Gravity field, deep-seismic sounding and crust-mantle structure over the Cuddapah basin and Dhawar Craton of India

Magmatic underplating beneath the Rajmahal Traps: Gravity signature and derived 3-D configuration

“…Satellite derived gravity maps of the Indian region show a long wavelength anomaly centred over the Indian Ocean geoidal low whose effect varies from zero near the 25 • N to −48 mGal at the southern tip of the India (Marsh 1979). Therefore, a part of the predominant negative bias, in the large wavelength Bouguer anomaly over Peninsular India, seems to be related to the density heterogeneities in the upper mantle (Verma and Satyanarayana 1990). To determine the crustal sources of the Bouguer anomaly, the component related to this subcrustal variation, equivalent to first order polynomial approximation, is removed from the observed gravity field.…”

Proterozoic platform sequences of Peninsular India: Implications towards basin evolution and supercontinent assembly

“…The eastern margin of the basin is demarcated by a thrust contact along which the metamorphics of the EGMB are brought over it. The Cuddapah basin has been investigated by various geophysical techniques including deep seismic sounding (DSS) (Kaila et al, 1979(Kaila et al, , 1987, seismic tomography (Gupta et al, 2003), gravity (Verma and Satyanarayana, 1990;Rambabu;Singh and Mishra, 2002), aeromagnetic (Babu , ground-magnetic (Kailasam, 1976) and magnetotelluric (Naganjaneyulu and Harinarayana, 2004) methods. These studies indicate presence of: (a) a 10-11 km thick sedimentary pile over a 40 km thick crust in the eastern part of the basin; (b) step faults in the basement; (c) a mafic-ultramafic lopolith at a shallow depth under the south western part of the basin where mafic sills and volcanics are exposed, and (d) an easterly dipping thrust fault at the eastern margin where high-density lower crust of the EGMB is upthrusted.…”