Extension of flood basalt on the northwestern continental margin of India
The Deccan Continental Flood Basalt (DCFB) in central western India is a large igneous province that covers almost one-sixth area of India. It is erupted in less than 1 million years during the magnetic chron 29 r ($$\sim $$∼65.6–64.8 Ma) through the Cretaceous–Tertiary boundary. It is believed that nearly an equivalent area of flood basalt, adjoining the DCFB, is submerged on the northwestern continental margin of India (NWCMI). Onshore information on the DCFB is widely reported in geological and geophysical studies. However, knowledge on the offshore extent of flood basalt is poorly known because of paucity of marine geophysical data and lack of an appropriate approach to determine the flood basalt. To fill this gap in knowledge, P-wave velocity in flood basalt as a proxy, drilled wells results, and published seaward dipping reflectors are used to delineate flood basalt extent on the NWCMI. The results of the study reveal that P-wave velocity in the flood basalt varies from 4.1 to 5.2 km/s. Apart from some isolated basement-high features, it is found that flood basalt lies below sediment and carpets the entire NWCMI extending up to the Laxmi–Laccadive ridges. The depth of occurrence of flood basalt ranges from 800 to 7400 m, with a maximum thickness of $$\sim $$∼3900 m in the eastern part of the Laxmi basin. The article presents preliminary results about the extension of flood basalt on the western continental margin of India which may be useful for researchers and Indian oil industries planning exploration activities in Mesozoic sediment of the margin for hydrocarbon prospects.