Resolving subbasalt geology from joint analysis of Gravity and Magnetic data over the Deccan Trap of Central India

Abstract

Deccan basalts which cover a large part of the Central India poses a sever constrain on the use of conventional techniques to image the sub-trappean sedimentary basins for hydrocarbon exploration. Gravity and magnetic investigation is conducted in part of the Deccan Syneclise in Central India to delineate the Mesozoic sediments hidden beneath the Deccan volcanic cover through joint analysis and modelling of the gravity and magnetic data. This integrated approach has brought out a series of asymmetric half-graben oriented in the E-W direction. Presence of high-density mafic intrusive bodies at shallow crustal depths of 4-6 km appears to be the characteristic feature of the Narmada-Tapti rift zone in the Deccan volcanic province, which might represent secondary magma chambers of the feeder dykes of the Deccan flood basalts. The pre-existing faults probably guided their ascent in the Deccan syneclise of Central India.