Delineation of concealed banded iron formations (BIFs) below the Kurnool sediments in Palnadu Sub-basin, Macherla region, Cuddapah Basin through 3D inversion of aeromagnetic data

Abstract

Long linear high-intensity aeromagnetic anomalies are observed south of Vijayapuri to Macherla region, Cuddapah basin. The source of these magnetic anomalies is exposed and concealed BIFs with alternate layers of magnetite and quartzite. These BIFs are associated with greenstone belts of the Archean age capped by Kurnool and Cuddaph sediments. The review studies of the present work observed the (i) NW-SE, NE-SW, N-S and E-W trending magnetic linear features corroborated with the identified structural features, (ii) three bipolar magnetic zones (A, B and C) are identified from south of Vijapuri to Macherla, (iii) the nature of the magnetic anomalies at the south of Vijayapuri and south of Macherla alike and existing structural fabric might be responsible for the presence of different characteristics of the anomalies in these regions, (iv) 3D analysis of magnetic zones A, B and C show the presence of three isolated causative sources with susceptibility contrast of 0.115 SI existing from the surface to a depth of 2600 m from south of Vijayapuri to Muthukuru. (v) It is inferred from the 3D model studies, exposed BIFs at Vijayapuri region are dipping towards Macherla from the surface to extend up to a depth of 2600 m associated with amphibolites and might consist of alternative layers of magnetite and quartzite. (vi) The expression of NW-SE, NE-SW, N-S and E-W trending surface geological and magnetic structural lineations provided clues to the study area structurally disturbed and the accumulation of sediments in this region.