Geophysical methods as an aid in geological mapping and uranium exploration: a case study from Gangpur basin, Sundargarh district, Orissa, India

The role of geophysical methods in lithostructural mapping of thickly soil covered areas has been well recognized by geoscientists for a long time. The present paper highlights the effectiveness of magnetic and induced polarisation (IP) techniques in mapping poorly exposed rock units and also deciphering structures favourable for uranium mineralization at Jhamankela-Bhalulata areas (Long. 84 deg 30': Lat. 22 deg 19') of Gangpur basin, Sundargarh district, Orissa. Magnetic intensity data indicate three linear features representing basic intrusives (amphibolites) which are folded and faulted at places. Besides, three oval shaped and weakly magnetised bodies have been interpreted indicating presence of deep-seated granitic intrusives. Based on the results of IP surveys, scantily exposed carbon phyllites, considered to be marker beds in Gangpur Formation and showing major and minor/secondary folds are delineated. The inferred features like secondary folds, faults, and granitic intrusives are the suggested targets for uranium mineralization. (author). 8 refs., 6 figs