sara. Areas with low to moderate favourableness are justified for further exploration investigations.