Geophysical Studies of the Major Sedimentary Basins of the Indian Craton, their Deep Structural Features and Evolution

Chapter 16 Tectonics of the Cuddapah Basin and a model of its evolution: a review

“…A positive gravity anomaly is associated with the outcrop of the thrust (Kaila & Bhatia 1981). The dip of the Velikonda thrust, estimated from the orientation of the mylonitic foliation of the Bairenkonda Quartzite along the eastern boundary of the Nallamalai thrust sheet and from the DSS profile data (Kailasam 1976;Kaila et al 1979;Hari Narain 1987), is about 558 at the level of exposure, although the dip of the fault decreases from north to south along the trend of the thrust. The geometry of the thrust is considered listric in nature, since the footwall is deformed, following the suggestion of Cooper & Trayner (1986).…”

Microearthquake Seismology and Seismotectonics of South Asia

“…Several attempts are made to explain these anomalies. The steep gradient of gravity anomaly along the eastern margin of the basin is attributed to ~12 km thick sediments (Kailasam, 1976), and to an intracrustal discontinuity. (Subrahmanyam and Verma, 1982).…”

“…7.1). Gravity and borehole data suggest that the Vindhyans also underlie the Indo-Gangetic alluvium (Kailasam, 1976). The real northern limits of the Vindhyan basin must possibly be in the now uplifted Lesser Himalayan region in Garhwal and Nepal.…”

“…The gravity gradient is very steep. In a detailed gravity map (Kailasam, 1976), the other major features include a rise in gravity field over Srisailam Plateau in the north and a low over Kurnool. A prominent 30 mGal rise is also mapped at Mehboob Nagar, NW of Cuddapah basin.…”

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.…”