Aeromagnetic and gamma-ray spectrometric data interpretation for uranium exploration - south eastern margin of the Chattisgarh Basin, India

Airborne surveys were conducted along the south-eastern margin of the Chattisgarh Basin - Singhora Basin and Sonakhan greenstone belt by the Atomic Minerals Directorate for Exploration and Research in 2000 with E-W flight lines covering 19800 linekm. Preliminary processed aeromagnetic data were corrected for IGRF, heading and lag and levelled using tie line data. Based on the amplitude, frequency and textural characteristics of enhanced magnetic images, litho-structural information of the area was deciphered. Semi-quantitative interpretation of aeromagnetic data employing Euler's technique facilitated identification of source body locations along with depth estimates. Airborne Gamma Ray Spectrometric (AGRS) data were processed for altitude attenuation, radon interference and stripping corrections. The radiometric ternary image of the processed data shows good correlation with surface geology of the area. Radiometric anomalies were extracted from the derived concentrations based on mean and standard deviation of Uranium, U/Tb and U2/Th data sets. Finally, integrated Geographical Information System (G15) analysis of inferred faults and lineaments from aeromagnetic data and uranium anomalies mapped from AGRS data were used for extracting zones favourable for uranium mineralisation. Qualitative and quantitative analysis of aeromagnetic and AGRS data and integration of the results on a GIS platform thus helped in identifying target areas for further exploration. (author)