Regional-scale exploration targeting of REEs associated with Kiruna-type Iron Oxide-Apatite mineralization in the Bafq-Saghand metallogenic province, Central Iran

Abstract

The Bafq-Saghand metallogenic province, situated in the Central Iranian geo-structural zone, hosts world-class Kiruna-type Iron Oxide-Apatite (IOA) deposits, accompanied by local Rare Earth Elements-Uranium-Thorium (REEs–U–Th) enrichment. Its favorable geological setting holds significant potential for the discovery of REEs mineralization. However, the processes governing the formation, development and preservation of REEs are inadequately understood. Recognizing the processes leading to REEs formation and mapping their spatial expressions are crucial factors for mineral prospectivity mapping and subsequent exploration activities. This research aims to delineate exploration targets for REEs associated with IOA deposits, employing a Mamdani-type fuzzy inference system (FIS) technique and concentration–area fractal method. The regional-scale targeting criteria for IOA-associated REEs deposits were identified using mineral systems approach. The inputs for the mineral prospectivity model were the spatial proxies derived from geoscientific datasets comprising geological, remote sensing, geophysical, and geochemical data. The output prospectivity map highlights high-prospectivity REEs target areas covering approximately 10% of the entire region, displaying an NNW-SSE trending pattern similar to the crustal faults of the region, mainly associated with metasomatized acidic volcanic and metamorphosed volcanic rock units. This research led to identification of prospective target areas, where detailed project-scale exploration study is recommended and the demonstrated strategy in this research can be applied to demarcate exploration targets in similar geological terranes elsewhere.