Unveiling concealed Banded Magnetite Quartzites (BMQs) through high-resolution aeromagnetic surveys: New insights from the Nellore Schist belt of Eastern Dharwar Craton, India

In the Chundi–Malakonda–Ayyavaripalle region of the Nellore Schist Belt, part of the Dharwar Craton, six north-south (N–S) trending, elongated Banded Magnetite Quartzite (BMQ) bands have been identified. These bands are exposed within meta-rhyolite and quartzite formations and are associated with biotite–muscovite schist. The BMQs vary in width from 20 to 40 meters and extend in length from 1.5 to 4.5 kilometres. ​ High-resolution aeromagnetic surveys with a terrain clearance of 80 meters have revealed significant magnetic anomalies over the study area (source: https://geodataindia.gov.in). These anomalies range from –3,900 to +5,000 nanoteslas (nT), indicating a high concentration of magnetic minerals within the exposed BMQs, designated as Bands 1 to 6. In addition to these exposed bands, a concealed, parallel, N–S trending BMQ band has been identified through detailed analysis of aeromagnetic data. 2D and 3D Interpretation of the magnetic anomalies suggests that meta-rhyolites exist up to an average depth of 250 m from the surface and might be associated with BIF bands at depth. This depth extent highlights the substantial vertical continuity of the magnetite-rich formations in the region. The integration of geological mapping and aeromagnetic data provides a comprehensive understanding of subsurface geology, highlighting the potential for significant mineralization within the Nellore Schist Belt.