Multi-Modal Geophysical Characterization of Chromite Deposits in the Sittampundi Igneous Layered Complex, Tamil Nadu, India

Abstract

Chromite, a crucial source of metallic chromium, plays a vital role in a nation’s industrial and economic development. The Sittampundi Layered Complex (SLC) in southern India, an Archean-layered igneous complex, hosts chromitite deposits interlayered with anorthosite, gabbro, and pyroxenite, making it geologically significant. This study addresses a gap in chromite exploration in the SLC, applying a combined analysis of ground gravity, magnetic, very low-frequency electromagnetic (VLF-EM), electrical resistivity tomography (ERT), and self-potential (SP) data along three profiles. Data were systematically collected, processed, and analyzed to delineate subsurface chromitite bodies. Residual gravity and magnetic anomalies, coupled with SP inverted model and VLF-EM current density pseudo-sections, successfully identified high-density, conductive zones corresponding to chromitite mineralization. ERT sections revealed low-resistivity anomalies, further corroborating the results revealed by other methods. The integrated analysis of these geophysical methods provided consistent horizontal extensions and depth estimates of chromitite deposits across all profiles, with the highest depth range of 1 m to 60 m and the most frequent depths around 15 to 16 m. SP inverted model indicates that chromitite bodies in the SLC exhibit horizontal cylindrical geometry with shallow depth. Anomaly pattern correlations across multiple methods confirm the presence of chromite-rich zones, including probable new concealed zones. Notably, 2D forward modeling of residual gravity suggests deeper extensions of chromitite between 100 and 200 m. Integrated analysis of five geophysical methods corroborating each other has significantly enhanced the accuracy of subsurface investigations for chromite exploration in the SLC and proven its efficacy.