3D inversion modeling of gravity data and its comparison with drilling data in the Negin exploration area, Yazd Province

Articles in Press

Authors

1 Faculty of Mining, Petroleum and Geophysical Engineering - Shahrood University of Technology

2 Kavak Aray Novin Mining Consulting Engineers Company

10.22044/jrag.2026.17461.1384

Abstract

Mineral exploration in areas where geological outcrops are concealed beneath thick alluvial cover is a major challenge in economic geology and exploration geophysics. In such environments, potential-field data, particularly gravity measurements, are valuable for detecting subsurface physical property variations; however, their quantitative interpretation is affected by inherent non-uniqueness and limited depth resolution. This study aims to address exploration challenges in alluvium-covered terrains by applying three-dimensional gravity inversion.

To overcome the problems of non-uniqueness and near-surface density concentration, the Li–Oldenburg inversion algorithm was employed. This approach reconstructs the three-dimensional density distribution by minimizing an objective function that incorporates depth-weighting functions and a reference geological model. The method was applied to gravity data from the Negin exploration area in Yazd Province, central Iran, where surface indications of mineralization are scarce. The subsurface was discretized into rectangular cells, and the inversion was performed under data-fitting constraints.

The inversion results reveal a high-density intrusive body at depths of approximately 60 to 200 m, consistent with the regional geological framework. To validate the geophysical model, the inversion outcomes were compared with exploratory drilling data. Drilling at the center of the gravity anomaly confirmed the presence of a mineralization-related granodioritic body at a depth of about 61 m, demonstrating a strong agreement between modeled results and subsurface conditions. These findings indicate that integrating three-dimensional gravity inversion with limited geological information is an effective strategy for improving drill targeting and reducing exploration risk in alluvial-covered regions.

Keywords


Articles in Press, Accepted Manuscript
Available Online from 14 July 2026

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