Constrained modeling and integrated interpretation of heliborne geophysical data in Kaladgi basin, Karnataka

The Meso-Neoproterozoic Kaladgi Basin in the northern part of Dharwar Craton exposes sediments of Kaladgi Supergroup. These Kaladgi sediments unconformably overlie the basement Peninsular Gneiss and Dharwar Supergroup in the south and are concealed under Deccan Traps in the north. High resolution heliborne magnetic, GRS and TEM data were collected over Kaladgi Basin to explore the basement structures and locales of structurally controlled uranium mineralisation within the basin with a focus on Kerur-Sirur Fault (KSF). The ENE-WSW trending Kerur-Sirur fault in the central part of the fl own block extends over a length of 25 km along Kerur-Katageri-Sirur-Kamatagi tract. It juxtaposes basement Closepet Granite with the upper most Kerur Formation of Badami Group of Kaladgi Supergroupp. Magnetic lineaments and breaks suggest that the major structural trends are in NE-SW, NW-SE, ENE-WSW and E-W directions. Aeromagnetic data reveal short wavelength linear magnetic anomalies trending in ENE-WSW direction coinciding with the Kerur-Sirur fault. 2D forward modeling along a N-S profile revealed that the Kerur-Sirur fault is a high angle reverse fault with the north block overriding the south block with an estimated throw of ~150 m. This reverse fault cutting across the Meso-Proterozoic cover sediments of Kaladgi basin unconformably overlying the fertile Closepet Granite basement suggest that the area has the potential to host uranium mineralisation akin to Gogi deposit, Proterozoic Bhima Basin, Karnataka. The fault as interpreted from geophysical data is under active exploration and yielding favourable results. (author)