Abstract. A two-stage fuzzy inference system (FIS) is applied to prospectivity modelling and exploration-target delineation for rare earth element (REE) deposits associated with
carbonatite–alkaline complexes in the western part of the state of Rajasthan in India. The design of the FIS and selection of the input predictor
map are guided by a generalised conceptual model of carbonatite–alkaline-complex-related REE mineral systems. In the first stage, three FISs are
constructed to map the fertility and favourable geodynamic settings, favourable lithospheric architecture for fluid transportation and favourable
shallow crustal (near-surface) emplacement architecture, respectively, for REE deposits in the study area. In the second stage, the outputs of the
above FISs are integrated to map the prospectivity of REE deposits in the study area. Stochastic and systemic uncertainties in the output
prospectivity maps are estimated to facilitate decision-making regarding the selection of exploration targets. The study led to the identification
of prospective targets in the Kamthai–Sarnu-Dandeli and Mundwara regions, where detailed project-scale ground exploration is
recommended. Low-confidence targets were identified in the Siwana ring complex region, north and northeast of Sarnu-Dandeli, south of Barmer, and
south of Mundwara. Detailed geological mapping and geochemical sampling together with high-resolution magnetic and radiometric surveys are
recommended in these areas to increase the level of confidence in the prospectivity of these targets before undertaking project-scale ground
exploration. The prospectivity-analysis workflow presented in this paper can be applied to the delineation of exploration targets in geodynamically
similar regions globally, such as Afar province (East Africa), Paraná–Etendeka (South America and Africa), Siberia (Russia), East European
Craton–Kola (eastern Europe), Central Iapetus (North America, Greenland and the Baltic region) and the pan-superior province (North America).