3D Sparse norm inversion of gravity and magnetic data: A case study of Gol-e-Gohar mine in Iran

This study employs a constrained mixed Lp norm inversion to assess the efficacy of geophysical potential field methods in delineating high-grade iron mineralization zones within the Gol-e-Gohar No. 2 deposit, located in the Sanandaj-Sirjan zone of southwest Iran. Given the considerable density and susceptibility contrast between iron ore, particularly the massive Kiruna-type magnetite ± apatite mineralization, and the surrounding metamorphic host rocks, extensive ground-based gravity and magnetic data were collected across a survey area spanning 1600m × 900m.  To validate the effectiveness of the sparse norm inversion algorithm, two synthetic models were initially evaluated. These models included a dipping prism and two vertical prisms. Subsequently, after essential gravity and magnetic data corrections, the algorithm was applied to the acquired field data. The accurately recovered models obtained through the iterative inversion process were visually presented through four cross-sections covering the primary anomalous region, revealing a robust spatial correlation between high-density contrast and high-magnetization zones. Further development of 3D reconstructed models for density contrast and magnetic susceptibility demonstrated significant consistency with geological data obtained from exploratory boreholes, effectively delineating three distinct mineralization zones with vertical expansions ranging from 100 to 300 meters. These zones were characterized by magnetized regions enclosed within the dense rock formations.

3D Sparse norm inversion of gravity and magnetic data: A case study of Gol-e-Gohar mine in Iran Keywords:

Gravity data , Magnetic data , Mixed Lp norm inversion , Gol-e-Gohar iron deposit , exploratory boreholes