Joint interpretation of potential field and drill core geochemistry data in the Gol-e-Gohar iron ore district, Southeastern Iran

This study presents a joint interpretation approach that integrates mixed Lp- norm regularized potential field inversions with geochemical data derived from drill core analyses to improve the delineation of iron ore mineralization. The investigation focuses on a major gravity and magnetic anomaly within the Gol-e-Gohar iron ore complex, located southwest of Sirjan in the Sanandaj-Sirjan metamorphic zone, where magnetite is the dominant iron ore mineral. To evaluate the inversion results, a comprehensive dataset from five phases of exploration drilling, comprising 193 boreholes, was used as a geological benchmark. This dataset includes laboratory measurements of total iron grade, iron oxide content and rock type information obtained from drill cores. Depth weighted gravity and magnetic susceptibility inversions were carried out to characterize subsurface anomalous sources and their spatial distribution. The resulting models were quantitatively compared with drill core geochemical measurements to assess their reliability in delineating iron rich zones. The comparison reveals strong agreement between the inverted models and borehole data in both the depth extent and lateral continuity of the mineralized bodies. However, gravity data inversion alone proved insufficient to distinguish magnetite-rich zones from lower-grade iron concentrations, as most iron-bearing rocks generate positive gravity anomalies. In contrast, the magnetic susceptibility model more effectively delineates high-grade magnetite zones and shows close correspondence with geochemical models. These findings indicate that minimum structure inversions of potential field data, even when performed independently and without explicit geological constraints, can successfully reconstruct lithologically plausible models of magnetite-dominated iron ore deposits.