Application of Geophysical Methods as an Aid to Shear Controlled Uranium Mineralization along Pakni-Asnapara-Darhaura Tract,Surguja District, Chhattisgarh

摘要

Geophysical methods have been extensively used for delineation of structural features such as shear zones, faults and fractures which often control and host economic mineralization. Multiple parallel and sub-parallel, shear zones hosting vein type uranium mineralization occur in Surguja shear zone comprising basement gneissic complex as inliers in Gondwana sedimentary rocks. The geophysical signatures of one such shear zone near Pakni-Asnapara-Darhoura are investigated employing magnetic and induced polarization methods. Interpretation of magnetic data has revealed a broad 'magnetic low' trending in ENE-WSW direction and is attributed to intense shearing and fracturing in the host rock. Within this low zone, basic bodies responsible for remobilization of uranium due to the high geothermal gradient are identified. Disposition of these basic bodies has indicated the presence of NNW-SSE trending faults and continues towards north. Induced polarization data have indicated that the mineralized zones which are characterized by high chargeability and low resistivity anomalies follows the trend of the shear zone.