Geophysical Exploration for Mineral Potential in Sausar Fold Belt: Insights from Gondia District, Maharashtra, and Balaghat District, Madhya Pradesh, India
Authors: Kant Abhay , Kumar Rajan , Shankar Uma , Bakshi Ansuman , Singh Alok Kumar 
Published: July 2024

Abstract

The study of regional gravity and magnetic surveys, combined with geospatial techniques and detailed geological analysis, has identified two promising blocks: Arjuni-Kindgipar block and Kachekhani block. These blocks have been selected for integrated detailed geophysical surveys, including magnetic and electrical methods such as Resistivity, Induced Polarization (IP), and Self-Potential (SP). The goal is to identify subsurface geological structures like faults, fractures, shear zones, and litho-contacts, which are crucial for mineral exploration. This information is essential for proposing borehole locations and determining the depth needed to intersect mineralization zones. In the Arjuni- Kindigipar block, the magnetic values ranged from -347.31 nT to 359.15 nT in the study area. The isolated high anomaly patches in the north-south direction are recorded in the central part of the study area which abruptly disrupts to monotonicity of the contour patterns of the magnetic anomaly. It is inferred as a fault. The two zones L1 and L2 of low SP value lie in the vicinity of a high chargeable zone at 60 meters depth in the south-western direction and high surface chargeability H1, respectively which may be considered as the signal originating from sulphide mineralization. The values of L1 and L2 are -23mV and -25mV, respectively. These values are not very large but still stand out from the background values and might have been caused due to the disseminated nature of the body/bodies. These two low zones corroborate well with IP/Res values in the map and may point towards a possible mineralization in the area. The 3-dimensional view of resistivity and chargeability shows the horizontal slice of chargeability at 60 meters depth from the surface and resistivity sections at 200 meters interval for better visibility. The chargeability slice shows an elliptical high zone trending NW-SW in the southeastern part of the study area. The slice also shows one linear high zone which starts from the southernmost part of the study area trends NE-SW and traverses through the whole study area. In the Kachekhani block, the magnetic values ranged from -104 nT to 55 nT. A low magnetic zone L1 exists in the north-eastern part of the study area having a strike direction of NE-SW, extending along the south-western direction being briefly interrupted in the west with moderately low values of around -40nT. The lowest value in zone L1 is around -90nT. The tightly placed contours between H1 and L1 trending NE-SW show the presence of some important geological features like fault/fracture. The occurrence of high SP values in the vicinity of low chargeability zones and moderately high resistivity zones also points towards its relevance to locate subsurface hydrogeological features and its inconclusiveness in locating any sulphide zones. The 3D view of IP and resistivity shows a continuous relation of high resistivity zone with high chargeability values. Also with depth, the values of IP increase from 6.5 mV/V at the surface to 12.5 mV/V at 60 meters depth. The high chargeability zone also increases in width and is maximum along 2391000 meters northing. The low resistivity zones might indicate a shear zone along which the fluid has intruded bringing down the resistivity values.